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Date:   Sun, 3 May 2020 15:44:13 +0100
From:   Jonathan Cameron <jic23@...nel.org>
To:     William Breathitt Gray <vilhelm.gray@...il.com>
Cc:     kamel.bouhara@...tlin.com, gwendal@...omium.org,
        alexandre.belloni@...tlin.com, david@...hnology.com,
        felipe.balbi@...ux.intel.com, fabien.lahoudere@...labora.com,
        linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-stm32@...md-mailman.stormreply.com,
        linux-arm-kernel@...ts.infradead.org, syednwaris@...il.com,
        patrick.havelange@...ensium.com, fabrice.gasnier@...com,
        mcoquelin.stm32@...il.com, alexandre.torgue@...com
Subject: Re: [PATCH 1/4] counter: Internalize sysfs interface code

On Wed, 29 Apr 2020 14:11:35 -0400
William Breathitt Gray <vilhelm.gray@...il.com> wrote:

> This is a reimplementation of the Generic Counter driver interface.
> There are no modifications to the Counter subsystem userspace interface,
> so existing userspace applications should continue to run seamlessly.
> 
> Overview
> ========
> 
> The purpose of this patch is to internalize the sysfs interface code
> among the various counter drivers into a shared module. Counter drivers
> pass and take data natively (i.e. unsigned long, bool, size_t, etc.) and
> the shared counter module handles the translation between the sysfs
> interface. This gurantees a standard userspace interface for all counter
> drivers, and helps generalize the Generic Counter driver ABI in order to
> support the Generic Counter chardev interface (introduced in a
> subsequent patch) without changes to the existing counter drivers.
> 
> A high-level view of how a count value is passed down from a counter
> driver can be exemplified by the following:
> 
>                  ----------------------
>                 / Counter device       \
>                 +----------------------+
>                 | Count register: 0x28 |
>                 +----------------------+
>                         |
>                  -----------------
>                 / raw count data /
>                 -----------------
>                         |
>                         V
>                 +----------------------------+
>                 | Counter device driver      |----------+
>                 +----------------------------+          |
>                 | Processes data from device |   -------------------
>                 |----------------------------|  / driver callbacks /
>                 | Type: unsigned long        |  -------------------
>                 | Value: 42                  |          |
>                 +----------------------------+          |
>                         |                               |
>                  ----------------                       |
>                 / unsigned long /                       |
>                 ----------------                        |
>                         |                               |
>                         |                               V
>                         |               +----------------------+
>                         |               | Counter core         |
>                         |               +----------------------+
>                         |               | Routes device driver |
>                         |               | callbacks to the     |
>                         |               | userspace interfaces |
>                         |               +----------------------+
>                         |                       |
>                         |                -------------------
>                         |               / driver callbacks /
>                         |               -------------------
>                         |                       |
>                 +-------+                       |
>                 |                               |
>                 |               +---------------+
>                 |               |
>                 V               |
>         +--------------------+  |
>         | Counter sysfs      |<-+
>         +--------------------+
>         | Translates to the  |
>         | standard Counter   |
>         | sysfs output       |
>         |--------------------|
>         | Type: const char * |
>         | Value: "42"        |
>         +--------------------+
>                 |
>          ---------------
>         / const char * /
>         ---------------
>                 |
>                 V
>         +--------------------------------------------------+
>         | `/sys/bus/counter/devices/counterX/countY/count` |
>         +--------------------------------------------------+
>         \ Count: "42"                                      /
>          --------------------------------------------------
> 
> There are three primary components involved:
> 
> 	Counter device driver
> 	---------------------
> 	Communicates with the hardware device to read/write data; e.g.
> 	counter drivers for 104-quad-8, stm32-timer, etc.
> 
> 	Counter core
> 	------------
> 	Registers the counter device driver to the system so that the
> 	respective callbacks are called during userspace interaction
> 
> 	Counter sysfs
> 	-------------
> 	Translates counter data to the standard Counter sysfs interface
> 	format and vice versa
> 
> Driver ABI
> ==========
> 
> This reimplementation entails several changes to the driver ABI. In
> particular, the device driver callbacks are now expected to handle
> standard C datatypes rather than translating the sysfs I/O directly.
> 
> To that end, the struct counter_data structure is introduced to
> establish counter extensions for Signals, Synapses, and Counts:
> 
> struct counter_data {
> 	enum counter_data_type type;
> 	const char *name;
> 	void *read;
Untyped read and write functions seem very likely to be prone to problems.
Perhaps use a union to make sure each of the function patterns is named
and can be explicitly set?

> 	void *write;
> 	void *priv;
> };
> 
> The "type" member specifies the type of data (e.g. unsigned long,
> boolean, etc.) handled by this extension. The "read" and "write" members
> can then be set by the counter device driver with callbacks to handle
> that data.
> 
> Convenience macros such as COUNTER_DATA_UNSIGNED_LONG are provided for
> use by driver authors. In particular, driver authors are expected to use
> the provided macros for standard Counter subsystem attributes in order
> to maintain a consistent interface for userspace. For example, a counter
> device driver may define several standard attributes like so:
> 
> struct counter_data count_ext[] = {
> 	COUNTER_DATA_DIRECTION(count_direction_read),
> 	COUNTER_DATA_ENABLE(count_enable_read, count_enable_write),
> 	COUNTER_DATA_CEILING(count_ceiling_read, count_ceiling_write),
> };
> 
> This makes it intuitive to see, add, and modify the attributes that are
> supported by this driver ("direction", "enable", and "ceiling") and to
> maintain this code without getting lost in a web of struct braces.
> 
> Callbacks must match the function type expected for the respective
> component or extension. These types are defined in the
> drivers/counter/counter-function-types.h file.
> 
> The corresponding prototypes for the callbacks would be:
> 
> int count_direction_read(struct counter_device *counter,
> 			 struct counter_count *count,
> 			 enum counter_count_direction *direction);
> int count_enable_read(struct counter_device *counter,
> 		      struct counter_count *count, bool *enable);
> int count_enable_write(struct counter_device *counter,
> 		       struct counter_count *count, bool enable);
> int count_ceiling_read(struct counter_device *counter,
> 		       struct counter_count *count,
> 		       unsigned long *ceiling);
> int count_ceiling_write(struct counter_device *counter,
> 			struct counter_count *count,
> 			unsigned long ceiling);

Perhaps used explicit sizes rather than long which can vary
across different platforms.  Starting out with 64 bits
seems like a good idea for counters.


> 
> In this way, driver authors no longer need to mess with sysfs strings
> and are instead able to focus on what they actually care about doing --
> getting data to/from the devices -- while the Generic Counter interface
> handles the translation of that data for them between the various
> userspace interfaces (e.g. sysfs and chardev).
> 
> Architecture
> ============
> 
> Counter device registration is the same as before: drivers populate a
> struct counter_device with components and callbacks, then pass the
> structure to the devm_counter_register function. However, what's
> different now is how the Counter subsystem code handles this
> registration internally.
> 
> Whereas before callbacks would interact directly with sysfs data, this
> interaction is now abstracted and instead callbacks interact with native
> C data types. The counter_data structure forms the basis for Counter
> extentions.
> 
> The counter-sysfs.c file contains the code to parse through the
> counter_device structure and register the requested components and
> extensions. Attributes are created and populated based on type, with
> respective translation functions to handle the mapping between sysfs and
> the counter driver callbacks.
> 
> The counter-sysfs-callbacks.c file contains the code to map between the
> abstract read and write callbacks of the counter driver and the more
> specific show and store callbacks expected for sysfs. This mapping is
> represented by the counter_data_sysfs_show and counter_data_sysfs_store
> arrays, which point to the show and store translation functions for each
> attribute.
> 
> The translation performed for each attribute is straightforward: the
> attribute type and data is parsed from the counter_attribute structure,
> the respective counter driver read/write callback is cast, and sysfs
> I/O is handled before or after the driver read/write function is called.
> 
> The counter-function-types.h file contains the typedefs to simplify this
> casting code. The counter-strings.h file contains the standard Counter
> sysfs I/O string constants to maintain a consistent interface for
> userspace.
> 
> Cc: Syed Nayyar Waris <syednwaris@...il.com>
> Cc: Patrick Havelange <patrick.havelange@...ensium.com>
> Cc: Fabrice Gasnier <fabrice.gasnier@...com>
> Cc: Maxime Coquelin <mcoquelin.stm32@...il.com>
> Cc: Alexandre Torgue <alexandre.torgue@...com>
> Cc: David Lechner <david@...hnology.com>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@...il.com>

Various specific comments inline.

In general, moving to a non string based interface seems to eventually happen
to all subsystems ;)  Strings just don't lend themselves to flexible interfaces.

Basic approach looks reasonable to me.

Jonathan


> ---
>  MAINTAINERS                               |    2 +-
>  drivers/counter/104-quad-8.c              |  437 +++---
>  drivers/counter/Makefile                  |    1 +
>  drivers/counter/counter-core.c            |  190 +++
>  drivers/counter/counter-function-types.h  |   81 ++
>  drivers/counter/counter-strings.h         |   46 +
>  drivers/counter/counter-sysfs-callbacks.c |  566 ++++++++
>  drivers/counter/counter-sysfs-callbacks.h |   28 +
>  drivers/counter/counter-sysfs.c           |  524 ++++++++
>  drivers/counter/counter-sysfs.h           |   14 +
>  drivers/counter/counter.c                 | 1496 ---------------------
>  drivers/counter/ftm-quaddec.c             |   46 +-
>  drivers/counter/stm32-lptimer-cnt.c       |  159 +--
>  drivers/counter/stm32-timer-cnt.c         |  132 +-
>  drivers/counter/ti-eqep.c                 |  170 +--
>  include/linux/counter.h                   |  545 +++-----
>  include/linux/counter_enum.h              |   45 -
>  include/uapi/linux/counter-types.h        |   67 +
>  18 files changed, 2130 insertions(+), 2419 deletions(-)
>  create mode 100644 drivers/counter/counter-core.c
>  create mode 100644 drivers/counter/counter-function-types.h
>  create mode 100644 drivers/counter/counter-strings.h
>  create mode 100644 drivers/counter/counter-sysfs-callbacks.c
>  create mode 100644 drivers/counter/counter-sysfs-callbacks.h
>  create mode 100644 drivers/counter/counter-sysfs.c
>  create mode 100644 drivers/counter/counter-sysfs.h
>  delete mode 100644 drivers/counter/counter.c
>  delete mode 100644 include/linux/counter_enum.h
>  create mode 100644 include/uapi/linux/counter-types.h
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 10eb348c801c..89def3fe1c76 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -4367,7 +4367,7 @@ F:	Documentation/ABI/testing/sysfs-bus-counter*
>  F:	Documentation/driver-api/generic-counter.rst
>  F:	drivers/counter/
>  F:	include/linux/counter.h
> -F:	include/linux/counter_enum.h
> +F:	include/uapi/linux/counter-types.h
>  
>  CPMAC ETHERNET DRIVER
>  M:	Florian Fainelli <f.fainelli@...il.com>
> diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
> index 9dab190c49b0..bc1801e1bce9 100644
> --- a/drivers/counter/104-quad-8.c
> +++ b/drivers/counter/104-quad-8.c
> @@ -651,21 +651,22 @@ static int quad8_count_write(struct counter_device *counter,
>  }
>  
>  enum quad8_count_function {
> -	QUAD8_COUNT_FUNCTION_PULSE_DIRECTION = 0,
> -	QUAD8_COUNT_FUNCTION_QUADRATURE_X1,
> -	QUAD8_COUNT_FUNCTION_QUADRATURE_X2,
> -	QUAD8_COUNT_FUNCTION_QUADRATURE_X4
> +	QUAD8_COUNT_FUNCTION_PULSE_DIRECTION = COUNTER_COUNT_FUNCTION_PULSE_DIRECTION,
> +	QUAD8_COUNT_FUNCTION_QUADRATURE_X1 = COUNTER_COUNT_FUNCTION_QUADRATURE_X1_A,
> +	QUAD8_COUNT_FUNCTION_QUADRATURE_X2 = COUNTER_COUNT_FUNCTION_QUADRATURE_X2_A,
> +	QUAD8_COUNT_FUNCTION_QUADRATURE_X4 = COUNTER_COUNT_FUNCTION_QUADRATURE_X4,

Feels like you'd be better off just dropping the local enum entirely.
I guess it gives you a small amount of protection against undefined values,
but at cost of some otherwise pointless indirection.

>  };
>  
> -static enum counter_count_function quad8_count_functions_list[] = {
> -	[QUAD8_COUNT_FUNCTION_PULSE_DIRECTION] = COUNTER_COUNT_FUNCTION_PULSE_DIRECTION,
> -	[QUAD8_COUNT_FUNCTION_QUADRATURE_X1] = COUNTER_COUNT_FUNCTION_QUADRATURE_X1_A,
> -	[QUAD8_COUNT_FUNCTION_QUADRATURE_X2] = COUNTER_COUNT_FUNCTION_QUADRATURE_X2_A,
> -	[QUAD8_COUNT_FUNCTION_QUADRATURE_X4] = COUNTER_COUNT_FUNCTION_QUADRATURE_X4
> +static const enum counter_count_function quad8_count_functions_list[] = {
> +	QUAD8_COUNT_FUNCTION_PULSE_DIRECTION,
> +	QUAD8_COUNT_FUNCTION_QUADRATURE_X1,
> +	QUAD8_COUNT_FUNCTION_QUADRATURE_X2,
> +	QUAD8_COUNT_FUNCTION_QUADRATURE_X4,
>  };
>  
> -static int quad8_function_get(struct counter_device *counter,
> -	struct counter_count *count, size_t *function)
> +static int quad8_function_read(struct counter_device *counter,
> +			       struct counter_count *count,
> +			       enum counter_count_function *function)
>  {
>  	const struct quad8_iio *const priv = counter->priv;
>  	const int id = count->id;
> @@ -690,11 +691,13 @@ static int quad8_function_get(struct counter_device *counter,
>  	return 0;
>  }
>  
> -static int quad8_function_set(struct counter_device *counter,
> -	struct counter_count *count, size_t function)
> +static int quad8_function_write(struct counter_device *counter,
> +				struct counter_count *count,
> +				enum counter_count_function function)
>  {
>  	struct quad8_iio *const priv = counter->priv;
>  	const int id = count->id;
> +	const enum quad8_count_function cnt_function = function;
>  	unsigned int *const quadrature_mode = priv->quadrature_mode + id;
>  	unsigned int *const scale = priv->quadrature_scale + id;
>  	unsigned int mode_cfg = priv->count_mode[id] << 1;
> @@ -702,7 +705,7 @@ static int quad8_function_set(struct counter_device *counter,
>  	const unsigned int idr_cfg = priv->index_polarity[id] << 1;
>  	const int base_offset = priv->base + 2 * id + 1;
>  
> -	if (function == QUAD8_COUNT_FUNCTION_PULSE_DIRECTION) {
> +	if (cnt_function == QUAD8_COUNT_FUNCTION_PULSE_DIRECTION) {
>  		*quadrature_mode = 0;
>  
>  		/* Quadrature scaling only available in quadrature mode */
> @@ -717,7 +720,7 @@ static int quad8_function_set(struct counter_device *counter,
>  	} else {
>  		*quadrature_mode = 1;
>  
> -		switch (function) {
> +		switch (cnt_function) {
>  		case QUAD8_COUNT_FUNCTION_QUADRATURE_X1:
>  			*scale = 0;
>  			mode_cfg |= QUAD8_CMR_QUADRATURE_X1;
> @@ -730,6 +733,7 @@ static int quad8_function_set(struct counter_device *counter,
>  			*scale = 2;
>  			mode_cfg |= QUAD8_CMR_QUADRATURE_X4;
>  			break;
> +		default: return -EINVAL;
>  		}
>  	}
>  
> @@ -739,8 +743,9 @@ static int quad8_function_set(struct counter_device *counter,
>  	return 0;
>  }
>  
> -static void quad8_direction_get(struct counter_device *counter,
> -	struct counter_count *count, enum counter_count_direction *direction)
> +static int quad8_direction_read(struct counter_device *counter,
> +				struct counter_count *count,
> +				enum counter_count_direction *direction)
>  {
>  	const struct quad8_iio *const priv = counter->priv;
>  	unsigned int ud_flag;
> @@ -751,91 +756,81 @@ static void quad8_direction_get(struct counter_device *counter,
>  
>  	*direction = (ud_flag) ? COUNTER_COUNT_DIRECTION_FORWARD :
>  		COUNTER_COUNT_DIRECTION_BACKWARD;
> -}
>  
> -enum quad8_synapse_action {
> -	QUAD8_SYNAPSE_ACTION_NONE = 0,
> -	QUAD8_SYNAPSE_ACTION_RISING_EDGE,
> -	QUAD8_SYNAPSE_ACTION_FALLING_EDGE,
> -	QUAD8_SYNAPSE_ACTION_BOTH_EDGES
> -};
> +	return 0;
> +}
>  
> -static enum counter_synapse_action quad8_index_actions_list[] = {
> -	[QUAD8_SYNAPSE_ACTION_NONE] = COUNTER_SYNAPSE_ACTION_NONE,
> -	[QUAD8_SYNAPSE_ACTION_RISING_EDGE] = COUNTER_SYNAPSE_ACTION_RISING_EDGE
> +static const enum counter_synapse_action quad8_index_actions_list[] = {
> +	COUNTER_SYNAPSE_ACTION_NONE,
> +	COUNTER_SYNAPSE_ACTION_RISING_EDGE,
>  };
>  
> -static enum counter_synapse_action quad8_synapse_actions_list[] = {
> -	[QUAD8_SYNAPSE_ACTION_NONE] = COUNTER_SYNAPSE_ACTION_NONE,
> -	[QUAD8_SYNAPSE_ACTION_RISING_EDGE] = COUNTER_SYNAPSE_ACTION_RISING_EDGE,
> -	[QUAD8_SYNAPSE_ACTION_FALLING_EDGE] = COUNTER_SYNAPSE_ACTION_FALLING_EDGE,
> -	[QUAD8_SYNAPSE_ACTION_BOTH_EDGES] = COUNTER_SYNAPSE_ACTION_BOTH_EDGES
> +static const enum counter_synapse_action quad8_synapse_actions_list[] = {
> +	COUNTER_SYNAPSE_ACTION_NONE,
> +	COUNTER_SYNAPSE_ACTION_RISING_EDGE,
> +	COUNTER_SYNAPSE_ACTION_FALLING_EDGE,
> +	COUNTER_SYNAPSE_ACTION_BOTH_EDGES,
>  };
>  
> -static int quad8_action_get(struct counter_device *counter,
> -	struct counter_count *count, struct counter_synapse *synapse,
> -	size_t *action)
> +static int quad8_action_read(struct counter_device *counter,
> +			     struct counter_count *count,
> +			     struct counter_synapse *synapse,
> +			     enum counter_synapse_action *action)
>  {
>  	struct quad8_iio *const priv = counter->priv;
>  	int err;
> -	size_t function = 0;
> +	enum counter_count_function function = 0;
>  	const size_t signal_a_id = count->synapses[0].signal->id;
>  	enum counter_count_direction direction;
>  
>  	/* Handle Index signals */
>  	if (synapse->signal->id >= 16) {
>  		if (priv->preset_enable[count->id])
> -			*action = QUAD8_SYNAPSE_ACTION_RISING_EDGE;
> +			*action = COUNTER_SYNAPSE_ACTION_RISING_EDGE;
>  		else
> -			*action = QUAD8_SYNAPSE_ACTION_NONE;
> +			*action = COUNTER_SYNAPSE_ACTION_NONE;
>  
>  		return 0;
>  	}
>  
> -	err = quad8_function_get(counter, count, &function);
> +	err = quad8_function_read(counter, count, &function);
>  	if (err)
>  		return err;
>  
>  	/* Default action mode */
> -	*action = QUAD8_SYNAPSE_ACTION_NONE;
> +	*action = COUNTER_SYNAPSE_ACTION_NONE;
>  
>  	/* Determine action mode based on current count function mode */
>  	switch (function) {
>  	case QUAD8_COUNT_FUNCTION_PULSE_DIRECTION:
>  		if (synapse->signal->id == signal_a_id)
> -			*action = QUAD8_SYNAPSE_ACTION_RISING_EDGE;
> +			*action = COUNTER_SYNAPSE_ACTION_RISING_EDGE;
>  		break;
>  	case QUAD8_COUNT_FUNCTION_QUADRATURE_X1:
>  		if (synapse->signal->id == signal_a_id) {
> -			quad8_direction_get(counter, count, &direction);
> +			err = quad8_direction_read(counter, count, &direction);
> +			if (err)
> +				return err;
>  
>  			if (direction == COUNTER_COUNT_DIRECTION_FORWARD)
> -				*action = QUAD8_SYNAPSE_ACTION_RISING_EDGE;
> +				*action = COUNTER_SYNAPSE_ACTION_RISING_EDGE;
>  			else
> -				*action = QUAD8_SYNAPSE_ACTION_FALLING_EDGE;
> +				*action = COUNTER_SYNAPSE_ACTION_FALLING_EDGE;
>  		}
>  		break;
>  	case QUAD8_COUNT_FUNCTION_QUADRATURE_X2:
>  		if (synapse->signal->id == signal_a_id)
> -			*action = QUAD8_SYNAPSE_ACTION_BOTH_EDGES;
> +			*action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES;
>  		break;
>  	case QUAD8_COUNT_FUNCTION_QUADRATURE_X4:
> -		*action = QUAD8_SYNAPSE_ACTION_BOTH_EDGES;
> +		*action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES;
>  		break;
> +	default: return -EINVAL;
>  	}
>  
>  	return 0;
>  }
>  
> -static const struct counter_ops quad8_ops = {
> -	.signal_read = quad8_signal_read,
> -	.count_read = quad8_count_read,
> -	.count_write = quad8_count_write,
> -	.function_get = quad8_function_get,
> -	.function_set = quad8_function_set,
> -	.action_get = quad8_action_get
> -};
> -
>  static int quad8_index_polarity_get(struct counter_device *counter,
>  	struct counter_signal *signal, size_t *index_polarity)
>  {
> @@ -864,12 +859,7 @@ static int quad8_index_polarity_set(struct counter_device *counter,
>  	return 0;
>  }
>  
> -static struct counter_signal_enum_ext quad8_index_pol_enum = {
> -	.items = quad8_index_polarity_modes,
> -	.num_items = ARRAY_SIZE(quad8_index_polarity_modes),
> -	.get = quad8_index_polarity_get,
> -	.set = quad8_index_polarity_set
> -};
> +static DEFINE_COUNTER_ENUM(quad8_index_pol_enum, quad8_index_polarity_modes);
>  
>  static int quad8_synchronous_mode_get(struct counter_device *counter,
>  	struct counter_signal *signal, size_t *synchronous_mode)
> @@ -903,22 +893,21 @@ static int quad8_synchronous_mode_set(struct counter_device *counter,
>  	return 0;
>  }
>  
> -static struct counter_signal_enum_ext quad8_syn_mode_enum = {
> -	.items = quad8_synchronous_modes,
> -	.num_items = ARRAY_SIZE(quad8_synchronous_modes),
> -	.get = quad8_synchronous_mode_get,
> -	.set = quad8_synchronous_mode_set
> -};
> +static DEFINE_COUNTER_ENUM(quad8_syn_mode_enum, quad8_synchronous_modes);
>  
> -static ssize_t quad8_count_floor_read(struct counter_device *counter,
> -	struct counter_count *count, void *private, char *buf)
> +static int quad8_count_floor_read(struct counter_device *counter,
> +				  struct counter_count *count,
> +				  unsigned long *floor)
>  {
>  	/* Only a floor of 0 is supported */
> -	return sprintf(buf, "0\n");
> +	*floor = 0;
> +
> +	return 0;
>  }
>  
> -static int quad8_count_mode_get(struct counter_device *counter,
> -	struct counter_count *count, size_t *cnt_mode)
> +static int quad8_count_mode_read(struct counter_device *counter,
> +				 struct counter_count *count,
> +				 enum counter_count_mode *cnt_mode)
>  {
>  	const struct quad8_iio *const priv = counter->priv;
>  
> @@ -941,33 +930,35 @@ static int quad8_count_mode_get(struct counter_device *counter,
>  	return 0;
>  }
>  
> -static int quad8_count_mode_set(struct counter_device *counter,
> -	struct counter_count *count, size_t cnt_mode)
> +static int quad8_count_mode_write(struct counter_device *counter,
> +				  struct counter_count *count,
> +				  enum counter_count_mode cnt_mode)
>  {
>  	struct quad8_iio *const priv = counter->priv;
> +	unsigned int count_mode = 0;
>  	unsigned int mode_cfg;
>  	const int base_offset = priv->base + 2 * count->id + 1;
>  
>  	/* Map Generic Counter count mode to 104-QUAD-8 count mode */
>  	switch (cnt_mode) {
>  	case COUNTER_COUNT_MODE_NORMAL:
> -		cnt_mode = 0;
> +		count_mode = 0;
>  		break;
>  	case COUNTER_COUNT_MODE_RANGE_LIMIT:
> -		cnt_mode = 1;
> +		count_mode = 1;
>  		break;
>  	case COUNTER_COUNT_MODE_NON_RECYCLE:
> -		cnt_mode = 2;
> +		count_mode = 2;
>  		break;
>  	case COUNTER_COUNT_MODE_MODULO_N:
> -		cnt_mode = 3;
> +		count_mode = 3;
>  		break;
>  	}
>  
> -	priv->count_mode[count->id] = cnt_mode;
> +	priv->count_mode[count->id] = count_mode;
>  
>  	/* Set count mode configuration value */
> -	mode_cfg = cnt_mode << 1;
> +	mode_cfg = count_mode << 1;
>  
>  	/* Add quadrature mode configuration */
>  	if (priv->quadrature_mode[count->id])
> @@ -979,92 +970,89 @@ static int quad8_count_mode_set(struct counter_device *counter,
>  	return 0;
>  }
>  
> -static struct counter_count_enum_ext quad8_cnt_mode_enum = {
> -	.items = counter_count_mode_str,
> -	.num_items = ARRAY_SIZE(counter_count_mode_str),
> -	.get = quad8_count_mode_get,
> -	.set = quad8_count_mode_set
> +static enum counter_count_mode quad8_cnt_modes[] = {
> +	COUNTER_COUNT_MODE_NORMAL,
> +	COUNTER_COUNT_MODE_RANGE_LIMIT,
> +	COUNTER_COUNT_MODE_NON_RECYCLE,
> +	COUNTER_COUNT_MODE_MODULO_N,
>  };
>  
> -static ssize_t quad8_count_direction_read(struct counter_device *counter,
> -	struct counter_count *count, void *priv, char *buf)
> -{
> -	enum counter_count_direction dir;
> -
> -	quad8_direction_get(counter, count, &dir);
> -
> -	return sprintf(buf, "%s\n", counter_count_direction_str[dir]);
> -}
> +static DEFINE_COUNTER_AVAILABLE(quad8_count_mode_available, quad8_cnt_modes);
>  
> -static ssize_t quad8_count_enable_read(struct counter_device *counter,
> -	struct counter_count *count, void *private, char *buf)
> +static int quad8_count_enable_read(struct counter_device *counter,
> +				   struct counter_count *count, bool *enable)
>  {
>  	const struct quad8_iio *const priv = counter->priv;
>  
> -	return sprintf(buf, "%u\n", priv->ab_enable[count->id]);
> +	*enable = priv->ab_enable[count->id];
> +
> +	return 0;
>  }
>  
> -static ssize_t quad8_count_enable_write(struct counter_device *counter,
> -	struct counter_count *count, void *private, const char *buf, size_t len)
> +static int quad8_count_enable_write(struct counter_device *counter,
> +				    struct counter_count *count, bool enable)
>  {
>  	struct quad8_iio *const priv = counter->priv;
>  	const int base_offset = priv->base + 2 * count->id;
> -	int err;
> -	bool ab_enable;
>  	unsigned int ior_cfg;
>  
> -	err = kstrtobool(buf, &ab_enable);
> -	if (err)
> -		return err;
> +	priv->ab_enable[count->id] = enable;
>  
> -	priv->ab_enable[count->id] = ab_enable;
> -
> -	ior_cfg = ab_enable | priv->preset_enable[count->id] << 1;
> +	ior_cfg = enable | priv->preset_enable[count->id] << 1;
>  
>  	/* Load I/O control configuration */
>  	outb(QUAD8_CTR_IOR | ior_cfg, base_offset + 1);
>  
> -	return len;
> +	return 0;
>  }
>  
> -static int quad8_error_noise_get(struct counter_device *counter,
> -	struct counter_count *count, size_t *noise_error)
> +static ssize_t quad8_error_noise_read(struct counter_device *counter,
> +				      struct counter_count *count, char *buf,
> +				      size_t size)
>  {
>  	const struct quad8_iio *const priv = counter->priv;
>  	const int base_offset = priv->base + 2 * count->id + 1;
> +	size_t noise_error;
>  
> -	*noise_error = !!(inb(base_offset) & QUAD8_FLAG_E);
> +	noise_error = !!(inb(base_offset) & QUAD8_FLAG_E);
>  
> -	return 0;
> +	return snprintf(buf, size, "%s\n",
> +			quad8_noise_error_states[noise_error]);
>  }
>  
> -static struct counter_count_enum_ext quad8_error_noise_enum = {
> -	.items = quad8_noise_error_states,
> -	.num_items = ARRAY_SIZE(quad8_noise_error_states),
> -	.get = quad8_error_noise_get
> -};
> +static ssize_t quad8_error_noise_available_read(struct counter_device *counter,
> +						struct counter_count *count,
> +						char *buf, size_t size)
> +{
> +	size_t i;
> +	size_t len = 0;
>  
> -static ssize_t quad8_count_preset_read(struct counter_device *counter,
> -	struct counter_count *count, void *private, char *buf)
> +	for (i = 0; i < ARRAY_SIZE(quad8_noise_error_states) && size > 1; i++)
> +		len += scnprintf(buf + len, size - len, "%s\n",
> +				 quad8_noise_error_states[i]);
> +
> +	return len;
> +}
> +
> +static int quad8_count_preset_read(struct counter_device *counter,
> +				   struct counter_count *count,
> +				   unsigned long *preset)
>  {
>  	const struct quad8_iio *const priv = counter->priv;
>  
> -	return sprintf(buf, "%u\n", priv->preset[count->id]);
> +	*preset = priv->preset[count->id];
> +
> +	return 0;
>  }
>  
> -static ssize_t quad8_count_preset_write(struct counter_device *counter,
> -	struct counter_count *count, void *private, const char *buf, size_t len)
> +static int quad8_count_preset_write(struct counter_device *counter,
> +				    struct counter_count *count,
> +				    unsigned long preset)
>  {
>  	struct quad8_iio *const priv = counter->priv;
>  	const int base_offset = priv->base + 2 * count->id;
> -	unsigned int preset;
> -	int ret;
>  	int i;
>  
> -	ret = kstrtouint(buf, 0, &preset);
> -	if (ret)
> -		return ret;
> -
>  	/* Only 24-bit values are supported */
>  	if (preset > 0xFFFFFF)
>  		return -EINVAL;
> @@ -1078,11 +1066,12 @@ static ssize_t quad8_count_preset_write(struct counter_device *counter,
>  	for (i = 0; i < 3; i++)
>  		outb(preset >> (8 * i), base_offset);
>  
> -	return len;
> +	return 0;
>  }
>  
> -static ssize_t quad8_count_ceiling_read(struct counter_device *counter,
> -	struct counter_count *count, void *private, char *buf)
> +static int quad8_count_ceiling_read(struct counter_device *counter,
> +				    struct counter_count *count,
> +				    unsigned long *ceiling)
>  {
>  	const struct quad8_iio *const priv = counter->priv;
>  
> @@ -1090,15 +1079,18 @@ static ssize_t quad8_count_ceiling_read(struct counter_device *counter,
>  	switch (priv->count_mode[count->id]) {
>  	case 1:
>  	case 3:
> -		return quad8_count_preset_read(counter, count, private, buf);
> +		return quad8_count_preset_read(counter, count, ceiling);
>  	}
>  
>  	/* By default 0x1FFFFFF (25 bits unsigned) is maximum count */
> -	return sprintf(buf, "33554431\n");
> +	*ceiling = 0x1FFFFFF;
> +
> +	return 0;
>  }
>  
> -static ssize_t quad8_count_ceiling_write(struct counter_device *counter,
> -	struct counter_count *count, void *private, const char *buf, size_t len)
> +static int quad8_count_ceiling_write(struct counter_device *counter,
> +				     struct counter_count *count,
> +				     unsigned long ceiling)
>  {
>  	struct quad8_iio *const priv = counter->priv;
>  
> @@ -1106,34 +1098,31 @@ static ssize_t quad8_count_ceiling_write(struct counter_device *counter,
>  	switch (priv->count_mode[count->id]) {
>  	case 1:
>  	case 3:
> -		return quad8_count_preset_write(counter, count, private, buf,
> -						len);
> +		return quad8_count_preset_write(counter, count, ceiling);
>  	}
>  
> -	return len;
> +	return -EINVAL;
>  }
>  
> -static ssize_t quad8_count_preset_enable_read(struct counter_device *counter,
> -	struct counter_count *count, void *private, char *buf)
> +static int quad8_count_preset_enable_read(struct counter_device *counter,
> +					  struct counter_count *count,
> +					  bool *preset_enable)
>  {
>  	const struct quad8_iio *const priv = counter->priv;
>  
> -	return sprintf(buf, "%u\n", !priv->preset_enable[count->id]);
> +	*preset_enable = !priv->preset_enable[count->id];
> +
> +	return 0;
>  }
>  
> -static ssize_t quad8_count_preset_enable_write(struct counter_device *counter,
> -	struct counter_count *count, void *private, const char *buf, size_t len)
> +static int quad8_count_preset_enable_write(struct counter_device *counter,
> +					   struct counter_count *count,
> +					   bool preset_enable)
>  {
>  	struct quad8_iio *const priv = counter->priv;
>  	const int base_offset = priv->base + 2 * count->id + 1;
> -	bool preset_enable;
> -	int ret;
>  	unsigned int ior_cfg;
>  
> -	ret = kstrtobool(buf, &preset_enable);
> -	if (ret)
> -		return ret;
> -
>  	/* Preset enable is active low in Input/Output Control register */
>  	preset_enable = !preset_enable;
>  
> @@ -1144,18 +1133,16 @@ static ssize_t quad8_count_preset_enable_write(struct counter_device *counter,
>  	/* Load I/O control configuration to Input / Output Control Register */
>  	outb(QUAD8_CTR_IOR | ior_cfg, base_offset);
>  
> -	return len;
> +	return 0;
>  }
>  
> -static ssize_t quad8_signal_cable_fault_read(struct counter_device *counter,
> -					     struct counter_signal *signal,
> -					     void *private, char *buf)
> +static int quad8_signal_cable_fault_read(struct counter_device *counter,
> +	struct counter_signal *signal, bool *cable_fault)
>  {
>  	const struct quad8_iio *const priv = counter->priv;
>  	const size_t channel_id = signal->id / 2;
>  	const bool disabled = !(priv->cable_fault_enable & BIT(channel_id));
>  	unsigned int status;
> -	unsigned int fault;
>  
>  	if (disabled)
>  		return -EINVAL;
> @@ -1164,36 +1151,29 @@ static ssize_t quad8_signal_cable_fault_read(struct counter_device *counter,
>  	status = inb(priv->base + QUAD8_DIFF_ENCODER_CABLE_STATUS);
>  
>  	/* Mask respective channel and invert logic */
> -	fault = !(status & BIT(channel_id));
> +	*cable_fault = !(status & BIT(channel_id));
>  
> -	return sprintf(buf, "%u\n", fault);
> +	return 0;
>  }
>  
> -static ssize_t quad8_signal_cable_fault_enable_read(
> -	struct counter_device *counter, struct counter_signal *signal,
> -	void *private, char *buf)
> +static int quad8_signal_cable_fault_enable_read(struct counter_device *counter,
> +	struct counter_signal *signal, bool *enable)
>  {
>  	const struct quad8_iio *const priv = counter->priv;
>  	const size_t channel_id = signal->id / 2;
> -	const unsigned int enb = !!(priv->cable_fault_enable & BIT(channel_id));
>  
> -	return sprintf(buf, "%u\n", enb);
> +	*enable = !!(priv->cable_fault_enable & BIT(channel_id));
> +
> +	return 0;
>  }
>  
> -static ssize_t quad8_signal_cable_fault_enable_write(
> -	struct counter_device *counter, struct counter_signal *signal,
> -	void *private, const char *buf, size_t len)
> +static int quad8_signal_cable_fault_enable_write(struct counter_device *counter,
> +	struct counter_signal *signal, bool enable)
>  {
>  	struct quad8_iio *const priv = counter->priv;
>  	const size_t channel_id = signal->id / 2;
> -	bool enable;
> -	int ret;
>  	unsigned int cable_fault_enable;
>  
> -	ret = kstrtobool(buf, &enable);
> -	if (ret)
> -		return ret;
> -
>  	if (enable)
>  		priv->cable_fault_enable |= BIT(channel_id);
>  	else
> @@ -1204,31 +1184,29 @@ static ssize_t quad8_signal_cable_fault_enable_write(
>  
>  	outb(cable_fault_enable, priv->base + QUAD8_DIFF_ENCODER_CABLE_STATUS);
>  
> -	return len;
> +	return 0;
>  }
>  
> -static ssize_t quad8_signal_fck_prescaler_read(struct counter_device *counter,
> -	struct counter_signal *signal, void *private, char *buf)
> +static int quad8_signal_fck_prescaler_read(struct counter_device *counter,
> +	struct counter_signal *signal, unsigned long *prescaler)
>  {
>  	const struct quad8_iio *const priv = counter->priv;
> -	const size_t channel_id = signal->id / 2;
>  
> -	return sprintf(buf, "%u\n", priv->fck_prescaler[channel_id]);
> +	*prescaler = priv->fck_prescaler[signal->id / 2];
> +
> +	return 0;
>  }
>  
> -static ssize_t quad8_signal_fck_prescaler_write(struct counter_device *counter,
> -	struct counter_signal *signal, void *private, const char *buf,
> -	size_t len)
> +static int quad8_signal_fck_prescaler_write(struct counter_device *counter,
> +	struct counter_signal *signal, unsigned long prescaler)
>  {
>  	struct quad8_iio *const priv = counter->priv;
>  	const size_t channel_id = signal->id / 2;
>  	const int base_offset = priv->base + 2 * channel_id;
> -	u8 prescaler;
> -	int ret;
>  
> -	ret = kstrtou8(buf, 0, &prescaler);
> -	if (ret)
> -		return ret;
> +	/* prescaler is an 8-bit value */
> +	if (prescaler > 255)
> +		return -ERANGE;
>  
>  	priv->fck_prescaler[channel_id] = prescaler;
>  
> @@ -1240,31 +1218,28 @@ static ssize_t quad8_signal_fck_prescaler_write(struct counter_device *counter,
>  	outb(QUAD8_CTR_RLD | QUAD8_RLD_RESET_BP | QUAD8_RLD_PRESET_PSC,
>  	     base_offset + 1);
>  
> -	return len;
> +	return 0;
>  }
>  
> -static const struct counter_signal_ext quad8_signal_ext[] = {
> -	{
> -		.name = "cable_fault",
> -		.read = quad8_signal_cable_fault_read
> -	},
> -	{
> -		.name = "cable_fault_enable",
> -		.read = quad8_signal_cable_fault_enable_read,
> -		.write = quad8_signal_cable_fault_enable_write
> -	},
> -	{
> -		.name = "filter_clock_prescaler",
> -		.read = quad8_signal_fck_prescaler_read,
> -		.write = quad8_signal_fck_prescaler_write
> -	}
> +static struct counter_data quad8_signal_ext[] = {
> +	COUNTER_DATA_BOOL("cable_fault", quad8_signal_cable_fault_read, NULL),
> +	COUNTER_DATA_BOOL("cable_fault_enable",
> +			  quad8_signal_cable_fault_enable_read,
> +			  quad8_signal_cable_fault_enable_write),
> +	COUNTER_DATA_UNSIGNED_LONG("filter_clock_prescaler",
> +				   quad8_signal_fck_prescaler_read,
> +				   quad8_signal_fck_prescaler_write)
>  };
>  
> -static const struct counter_signal_ext quad8_index_ext[] = {
> -	COUNTER_SIGNAL_ENUM("index_polarity", &quad8_index_pol_enum),
> -	COUNTER_SIGNAL_ENUM_AVAILABLE("index_polarity",	&quad8_index_pol_enum),
> -	COUNTER_SIGNAL_ENUM("synchronous_mode", &quad8_syn_mode_enum),
> -	COUNTER_SIGNAL_ENUM_AVAILABLE("synchronous_mode", &quad8_syn_mode_enum)
> +static struct counter_data quad8_index_ext[] = {
> +	COUNTER_DATA_ENUM_AND_AVAILABLE("index_polarity",
> +					quad8_index_polarity_get,
> +					quad8_index_polarity_set,
> +					quad8_index_pol_enum),
> +	COUNTER_DATA_ENUM_AND_AVAILABLE("synchronous_mode",
> +					quad8_synchronous_mode_get,
> +					quad8_synchronous_mode_set,
> +					quad8_syn_mode_enum),
>  };
>  
>  #define QUAD8_QUAD_SIGNAL(_id, _name) {		\
> @@ -1333,39 +1308,20 @@ static struct counter_synapse quad8_count_synapses[][3] = {
>  	QUAD8_COUNT_SYNAPSES(6), QUAD8_COUNT_SYNAPSES(7)
>  };
>  
> -static const struct counter_count_ext quad8_count_ext[] = {
> -	{
> -		.name = "ceiling",
> -		.read = quad8_count_ceiling_read,
> -		.write = quad8_count_ceiling_write
> -	},
> -	{
> -		.name = "floor",
> -		.read = quad8_count_floor_read
> -	},
> -	COUNTER_COUNT_ENUM("count_mode", &quad8_cnt_mode_enum),
> -	COUNTER_COUNT_ENUM_AVAILABLE("count_mode", &quad8_cnt_mode_enum),
> -	{
> -		.name = "direction",
> -		.read = quad8_count_direction_read
> -	},
> -	{
> -		.name = "enable",
> -		.read = quad8_count_enable_read,
> -		.write = quad8_count_enable_write
> -	},
> -	COUNTER_COUNT_ENUM("error_noise", &quad8_error_noise_enum),
> -	COUNTER_COUNT_ENUM_AVAILABLE("error_noise", &quad8_error_noise_enum),
> -	{
> -		.name = "preset",
> -		.read = quad8_count_preset_read,
> -		.write = quad8_count_preset_write
> -	},
> -	{
> -		.name = "preset_enable",
> -		.read = quad8_count_preset_enable_read,
> -		.write = quad8_count_preset_enable_write
> -	}
> +static struct counter_data quad8_count_ext[] = {
> +	COUNTER_DATA_CEILING(quad8_count_ceiling_read,
> +			     quad8_count_ceiling_write),
> +	COUNTER_DATA_FLOOR(quad8_count_floor_read, NULL),
> +	COUNTER_DATA_COUNT_MODE_AND_AVAILABLE(quad8_count_mode_read,
> +					      quad8_count_mode_write,
> +					      quad8_count_mode_available),
> +	COUNTER_DATA_DIRECTION(quad8_direction_read),
> +	COUNTER_DATA_ENABLE(quad8_count_enable_read, quad8_count_enable_write),
> +	COUNTER_DATA_ERROR_NOISE_AND_AVAILABLE(quad8_error_noise_read,
> +					       quad8_error_noise_available_read),
> +	COUNTER_DATA_PRESET(quad8_count_preset_read, quad8_count_preset_write),
> +	COUNTER_DATA_PRESET_ENABLE(quad8_count_preset_enable_read,
> +				   quad8_count_preset_enable_write),
>  };
>  
>  #define QUAD8_COUNT(_id, _cntname) {					\
> @@ -1421,7 +1377,12 @@ static int quad8_probe(struct device *dev, unsigned int id)
>  	quad8iio = iio_priv(indio_dev);
>  	quad8iio->counter.name = dev_name(dev);
>  	quad8iio->counter.parent = dev;
> -	quad8iio->counter.ops = &quad8_ops;
> +	quad8iio->counter.signal_read = quad8_signal_read;
> +	quad8iio->counter.count_read = quad8_count_read;
> +	quad8iio->counter.count_write = quad8_count_write;
> +	quad8iio->counter.function_read = quad8_function_read;
> +	quad8iio->counter.function_write = quad8_function_write;
> +	quad8iio->counter.action_read = quad8_action_read;
>  	quad8iio->counter.counts = quad8_counts;
>  	quad8iio->counter.num_counts = ARRAY_SIZE(quad8_counts);
>  	quad8iio->counter.signals = quad8_signals;
> diff --git a/drivers/counter/Makefile b/drivers/counter/Makefile
> index 55142d1f4c43..2d2644bd7777 100644
> --- a/drivers/counter/Makefile
> +++ b/drivers/counter/Makefile
> @@ -4,6 +4,7 @@
>  #
>  
>  obj-$(CONFIG_COUNTER) += counter.o
> +counter-y := counter-core.o counter-sysfs.o counter-sysfs-callbacks.o
>  
>  obj-$(CONFIG_104_QUAD_8)	+= 104-quad-8.o
>  obj-$(CONFIG_STM32_TIMER_CNT)	+= stm32-timer-cnt.o
> diff --git a/drivers/counter/counter-core.c b/drivers/counter/counter-core.c
> new file mode 100644
> index 000000000000..008d51284a2c
> --- /dev/null
> +++ b/drivers/counter/counter-core.c
> @@ -0,0 +1,190 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Generic Counter interface
> + * Copyright (C) 2020 William Breathitt Gray
> + */
> +#include <linux/counter.h>
> +#include <linux/device.h>
> +#include <linux/err.h>
> +#include <linux/export.h>
> +#include <linux/gfp.h>
> +#include <linux/idr.h>
> +#include <linux/init.h>
> +#include <linux/module.h>
> +#include <linux/slab.h>
> +
> +#include "counter-sysfs.h"
> +
> +/* Provides a unique ID for each counter device */
> +static DEFINE_IDA(counter_ida);
> +
> +static void counter_device_release(struct device *dev)
> +{
> +	struct counter_device *const counter = dev_get_drvdata(dev);
> +
> +	counter_sysfs_free(counter);
> +	kfree(&counter->dev);
> +	ida_simple_remove(&counter_ida, counter->id);
> +}
> +
> +static struct device_type counter_device_type = {
> +	.name = "counter_device",
> +	.release = counter_device_release
> +};
> +
> +static struct bus_type counter_bus_type = {
> +	.name = "counter"
> +};
> +
> +/**
> + * counter_register - register Counter to the system
> + * @counter:	pointer to Counter to register
> + *
> + * This function registers a Counter to the system. A sysfs "counter" directory
> + * will be created and populated with sysfs attributes correlating with the
> + * Counter Signals, Synapses, and Counts respectively.
> + */
> +int counter_register(struct counter_device *const counter)
> +{
> +	struct device *const dev = &counter->dev;
> +	int err;
> +
> +	/* Acquire unique ID */
> +	counter->id = ida_simple_get(&counter_ida, 0, 0, GFP_KERNEL);
> +	if (counter->id < 0)
> +		return counter->id;
> +
> +	/* Configure device structure for Counter */
> +	dev->type = &counter_device_type;
> +	dev->bus = &counter_bus_type;
> +	if (counter->parent) {
> +		dev->parent = counter->parent;
> +		dev->of_node = counter->parent->of_node;
> +	}
> +	dev_set_name(dev, "counter%d", counter->id);
> +	device_initialize(dev);
> +	dev_set_drvdata(dev, counter);
> +
> +	/* Add Counter sysfs attributes */
> +	err = counter_sysfs_add(counter);
> +	if (err)
> +		goto err_free_id;
> +
> +	/* Add device to system */
> +	err = device_add(dev);
> +	if (err)
> +		goto err_free_sysfs;
> +
> +	return 0;
> +
> +err_free_sysfs:
> +	counter_sysfs_free(counter);
> +err_free_id:
> +	ida_simple_remove(&counter_ida, counter->id);
> +	return err;
> +}
> +EXPORT_SYMBOL_GPL(counter_register);
> +
> +/**
> + * counter_unregister - unregister Counter from the system
> + * @counter:	pointer to Counter to unregister
> + *
> + * The Counter is unregistered from the system; all allocated memory is freed.
> + */
> +void counter_unregister(struct counter_device *const counter)
> +{
> +	if (counter) {
> +		device_del(&counter->dev);
> +		counter_sysfs_free(counter);
> +	}
> +}
> +EXPORT_SYMBOL_GPL(counter_unregister);
> +
> +static void devm_counter_unreg(struct device *dev, void *res)
> +{
> +	counter_unregister(*(struct counter_device **)res);
> +}
> +
> +/**
> + * devm_counter_register - Resource-managed counter_register
> + * @dev:	device to allocate counter_device for
> + * @counter:	pointer to Counter to register
> + *
> + * Managed counter_register. The Counter registered with this function is
> + * automatically unregistered on driver detach. This function calls
> + * counter_register internally. Refer to that function for more information.
> + *
> + * If an Counter registered with this function needs to be unregistered
> + * separately, devm_counter_unregister must be used.
> + *
> + * RETURNS:
> + * 0 on success, negative error number on failure.
> + */
> +int devm_counter_register(struct device *dev,
> +			  struct counter_device *const counter)
> +{
> +	struct counter_device **ptr;
> +	int ret;
> +
> +	ptr = devres_alloc(devm_counter_unreg, sizeof(*ptr), GFP_KERNEL);
> +	if (!ptr)
> +		return -ENOMEM;
> +
> +	ret = counter_register(counter);
> +	if (!ret) {
> +		*ptr = counter;
> +		devres_add(dev, ptr);
> +	} else {
> +		devres_free(ptr);
> +	}
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(devm_counter_register);
> +
> +static int devm_counter_match(struct device *dev, void *res, void *data)
> +{
> +	struct counter_device **r = res;
> +
> +	if (!r || !*r) {
> +		WARN_ON(!r || !*r);
> +		return 0;
> +	}
> +
> +	return *r == data;
> +}
> +
> +/**
> + * devm_counter_unregister - Resource-managed counter_unregister

Having just gone through the process of ripping all these out of IIO, is
there actually a valid reason why devm_counter_unregister would ever
be called?  

> + * @dev:	device this counter_device belongs to
> + * @counter:	pointer to Counter associated with the device
> + *
> + * Unregister Counter registered with devm_counter_register.
> + */
> +void devm_counter_unregister(struct device *dev,
> +			     struct counter_device *const counter)
> +{
> +	int rc;
> +
> +	rc = devres_release(dev, devm_counter_unreg, devm_counter_match,
> +			    counter);
> +	WARN_ON(rc);
> +}
> +EXPORT_SYMBOL_GPL(devm_counter_unregister);
> +
> +static int __init counter_init(void)
> +{
> +	return bus_register(&counter_bus_type);
> +}
> +
> +static void __exit counter_exit(void)
> +{
> +	bus_unregister(&counter_bus_type);
> +}
> +
> +subsys_initcall(counter_init);
> +module_exit(counter_exit);
> +
> +MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@...il.com>");
> +MODULE_DESCRIPTION("Generic Counter interface");
> +MODULE_LICENSE("GPL v2");
> diff --git a/drivers/counter/counter-function-types.h b/drivers/counter/counter-function-types.h
> new file mode 100644
> index 000000000000..1a67b3904193
> --- /dev/null
> +++ b/drivers/counter/counter-function-types.h
> @@ -0,0 +1,81 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Counter callback function types
> + * Copyright (C) 2020 William Breathitt Gray
> + */
> +#ifndef _COUNTER_FUNCTION_TYPES_H_
> +#define _COUNTER_FUNCTION_TYPES_H_
> +
> +#include <linux/counter.h>
> +#include <linux/types.h>
> +
> +#define COUNTER_DATA_CALLBACKS(_name, _type) \
> +	typedef int (*counter_count_##_name##_read)(struct counter_device *, \
> +						    struct counter_count *, \
> +						    _type *); \
> +	typedef int (*counter_count_##_name##_write)(struct counter_device *, \
> +						     struct counter_count *, \
> +						     _type); \
> +	typedef int (*counter_device_##_name##_read)(struct counter_device *, \
> +						     _type *); \
> +	typedef int (*counter_device_##_name##_write)(struct counter_device *, \
> +						      _type); \
> +	typedef int (*counter_signal_##_name##_read)(struct counter_device *, \
> +						     struct counter_signal *, \
> +						     _type *); \
> +	typedef int (*counter_signal_##_name##_write)(struct counter_device *, \
> +						      struct counter_signal *, \
> +						      _type)
> +
> +COUNTER_DATA_CALLBACKS(bool, bool);
> +COUNTER_DATA_CALLBACKS(lu, unsigned long);
> +COUNTER_DATA_CALLBACKS(zu, size_t);
> +
> +typedef ssize_t (*counter_count_s_read)(struct counter_device *,
> +					struct counter_count *, char *, size_t);
> +typedef ssize_t (*counter_count_s_write)(struct counter_device *,
> +					 struct counter_count *, const char *,
> +					 size_t);
> +typedef ssize_t (*counter_device_s_read)(struct counter_device *, char *,
> +					 size_t);
> +typedef ssize_t (*counter_device_s_write)(struct counter_device *, const char *,
> +					  size_t);
> +typedef ssize_t (*counter_signal_s_read)(struct counter_device *,
> +					 struct counter_signal *, char *,
> +					 size_t);
> +typedef ssize_t (*counter_signal_s_write)(struct counter_device *,
> +					  struct counter_signal *, const char *,
> +					  size_t);
> +
> +typedef int (*counter_count_function_read)(struct counter_device *,
> +					   struct counter_count *,
> +					   enum counter_count_function *);
> +typedef int (*counter_count_function_write)(struct counter_device *,
> +					    struct counter_count *,
> +					    enum counter_count_function);
> +
> +typedef int (*counter_signal_signal_read)(struct counter_device *,
> +					  struct counter_signal *,
> +					  enum counter_signal_value *);
> +
> +typedef int (*counter_synapse_action_read)(struct counter_device *,
> +					   struct counter_count *,
> +					   struct counter_synapse *,
> +					   enum counter_synapse_action *);
> +typedef int (*counter_synapse_action_write)(struct counter_device *,
> +					    struct counter_count *,
> +					    struct counter_synapse *,
> +					    enum counter_synapse_action);
> +
> +typedef int (*counter_count_direction_read)(struct counter_device *,
> +					    struct counter_count *,
> +					    enum counter_count_direction *);
> +
> +typedef int (*counter_count_mode_read)(struct counter_device *,
> +				       struct counter_count *,
> +				       enum counter_count_mode *);
> +typedef int (*counter_count_mode_write)(struct counter_device *,
> +					struct counter_count *,
> +					enum counter_count_mode);
> +
> +#endif /* _COUNTER_FUNCTION_TYPES_H_ */
> diff --git a/drivers/counter/counter-strings.h b/drivers/counter/counter-strings.h
> new file mode 100644
> index 000000000000..d67788e01bb9
> --- /dev/null
> +++ b/drivers/counter/counter-strings.h

Give you are centralising the handling of these, I'd be a bit surprised to ever
see this included from more than one file.  As such, I'd just put it in the
c files that uses it.

> @@ -0,0 +1,46 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Generic Counter strings
> + * Copyright (C) 2020 William Breathitt Gray
> + */
> +#ifndef _COUNTER_STRINGS_H_
> +#define _COUNTER_STRINGS_H_
> +
> +#include <linux/counter.h>
> +
> +const char *const counter_count_direction_str[] = {
> +	[COUNTER_COUNT_DIRECTION_FORWARD] = "forward",
> +	[COUNTER_COUNT_DIRECTION_BACKWARD] = "backward"
> +};
> +
> +const char *const counter_count_function_str[] = {
> +	[COUNTER_COUNT_FUNCTION_INCREASE] = "increase",
> +	[COUNTER_COUNT_FUNCTION_DECREASE] = "decrease",
> +	[COUNTER_COUNT_FUNCTION_PULSE_DIRECTION] = "pulse-direction",
> +	[COUNTER_COUNT_FUNCTION_QUADRATURE_X1_A] = "quadrature x1 a",
> +	[COUNTER_COUNT_FUNCTION_QUADRATURE_X1_B] = "quadrature x1 b",
> +	[COUNTER_COUNT_FUNCTION_QUADRATURE_X2_A] = "quadrature x2 a",
> +	[COUNTER_COUNT_FUNCTION_QUADRATURE_X2_B] = "quadrature x2 b",
> +	[COUNTER_COUNT_FUNCTION_QUADRATURE_X4] = "quadrature x4"
> +};
> +
> +const char *const counter_count_mode_str[] = {
> +	[COUNTER_COUNT_MODE_NORMAL] = "normal",
> +	[COUNTER_COUNT_MODE_RANGE_LIMIT] = "range limit",
> +	[COUNTER_COUNT_MODE_NON_RECYCLE] = "non-recycle",
> +	[COUNTER_COUNT_MODE_MODULO_N] = "modulo-n"
> +};
> +
> +const char *const counter_signal_value_str[] = {
> +	[COUNTER_SIGNAL_LOW] = "low",
> +	[COUNTER_SIGNAL_HIGH] = "high"
> +};
> +
> +const char *const counter_synapse_action_str[] = {
> +	[COUNTER_SYNAPSE_ACTION_NONE] = "none",
> +	[COUNTER_SYNAPSE_ACTION_RISING_EDGE] = "rising edge",
> +	[COUNTER_SYNAPSE_ACTION_FALLING_EDGE] = "falling edge",
> +	[COUNTER_SYNAPSE_ACTION_BOTH_EDGES] = "both edges"
> +};
> +
> +#endif /* _COUNTER_STRINGS_H_ */
> diff --git a/drivers/counter/counter-sysfs-callbacks.c b/drivers/counter/counter-sysfs-callbacks.c
> new file mode 100644
> index 000000000000..5740d61e999b
> --- /dev/null
> +++ b/drivers/counter/counter-sysfs-callbacks.c
> @@ -0,0 +1,566 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Generic Counter sysfs callbacks
> + * Copyright (C) 2020 William Breathitt Gray
> + */
> +#include <linux/counter.h>
> +#include <linux/device.h>
> +#include <linux/err.h>
> +#include <linux/kernel.h>
> +#include <linux/types.h>
> +#include <linux/string.h>
> +#include <linux/types.h>
> +
> +#include "counter-function-types.h"
> +#include "counter-strings.h"
> +#include "counter-sysfs-callbacks.h"
> +
> +#define to_counter_attribute(_dev_attr) \
> +	container_of(_dev_attr, struct counter_attribute, dev_attr)
> +
> +static ssize_t counter_data_bool_show(struct device *dev,
> +				      struct device_attribute *attr, char *buf)
> +{
> +	const struct counter_attribute *const a = to_counter_attribute(attr);
> +	const counter_count_bool_read count_bool_read = a->data.read;
> +	const counter_device_bool_read device_bool_read = a->data.read;
> +	const counter_signal_bool_read signal_bool_read = a->data.read;

That's not pretty.  Try my union suggestion, then all of the functions
will be typed in the first place.

> +	struct counter_device *const counter = dev_get_drvdata(dev);
> +	void *const owner = a->owner;

Skip having a local copy of a->owner as code will shorter and easier
to follow without.

> +	int err = 0;
> +	bool data;
> +
> +	switch (a->type) {
> +	case COUNTER_OWNER_TYPE_COUNT:
> +		err = count_bool_read(counter, owner, &data);
> +		break;
> +	case COUNTER_OWNER_TYPE_DEVICE:
> +		err = device_bool_read(counter, &data);
> +		break;
> +	case COUNTER_OWNER_TYPE_SIGNAL:
> +		err = signal_bool_read(counter, owner, &data);
> +		break;

As this stands any value of a->type not listed returns no error.

> +	}
> +	if (err)
> +		return err;
> +
> +	return sprintf(buf, "%u\n", (unsigned int)data);
> +}
> +
> +static ssize_t counter_data_bool_store(struct device *dev,
> +				       struct device_attribute *attr,
> +				       const char *buf, size_t len)
> +{
> +	const struct counter_attribute *const a = to_counter_attribute(attr);
> +	const counter_count_bool_write count_bool_write = a->data.write;
> +	const counter_device_bool_write device_bool_write = a->data.write;
> +	const counter_signal_bool_write signal_bool_write = a->data.write;
> +	struct counter_device *const counter = dev_get_drvdata(dev);
> +	void *const owner = a->owner;
> +	int err;
> +	bool data;
> +
> +	err = kstrtobool(buf, &data);
> +	if (err)
> +		return err;
> +
> +	switch (a->type) {
> +	case COUNTER_OWNER_TYPE_COUNT:
> +		err = count_bool_write(counter, owner, data);
> +		break;
> +	case COUNTER_OWNER_TYPE_DEVICE:
> +		err = device_bool_write(counter, data);
> +		break;
> +	case COUNTER_OWNER_TYPE_SIGNAL:
> +		err = signal_bool_write(counter, owner, data);
> +		break;
default:
	return -EINVAL;

> +	}
> +	if (err)
> +		return err;
> +
> +	return len;
> +}
> +
> +static ssize_t counter_data_lu_show(struct device *dev,
> +				    struct device_attribute *attr, char *buf)
> +{
> +	const struct counter_attribute *const a = to_counter_attribute(attr);
> +	const counter_count_lu_read count_lu_read = a->data.read;
> +	const counter_device_lu_read device_lu_read = a->data.read;
> +	const counter_signal_lu_read signal_lu_read = a->data.read;
> +	struct counter_device *const counter = dev_get_drvdata(dev);
> +	void *const owner = a->owner;
> +	int err = 0;
> +	unsigned long data;
> +
> +	switch (a->type) {
> +	case COUNTER_OWNER_TYPE_COUNT:
> +		err = count_lu_read(counter, owner, &data);
> +		break;
> +	case COUNTER_OWNER_TYPE_DEVICE:
> +		err = device_lu_read(counter, &data);
> +		break;
> +	case COUNTER_OWNER_TYPE_SIGNAL:
> +		err = signal_lu_read(counter, owner, &data);
> +		break;
> +	}
> +	if (err)
> +		return err;
> +
> +	return sprintf(buf, "%lu\n", data);
> +}
> +
> +static ssize_t counter_data_lu_store(struct device *dev,
> +				     struct device_attribute *attr,
> +				     const char *buf, size_t len)
> +{
> +	const struct counter_attribute *const a = to_counter_attribute(attr);
> +	const counter_count_lu_write count_lu_write = a->data.write;
> +	const counter_device_lu_write device_lu_write = a->data.write;
> +	const counter_signal_lu_write signal_lu_write = a->data.write;
> +	struct counter_device *const counter = dev_get_drvdata(dev);
> +	void *const owner = a->owner;
> +	int err;
> +	unsigned long data;
> +
> +	err = kstrtoul(buf, 0, &data);
> +	if (err)
> +		return err;
> +
> +	switch (a->type) {
> +	case COUNTER_OWNER_TYPE_COUNT:
> +		err = count_lu_write(counter, owner, data);
> +		break;
> +	case COUNTER_OWNER_TYPE_DEVICE:
> +		err = device_lu_write(counter, data);
> +		break;
> +	case COUNTER_OWNER_TYPE_SIGNAL:
> +		err = signal_lu_write(counter, owner, data);
> +		break;
> +	}
> +	if (err)
> +		return err;
> +
> +	return len;
> +}
> +
> +static ssize_t counter_data_zu_show(struct device *dev,
> +				    struct device_attribute *attr, char *buf)
> +{
> +	const struct counter_attribute *const a = to_counter_attribute(attr);
> +	const counter_device_zu_read zu_read = a->data.read;
> +	struct counter_device *const counter = dev_get_drvdata(dev);
> +	int err;
> +	size_t data;
> +
> +	err = zu_read(counter, &data);
> +	if (err)
> +		return err;
> +
> +	return sprintf(buf, "%zu\n", data);
> +}
> +
> +static ssize_t counter_data_s_show(struct device *dev,
> +				   struct device_attribute *attr, char *buf)
> +{
> +	const struct counter_attribute *const a = to_counter_attribute(attr);
> +	const counter_count_s_read count_s_read = a->data.read;
> +	const counter_device_s_read device_s_read = a->data.read;
> +	const counter_signal_s_read signal_s_read = a->data.read;
> +	struct counter_device *const counter = dev_get_drvdata(dev);
> +	void *const owner = a->owner;
> +
> +	switch (a->type) {
> +	case COUNTER_OWNER_TYPE_COUNT:
> +		return count_s_read(counter, owner, buf, PAGE_SIZE);
> +	case COUNTER_OWNER_TYPE_DEVICE:
> +		return device_s_read(counter, buf, PAGE_SIZE);
> +	case COUNTER_OWNER_TYPE_SIGNAL:
> +		return signal_s_read(counter, owner, buf, PAGE_SIZE);
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +static ssize_t counter_data_s_store(struct device *dev,
> +				    struct device_attribute *attr,
> +				    const char *buf, size_t len)
> +{
> +	const struct counter_attribute *const a = to_counter_attribute(attr);
> +	const counter_count_s_write count_s_write = a->data.write;
> +	const counter_device_s_write device_s_write = a->data.write;
> +	const counter_signal_s_write signal_s_write = a->data.write;
> +	struct counter_device *const counter = dev_get_drvdata(dev);
> +	void *const owner = a->owner;
> +
> +	switch (a->type) {
> +	case COUNTER_OWNER_TYPE_COUNT:
> +		return count_s_write(counter, owner, buf, len);
> +	case COUNTER_OWNER_TYPE_DEVICE:
> +		return device_s_write(counter, buf, len);
> +	case COUNTER_OWNER_TYPE_SIGNAL:
> +		return signal_s_write(counter, owner, buf, len);
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +static ssize_t counter_data_count_function_show(struct device *dev,
> +						struct device_attribute *attr,
> +						char *buf)
> +{
> +	const struct counter_attribute *const a = to_counter_attribute(attr);
> +	const counter_count_function_read function_read = a->data.read;
> +	struct counter_device *const counter = dev_get_drvdata(dev);
> +	struct counter_count *const count = a->owner;
> +	int err;
> +	enum counter_count_function function;
> +
> +	err = function_read(counter, count, &function);
> +	if (err)
> +		return err;
> +
> +	return sprintf(buf, "%s\n", counter_count_function_str[function]);
> +}
> +
> +static ssize_t counter_data_count_function_store(struct device *dev,
> +						 struct device_attribute *attr,
> +						 const char *buf, size_t len)
> +{
> +	const struct counter_attribute *const a = to_counter_attribute(attr);
> +	const counter_count_function_write function_write = a->data.write;
> +	struct counter_device *const counter = dev_get_drvdata(dev);
> +	struct counter_count *const count = a->owner;
> +	const size_t num_functions = count->num_functions;
> +	int err;
> +	size_t index;
> +	enum counter_count_function function;
> +
> +	/* Find requested function mode */
> +	for (index = 0; index < num_functions; index++) {
> +		function = count->functions_list[index];
> +		if (sysfs_streq(buf, counter_count_function_str[function]))
> +			break;
> +	}
> +	/* If requested function mode not found */
> +	if (index >= num_functions)
> +		return -EINVAL;
> +
> +	err = function_write(counter, count, function);
> +	if (err)
> +		return err;
> +
> +	return len;
> +}
> +
> +static ssize_t counter_data_count_function_available_show(struct device *dev,
> +	struct device_attribute *attr, char *buf)
> +{
> +	const struct counter_attribute *const a = to_counter_attribute(attr);
> +	const struct counter_count *const count = a->owner;
> +	size_t i;
> +	enum counter_count_function function;
> +	ssize_t len = 0;
> +
> +	for (i = 0; i < count->num_functions; i++) {
> +		function = count->functions_list[i];
> +		len += sprintf(buf + len, "%s\n",
> +			       counter_count_function_str[function]);
> +	}
> +
> +	return len;
> +}
> +
> +static ssize_t counter_data_signal_show(struct device *dev,
> +					struct device_attribute *attr,
> +					char *buf)
> +{
> +	const struct counter_attribute *const a = to_counter_attribute(attr);
> +	const counter_signal_signal_read signal_read = a->data.read;
> +	struct counter_device *const counter = dev_get_drvdata(dev);
> +	struct counter_signal *const signal = a->owner;
> +	int err;
> +	enum counter_signal_value value;
> +
> +	err = signal_read(counter, signal, &value);
> +	if (err)
> +		return err;
> +
> +	return sprintf(buf, "%s\n", counter_signal_value_str[value]);
> +}
> +
> +static ssize_t counter_data_synapse_action_show(struct device *dev,
> +						struct device_attribute *attr,
> +						char *buf)
> +{
> +	const struct counter_attribute *const a = to_counter_attribute(attr);
> +	const counter_synapse_action_read action_read = a->data.read;
> +	struct counter_device *const counter = dev_get_drvdata(dev);
> +	struct counter_count *const count = a->owner;
> +	struct counter_synapse *const synapse = a->data.priv;
> +	int err;
> +	enum counter_synapse_action action;
> +
> +	err = action_read(counter, count, synapse, &action);
> +	if (err)
> +		return err;
> +
> +	return sprintf(buf, "%s\n", counter_synapse_action_str[action]);
> +}
> +
> +static ssize_t counter_data_synapse_action_store(struct device *dev,
> +						 struct device_attribute *attr,
> +						 const char *buf, size_t len)
> +{
> +	const struct counter_attribute *const a = to_counter_attribute(attr);
> +	const counter_synapse_action_write action_write = a->data.write;
> +	struct counter_device *const counter = dev_get_drvdata(dev);
> +	struct counter_count *const count = a->owner;
> +	struct counter_synapse *const synapse = a->data.priv;
> +	const size_t num_actions = synapse->num_actions;
> +	int err;
> +	size_t index;
> +	enum counter_synapse_action action;
> +
> +	/* Find requested action mode */
> +	for (index = 0; index < num_actions; index++) {
> +		action = synapse->actions_list[index];
> +		if (sysfs_streq(buf, counter_synapse_action_str[action]))
> +			break;
> +	}
> +	/* If requested action mode not found */
> +	if (index >= num_actions)
> +		return -EINVAL;
> +
> +	err = action_write(counter, count, synapse, action);
> +	if (err)
> +		return err;
> +
> +	return len;
> +}
> +
> +static ssize_t counter_data_synapse_action_available_show(struct device *dev,
> +	struct device_attribute *attr, char *buf)
> +{
> +	const struct counter_attribute *const a = to_counter_attribute(attr);
> +	const struct counter_synapse *const synapse = a->data.priv;
> +	size_t i;
> +	enum counter_synapse_action action;
> +	ssize_t len = 0;
> +
> +	for (i = 0; i < synapse->num_actions; i++) {
> +		action = synapse->actions_list[i];
> +		len += sprintf(buf + len, "%s\n",
> +			       counter_synapse_action_str[action]);
> +	}
> +
> +	return len;
> +}
> +
> +static ssize_t counter_data_enum_show(struct device *dev,
> +				      struct device_attribute *attr, char *buf)
> +{
> +	const struct counter_attribute *const a = to_counter_attribute(attr);
> +	const counter_count_zu_read count_enum_read = a->data.read;
> +	const counter_device_zu_read device_enum_read = a->data.read;
> +	const counter_signal_zu_read signal_enum_read = a->data.read;
> +	struct counter_device *const counter = dev_get_drvdata(dev);
> +	void *const owner = a->owner;
> +	struct counter_enum *const cntr_enum = a->data.priv;
> +	int err = 0;
> +	size_t index;
> +
> +	switch (a->type) {
> +	case COUNTER_OWNER_TYPE_COUNT:
> +		err = count_enum_read(counter, owner, &index);
> +		break;
> +	case COUNTER_OWNER_TYPE_DEVICE:
> +		err = device_enum_read(counter, &index);
> +		break;
> +	case COUNTER_OWNER_TYPE_SIGNAL:
> +		err = signal_enum_read(counter, owner, &index);
> +		break;
> +	}
> +	if (err)
> +		return err;
> +
> +	if (index >= cntr_enum->num_items)
> +		return -EINVAL;
> +
> +	return sprintf(buf, "%s\n", cntr_enum->items[index]);
> +}
> +
> +static ssize_t counter_data_enum_store(struct device *dev,
> +				       struct device_attribute *attr,
> +				       const char *buf, size_t len)
> +{
> +	const struct counter_attribute *const a = to_counter_attribute(attr);
> +	struct counter_enum *const cntr_enum = a->data.priv;
> +	const size_t num_items = cntr_enum->num_items;
> +	const counter_count_zu_write count_enum_write = a->data.write;
> +	const counter_device_zu_write device_enum_write = a->data.write;
> +	const counter_signal_zu_write signal_enum_write = a->data.write;
> +	struct counter_device *const counter = dev_get_drvdata(dev);
> +	void *const owner = a->owner;
> +	ssize_t index;
> +	int err = 0;
> +
> +	index = __sysfs_match_string(cntr_enum->items, num_items, buf);
> +	if (index < 0)
> +		return index;
> +
> +	switch (a->type) {
> +	case COUNTER_OWNER_TYPE_COUNT:
> +		err = count_enum_write(counter, owner, index);
> +		break;
> +	case COUNTER_OWNER_TYPE_DEVICE:
> +		err = device_enum_write(counter, index);
> +		break;
> +	case COUNTER_OWNER_TYPE_SIGNAL:
> +		err = signal_enum_write(counter, owner, index);
> +		break;
> +	}
> +	if (err)
> +		return err;
> +
> +	return len;
> +}
> +
> +static ssize_t counter_data_enum_available_show(struct device *dev,
> +						struct device_attribute *attr,
> +						char *buf)
> +{
> +	const struct counter_attribute *const a = to_counter_attribute(attr);
> +	struct counter_enum *const cntr_enum = a->data.priv;
> +	size_t i;
> +	size_t len = 0;
> +
> +	for (i = 0; i < cntr_enum->num_items; i++)
> +		len += sprintf(buf + len, "%s\n", cntr_enum->items[i]);
> +
> +	return len;
> +}
> +
> +static ssize_t counter_data_count_direction_show(struct device *dev,
> +						 struct device_attribute *attr,
> +						 char *buf)
> +{
> +	const struct counter_attribute *const a = to_counter_attribute(attr);
> +	const counter_count_direction_read direction_read = a->data.read;
> +	struct counter_device *const counter = dev_get_drvdata(dev);
> +	struct counter_count *const count = a->owner;
> +	int err;
> +	enum counter_count_direction direction;
> +
> +	err = direction_read(counter, count, &direction);
> +	if (err)
> +		return err;
> +
> +	return sprintf(buf, "%s\n", counter_count_direction_str[direction]);
> +}
> +
> +static ssize_t counter_data_count_mode_show(struct device *dev,
> +					    struct device_attribute *attr,
> +					    char *buf)
> +{
> +	const struct counter_attribute *const a = to_counter_attribute(attr);
> +	const counter_count_mode_read count_mode_read = a->data.read;
> +	struct counter_device *const counter = dev_get_drvdata(dev);
> +	struct counter_count *const count = a->owner;
> +	int err;
> +	enum counter_count_mode count_mode;
> +
> +	err = count_mode_read(counter, count, &count_mode);
> +	if (err)
> +		return err;
> +
> +	return sprintf(buf, "%s\n", counter_count_mode_str[count_mode]);
> +}
> +
> +static ssize_t counter_data_count_mode_store(struct device *dev,
> +					     struct device_attribute *attr,
> +					     const char *buf, size_t len)
> +{
> +	const struct counter_attribute *const a = to_counter_attribute(attr);
> +	const counter_count_mode_write count_mode_write = a->data.write;
> +	struct counter_device *const counter = dev_get_drvdata(dev);
> +	struct counter_count *const count = a->owner;
> +	const struct counter_available *const available = a->data.priv;
> +	const enum counter_count_mode *const items = available->items;
> +	const size_t num_count_modes = available->num_items;
> +	int err;
> +	size_t index;
> +	enum counter_count_mode count_mode;
> +
> +	/* Find requested count mode */
> +	for (index = 0; index < num_count_modes; index++) {
> +		count_mode = items[index];
> +		if (sysfs_streq(buf, counter_count_mode_str[count_mode]))
> +			break;
> +	}
> +	/* If requested count mode not found */
> +	if (index >= num_count_modes)
> +		return -EINVAL;
> +
> +	err = count_mode_write(counter, count, count_mode);
> +	if (err)
> +		return err;
> +
> +	return len;
> +}
> +
> +static ssize_t counter_data_count_mode_available_show(struct device *dev,
> +	struct device_attribute *attr, char *buf)
> +{
> +	const struct counter_attribute *const a = to_counter_attribute(attr);
> +	const struct counter_available *const available = a->data.priv;
> +	const enum counter_count_mode *const items = available->items;
> +	size_t i;
> +	enum counter_count_mode count_mode;
> +	ssize_t len = 0;
> +
> +	for (i = 0; i < available->num_items; i++) {
> +		count_mode = items[i];
> +		len += sprintf(buf + len, "%s\n",
> +			       counter_count_mode_str[count_mode]);
> +	}
> +
> +	return len;
> +}
> +
> +ssize_t (*counter_data_sysfs_show[])(struct device *, struct device_attribute *,
> +				     char *) = {
> +	[COUNTER_DATA_TYPE_BOOL] = counter_data_bool_show,
> +	[COUNTER_DATA_TYPE_UNSIGNED_LONG] = counter_data_lu_show,
> +	[COUNTER_DATA_TYPE_SIZE] = counter_data_zu_show,
> +	[COUNTER_DATA_TYPE_STRING] = counter_data_s_show,
> +	[COUNTER_DATA_TYPE_COUNT_FUNCTION] = counter_data_count_function_show,
> +	[COUNTER_DATA_TYPE_COUNT_FUNCTION_AVAILABLE] = counter_data_count_function_available_show,
> +	[COUNTER_DATA_TYPE_SIGNAL] = counter_data_signal_show,
> +	[COUNTER_DATA_TYPE_SYNAPSE_ACTION] = counter_data_synapse_action_show,
> +	[COUNTER_DATA_TYPE_SYNAPSE_ACTION_AVAILABLE] = counter_data_synapse_action_available_show,
> +	[COUNTER_DATA_TYPE_ENUM] = counter_data_enum_show,
> +	[COUNTER_DATA_TYPE_ENUM_AVAILABLE] = counter_data_enum_available_show,
> +	[COUNTER_DATA_TYPE_COUNT_DIRECTION] = counter_data_count_direction_show,
> +	[COUNTER_DATA_TYPE_COUNT_MODE] = counter_data_count_mode_show,
> +	[COUNTER_DATA_TYPE_COUNT_MODE_AVAILABLE] = counter_data_count_mode_available_show,
> +};
> +
> +ssize_t (*counter_data_sysfs_store[])(struct device *,
> +				      struct device_attribute *, const char *,
> +				      size_t) = {
> +	[COUNTER_DATA_TYPE_BOOL] = counter_data_bool_store,
> +	[COUNTER_DATA_TYPE_UNSIGNED_LONG] = counter_data_lu_store,
> +	[COUNTER_DATA_TYPE_SIZE] = NULL,
> +	[COUNTER_DATA_TYPE_STRING] = counter_data_s_store,
> +	[COUNTER_DATA_TYPE_COUNT_FUNCTION] = counter_data_count_function_store,
> +	[COUNTER_DATA_TYPE_COUNT_FUNCTION_AVAILABLE] = NULL,
> +	[COUNTER_DATA_TYPE_SIGNAL] = NULL,
> +	[COUNTER_DATA_TYPE_SYNAPSE_ACTION] = counter_data_synapse_action_store,
> +	[COUNTER_DATA_TYPE_SYNAPSE_ACTION_AVAILABLE] = NULL,
> +	[COUNTER_DATA_TYPE_ENUM] = counter_data_enum_store,
> +	[COUNTER_DATA_TYPE_ENUM_AVAILABLE] = NULL,
> +	[COUNTER_DATA_TYPE_COUNT_DIRECTION] = NULL,
> +	[COUNTER_DATA_TYPE_COUNT_MODE] = counter_data_count_mode_store,
> +	[COUNTER_DATA_TYPE_COUNT_MODE_AVAILABLE] = NULL,
> +};
> diff --git a/drivers/counter/counter-sysfs-callbacks.h b/drivers/counter/counter-sysfs-callbacks.h
> new file mode 100644
> index 000000000000..cf44e7c6ed18
> --- /dev/null
> +++ b/drivers/counter/counter-sysfs-callbacks.h
> @@ -0,0 +1,28 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Generic Counter sysfs callbacks
> + * Copyright (C) 2020 William Breathitt Gray
> + */
> +#ifndef _COUNTER_SYSFS_CALLBACKS_H_
> +#define _COUNTER_SYSFS_CALLBACKS_H_
> +
> +#include <linux/counter.h>
> +#include <linux/types.h>
> +
> +struct counter_attribute {
> +	struct device_attribute dev_attr;
> +	struct list_head l;
> +
> +	struct counter_data data;
> +	enum counter_owner_type type;
> +	void *owner;
> +};
> +
> +extern ssize_t (*counter_data_sysfs_show[])(struct device *,
> +					    struct device_attribute *, char *);
> +
> +extern ssize_t (*counter_data_sysfs_store[])(struct device *,
> +					     struct device_attribute *,
> +					     const char *, size_t);
> +
> +#endif /* _COUNTER_SYSFS_CALLBACKS_H_ */
> diff --git a/drivers/counter/counter-sysfs.c b/drivers/counter/counter-sysfs.c
> new file mode 100644
> index 000000000000..ed56c6b52490
> --- /dev/null
> +++ b/drivers/counter/counter-sysfs.c
> @@ -0,0 +1,524 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Generic Counter sysfs interface
> + * Copyright (C) 2020 William Breathitt Gray
> + */
> +#include <linux/counter.h>
> +#include <linux/device.h>
> +#include <linux/err.h>
> +#include <linux/gfp.h>
> +#include <linux/kernel.h>
> +#include <linux/list.h>
> +#include <linux/slab.h>
> +#include <linux/sysfs.h>
> +#include <linux/types.h>
> +
> +#include "counter-sysfs-callbacks.h"
> +
> +static int counter_attribute_create(struct counter_attribute_group *const group,
> +				    const struct counter_data *const data,
> +				    const enum counter_owner_type type,
> +				    void *const owner)
> +{
> +	struct counter_attribute *counter_attr;
> +	struct device_attribute *dev_attr;
> +
> +	/* Allocate and initialize Counter attribute */
> +	counter_attr = kzalloc(sizeof(*counter_attr), GFP_KERNEL);
> +	if (!counter_attr)
> +		return -ENOMEM;
> +	counter_attr->data = *data;
> +	counter_attr->type = type;
> +	counter_attr->owner = owner;
> +
> +	/* Configure device attribute */
> +	dev_attr = &counter_attr->dev_attr;
> +	sysfs_attr_init(&dev_attr->attr);
> +	dev_attr->attr.name = data->name;
> +	if (data->read) {
> +		dev_attr->attr.mode |= 0444;
> +		dev_attr->show = counter_data_sysfs_show[data->type];
> +	}
> +	if (data->write) {
> +		dev_attr->attr.mode |= 0200;
> +		dev_attr->store = counter_data_sysfs_store[data->type];
> +	}
> +
> +	/* Keep track of the attribute for later cleanup */
> +	list_add(&counter_attr->l, &group->attr_list);
> +	group->num_attr++;
> +
> +	return 0;
> +}
> +
> +static struct counter_data counter_signal_data = {
> +	.type = COUNTER_DATA_TYPE_SIGNAL,
> +	.name = "signal",
> +};
> +
> +static struct counter_data counter_name_data =
> +	COUNTER_DATA_STRING("name", NULL, NULL);
> +
> +static ssize_t counter_signal_name_read(struct counter_device *counter,
> +					struct counter_signal *signal,
> +					char *buf, size_t size)
> +{
> +	return snprintf(buf, size, "%s\n", signal->name);
> +}
> +
> +static int counter_signal_attributes_create(
> +	struct counter_attribute_group *const group,
> +	struct counter_signal *const signal, void *const signal_read)
> +{
> +	const enum counter_owner_type type = COUNTER_OWNER_TYPE_SIGNAL;
> +	int err;
> +	struct counter_data data;
> +	size_t i;
> +	const struct counter_data *ext;
> +
> +	/* Create main Signal attribute */
> +	data = counter_signal_data;
> +	data.read = signal_read;
> +	err = counter_attribute_create(group, &data, type, signal);
> +	if (err)
> +		return err;
> +
> +	/* Create Signal name attribute */
> +	data = counter_name_data;
> +	data.read = counter_signal_name_read;
> +	err = counter_attribute_create(group, &data, type, signal);
> +	if (err)
> +		return err;
> +
> +	/* Create an attribute for each extension */
> +	for (i = 0; i < signal->num_ext; i++) {
> +		ext = signal->ext + i;
> +		err = counter_attribute_create(group, ext, type, signal);
> +		if (err)
> +			return err;
> +	}
> +
> +	return 0;
> +}
> +
> +static int counter_signals_register(
> +	struct counter_attribute_group *const groups_list,
> +	const struct counter_device *const counter)
> +{
> +	void *const signal_read = counter->signal_read;
> +	size_t i;
> +	struct counter_signal *signal;
> +	const char *name;
> +	int err;
> +
> +	/* Register each Signal */
> +	for (i = 0; i < counter->num_signals; i++) {
> +		signal = counter->signals + i;
> +
> +		/* Generate Signal attribute directory name */
> +		name = kasprintf(GFP_KERNEL, "signal%d", signal->id);
> +		if (!name)
> +			return -ENOMEM;
> +		groups_list[i].attr_group.name = name;
> +
> +		/* Create all attributes associated with Signal */
> +		err = counter_signal_attributes_create(groups_list + i, signal,
> +						       signal_read);
> +		if (err)
> +			return err;
> +	}
> +
> +	return 0;
> +}
> +
> +struct counter_synapse_name {
> +	struct list_head l;
> +	const char *name;
> +};
> +
> +static int counter_synapses_register(
> +	struct counter_attribute_group *const group,
> +	struct counter_device *const counter, struct counter_count *const count)
> +{
> +	const enum counter_owner_type type = COUNTER_OWNER_TYPE_COUNT;
> +	size_t i;
> +	struct counter_synapse *synapse;
> +	int id;
> +	struct counter_synapse_name *name;
> +	struct counter_data data;
> +	int err;
> +
> +	/* Register each Synapse */
> +	for (i = 0; i < count->num_synapses; i++) {
> +		synapse = count->synapses + i;
> +		id = synapse->signal->id;
> +
> +		/* Generate Synapse name list item */
> +		name = kmalloc(sizeof(*name), GFP_KERNEL);
> +		if (!name)
> +			return -ENOMEM;
> +		list_add(&name->l, &counter->synapse_names_list);
> +
> +		/* Generate Synapse action name */
> +		name->name = kasprintf(GFP_KERNEL, "signal%d_action", id);
> +		if (!name->name)
> +			return -ENOMEM;
> +
> +		/* Create action attribute */
> +		data.type = COUNTER_DATA_TYPE_SYNAPSE_ACTION;
> +		data.name = name->name;
> +		data.read = counter->action_read;
> +		data.write = counter->action_write;
> +		data.priv = synapse;
> +		err = counter_attribute_create(group, &data, type, count);
> +		if (err)
> +			return err;
> +
> +		/* Generate Synapse action_available name */
> +		name->name = kasprintf(GFP_KERNEL, "signal%d_action_available",
> +				       id);
> +		if (!name->name)
> +			return -ENOMEM;
> +
> +		/* Create action_available attribute */
> +		data.type = COUNTER_DATA_TYPE_SYNAPSE_ACTION_AVAILABLE;
> +		data.name = name->name;
> +		data.read = counter->action_read;
> +		data.priv = synapse;
> +		err = counter_attribute_create(group, &data, type, count);
> +		if (err)
> +			return err;
> +	}
> +
> +	return 0;
> +}
> +
> +static struct counter_data counter_count_data =
> +	COUNTER_DATA_UNSIGNED_LONG("count", NULL, NULL);
> +
> +static ssize_t counter_count_name_read(struct counter_device *counter,
> +				       struct counter_count *count, char *buf,
> +				       size_t size)
> +{
> +	return snprintf(buf, size, "%s\n", count->name);
> +}
> +
> +static struct counter_data counter_count_function_data = {
> +	.type = COUNTER_DATA_TYPE_COUNT_FUNCTION,
> +	.name = "function",
> +};
> +
> +static struct counter_data counter_count_function_available_data = {
> +	.type = COUNTER_DATA_TYPE_COUNT_FUNCTION_AVAILABLE,
> +	.name = "function_available",
> +};
> +
> +static int counter_count_attributes_create(
> +	struct counter_attribute_group *const group,
> +	const struct counter_device *const counter,
> +	struct counter_count *const count)
> +{
> +	const enum counter_owner_type type = COUNTER_OWNER_TYPE_COUNT;
> +	int err;
> +	struct counter_data data;
> +	size_t i;
> +	const struct counter_data *ext;
> +
> +	/* Create main Count attribute */
> +	data = counter_count_data;
> +	data.read = counter->count_read;
> +	data.write = counter->count_write;
> +	err = counter_attribute_create(group, &data, type, count);
> +	if (err)
> +		return err;
> +
> +	/* Create Count name attribute */
> +	data = counter_name_data;
> +	data.read = counter_count_name_read;
> +	err = counter_attribute_create(group, &data, type, count);
> +	if (err)
> +		return err;
> +
> +	/* Create Count function attribute */
> +	data = counter_count_function_data;
> +	data.read = counter->function_read;
> +	data.write = counter->function_write;
> +	err = counter_attribute_create(group, &data, type, count);
> +	if (err)
> +		return err;
> +
> +	/* Create Count function_available attribute */
> +	data = counter_count_function_available_data;
> +	data.read = counter->function_read;
> +	err = counter_attribute_create(group, &data, type, count);
> +	if (err)
> +		return err;
> +
> +	/* Create an attribute for each extension */
> +	for (i = 0; i < count->num_ext; i++) {
> +		ext = count->ext + i;
> +		err = counter_attribute_create(group, ext, type, count);
> +		if (err)
> +			return err;
> +	}
> +
> +	return 0;
> +}
> +
> +static int counter_counts_register(
> +	struct counter_attribute_group *const groups_list,
> +	struct counter_device *const counter)
> +{
> +	size_t i;
> +	struct counter_count *count;
> +	const char *name;
> +	int err;
> +
> +	/* Register each Count */
> +	for (i = 0; i < counter->num_counts; i++) {
> +		count = counter->counts + i;
> +
> +		/* Generate Count attribute directory name */
> +		name = kasprintf(GFP_KERNEL, "count%d", count->id);
> +		if (!name)
> +			return -ENOMEM;
> +		groups_list[i].attr_group.name = name;
> +
> +		/* Register the Synapses associated with each Count */
> +		err = counter_synapses_register(groups_list + i, counter,
> +						count);
> +		if (err)
> +			return err;
> +
> +		/* Create all attributes associated with Count */
> +		err = counter_count_attributes_create(groups_list + i, counter,
> +						      count);
> +		if (err)
> +			return err;
> +	}
> +
> +	return 0;
> +}
> +
> +static ssize_t counter_name_read(struct counter_device *counter, char *buf,
> +				 size_t size)
> +{
> +	return snprintf(buf, size, "%s\n", counter->name);
> +}
> +
> +static int counter_num_signals_read(struct counter_device *counter, size_t *val)
> +{
> +	*val = counter->num_signals;
> +	return 0;
> +}
> +
> +static int counter_num_counts_read(struct counter_device *counter, size_t *val)
> +{
> +	*val = counter->num_counts;
> +	return 0;
> +}
> +
> +#define COUNTER_DATA_SIZE(_name, _read) \
> +{ \
> +	.type = COUNTER_DATA_TYPE_SIZE, \
> +	.name = (_name), \
> +	.read = (_read), \
> +}
> +
> +static struct counter_data counter_num_signals_data =
> +	COUNTER_DATA_SIZE("num_signals", counter_num_signals_read);
> +
> +static struct counter_data counter_num_counts_data =
> +	COUNTER_DATA_SIZE("num_counts", counter_num_counts_read);
> +
> +static void counter_groups_list_free(struct counter_device *const counter)
> +{
> +	struct counter_attribute_group *group;
> +	struct counter_attribute *p, *n;
> +
> +	/* Loop through all attribute groups (signals, counts, device, etc.) */
> +	while (counter->num_groups--) {
> +		group = counter->groups_list + counter->num_groups;
> +
> +		/* Free all attribute group and associated attributes memory */
> +		kfree(group->attr_group.name);
> +		kfree(group->attr_group.attrs);
> +
> +		/* Free attribute list */
> +		list_for_each_entry_safe(p, n, &group->attr_list, l)
> +			kfree(p);
> +	}
> +
> +	kfree(counter->groups_list);
> +}
> +
> +static int counter_device_register(struct counter_attribute_group *group,
> +				   struct counter_device *const counter)
> +{
> +	const enum counter_owner_type type = COUNTER_OWNER_TYPE_DEVICE;
> +	struct counter_data data;
> +	int err;
> +	size_t i;
> +	const struct counter_data *ext;
> +
> +	/* Register Signals */
> +	err = counter_signals_register(group, counter);
> +	if (err)
> +		goto err_free_groups_list;
> +	group += counter->num_signals;
> +
> +	/* Register Counts and respective Synapses */
> +	err = counter_counts_register(group, counter);
> +	if (err)
> +		goto err_free_groups_list;
> +	group += counter->num_counts;
> +
> +	/* Create name attribute */
> +	data = counter_name_data;
> +	data.read = counter_name_read;
> +	err = counter_attribute_create(group, &data, type, NULL);
> +	if (err)
> +		goto err_free_groups_list;
> +
> +	/* Create num_signals attribute */
> +	data = counter_num_signals_data;
> +	err = counter_attribute_create(group, &data, type, NULL);
> +	if (err)
> +		goto err_free_groups_list;
> +
> +	/* Create num_counts attribute */
> +	data = counter_num_counts_data;
> +	err = counter_attribute_create(group, &data, type, NULL);
> +	if (err)
> +		goto err_free_groups_list;
> +
> +	/* Create an attribute for each extension */
> +	for (i = 0; i < counter->num_ext; i++) {
> +		ext = counter->ext + i;
> +		err = counter_attribute_create(group, ext, type, NULL);
> +		if (err)
> +			goto err_free_groups_list;
> +	}
> +
> +	return 0;
> +
> +err_free_groups_list:
> +	counter_groups_list_free(counter);
> +	return err;
> +}
> +
> +static int counter_groups_list_prepare(struct counter_device *const counter)
> +{
> +	const size_t num_grps = counter->num_signals + counter->num_counts + 1;
> +	struct counter_attribute_group *groups_list;
> +	size_t i;
> +	int err;
> +
> +	/* Allocate space for attribute groups (signals, counts, and ext) */
> +	groups_list = kcalloc(num_grps, sizeof(*groups_list), GFP_KERNEL);
> +	if (!groups_list)
> +		return -ENOMEM;
> +
> +	/* Store groups_list in counter structure */
> +	counter->groups_list = groups_list;
> +	counter->num_groups = num_grps;
> +
> +	/* Initialize attribute lists */
> +	for (i = 0; i < num_grps; i++)
> +		INIT_LIST_HEAD(&groups_list[i].attr_list);
> +
> +	/* Register Counter device attributes */
> +	err = counter_device_register(groups_list, counter);
> +	if (err)
> +		return err;

return counter_device_register...


> +
> +	return 0;
> +}
> +
> +static int counter_groups_prepare(struct counter_device *const counter)
> +{
> +	size_t i, j;
> +	struct counter_attribute_group *group;
> +	struct attribute **attrs;
> +	int err;
> +	struct counter_attribute *p;
> +
> +	/* Allocate attribute groups for association with device */
> +	counter->groups = kcalloc(counter->num_groups + 1,
> +				  sizeof(*counter->groups), GFP_KERNEL);
> +	if (!counter->groups)
> +		return -ENOMEM;
> +
> +	/* Prepare each group of attributes for association */
> +	for (i = 0; i < counter->num_groups; i++) {
> +		group = counter->groups_list + i;
> +
> +		/* Allocate space for attribute pointers */
> +		attrs = kcalloc(group->num_attr + 1, sizeof(*attrs),
> +				GFP_KERNEL);
> +		if (!attrs) {
> +			err = -ENOMEM;
> +			goto err_free_groups;
> +		}
> +		group->attr_group.attrs = attrs;
> +
> +		/* Add attribute pointers to attribute group */
> +		j = 0;
> +		list_for_each_entry(p, &group->attr_list, l)
> +			attrs[j++] = &p->dev_attr.attr;
> +
> +		/* Group attributes in attribute group */
> +		counter->groups[i] = &group->attr_group;
> +	}
> +	/* Associate attributes with device */
> +	counter->dev.groups = counter->groups;
> +
> +	return 0;
> +
> +err_free_groups:
> +	kfree(counter->groups);
> +	return err;
> +}
> +
> +static void counter_synapse_names_free(struct list_head *const names_list)
> +{
> +	struct counter_synapse_name *p, *n;
> +
> +	list_for_each_entry_safe(p, n, names_list, l) {
> +		kfree(p->name);
> +		kfree(p);
> +	}
> +}
> +
> +int counter_sysfs_add(struct counter_device *const counter)
> +{
> +	int err;
> +
> +	/* Initialize Synapse names list */
> +	INIT_LIST_HEAD(&counter->synapse_names_list);
> +
> +	/* Prepare device attributes */
> +	err = counter_groups_list_prepare(counter);
> +	if (err)
> +		goto err_free_synapse_names;
> +
> +	/* Organize device attributes to groups and match to device */
> +	err = counter_groups_prepare(counter);
> +	if (err)
> +		goto err_free_groups_list;
> +
> +	return 0;
> +
> +err_free_groups_list:
> +	counter_groups_list_free(counter);
> +err_free_synapse_names:
> +	counter_synapse_names_free(&counter->synapse_names_list);
> +	return err;
> +}
> +
> +void counter_sysfs_free(struct counter_device *const counter)
> +{
> +	kfree(counter->groups);
> +	counter_groups_list_free(counter);
> +	counter_synapse_names_free(&counter->synapse_names_list);
> +}
> diff --git a/drivers/counter/counter-sysfs.h b/drivers/counter/counter-sysfs.h
> new file mode 100644
> index 000000000000..00e7cd6ea083
> --- /dev/null
> +++ b/drivers/counter/counter-sysfs.h
> @@ -0,0 +1,14 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Counter sysfs interface
> + * Copyright (C) 2020 William Breathitt Gray
> + */
> +#ifndef _COUNTER_SYSFS_H_
> +#define _COUNTER_SYSFS_H_
> +
> +#include <linux/counter.h>
> +
> +int counter_sysfs_add(struct counter_device *const counter);
> +void counter_sysfs_free(struct counter_device *const counter);
> +
> +#endif /* _COUNTER_SYSFS_H_ */
> diff --git a/drivers/counter/counter.c b/drivers/counter/counter.c
> deleted file mode 100644
> index 6a683d086008..000000000000
> --- a/drivers/counter/counter.c
> +++ /dev/null
> @@ -1,1496 +0,0 @@
> -// SPDX-License-Identifier: GPL-2.0
> -/*
> - * Generic Counter interface
> - * Copyright (C) 2018 William Breathitt Gray
> - */
> -#include <linux/counter.h>
> -#include <linux/device.h>
> -#include <linux/err.h>
> -#include <linux/export.h>
> -#include <linux/fs.h>
> -#include <linux/gfp.h>
> -#include <linux/idr.h>
> -#include <linux/init.h>
> -#include <linux/kernel.h>
> -#include <linux/list.h>
> -#include <linux/module.h>
> -#include <linux/printk.h>
> -#include <linux/slab.h>
> -#include <linux/string.h>
> -#include <linux/sysfs.h>
> -#include <linux/types.h>
> -
> -const char *const counter_count_direction_str[2] = {
> -	[COUNTER_COUNT_DIRECTION_FORWARD] = "forward",
> -	[COUNTER_COUNT_DIRECTION_BACKWARD] = "backward"
> -};
> -EXPORT_SYMBOL_GPL(counter_count_direction_str);
> -
> -const char *const counter_count_mode_str[4] = {
> -	[COUNTER_COUNT_MODE_NORMAL] = "normal",
> -	[COUNTER_COUNT_MODE_RANGE_LIMIT] = "range limit",
> -	[COUNTER_COUNT_MODE_NON_RECYCLE] = "non-recycle",
> -	[COUNTER_COUNT_MODE_MODULO_N] = "modulo-n"
> -};
> -EXPORT_SYMBOL_GPL(counter_count_mode_str);
> -
> -ssize_t counter_signal_enum_read(struct counter_device *counter,
> -				 struct counter_signal *signal, void *priv,
> -				 char *buf)
> -{
> -	const struct counter_signal_enum_ext *const e = priv;
> -	int err;
> -	size_t index;
> -
> -	if (!e->get)
> -		return -EINVAL;
> -
> -	err = e->get(counter, signal, &index);
> -	if (err)
> -		return err;
> -
> -	if (index >= e->num_items)
> -		return -EINVAL;
> -
> -	return sprintf(buf, "%s\n", e->items[index]);
> -}
> -EXPORT_SYMBOL_GPL(counter_signal_enum_read);
> -
> -ssize_t counter_signal_enum_write(struct counter_device *counter,
> -				  struct counter_signal *signal, void *priv,
> -				  const char *buf, size_t len)
> -{
> -	const struct counter_signal_enum_ext *const e = priv;
> -	ssize_t index;
> -	int err;
> -
> -	if (!e->set)
> -		return -EINVAL;
> -
> -	index = __sysfs_match_string(e->items, e->num_items, buf);
> -	if (index < 0)
> -		return index;
> -
> -	err = e->set(counter, signal, index);
> -	if (err)
> -		return err;
> -
> -	return len;
> -}
> -EXPORT_SYMBOL_GPL(counter_signal_enum_write);
> -
> -ssize_t counter_signal_enum_available_read(struct counter_device *counter,
> -					   struct counter_signal *signal,
> -					   void *priv, char *buf)
> -{
> -	const struct counter_signal_enum_ext *const e = priv;
> -	size_t i;
> -	size_t len = 0;
> -
> -	if (!e->num_items)
> -		return 0;
> -
> -	for (i = 0; i < e->num_items; i++)
> -		len += sprintf(buf + len, "%s\n", e->items[i]);
> -
> -	return len;
> -}
> -EXPORT_SYMBOL_GPL(counter_signal_enum_available_read);
> -
> -ssize_t counter_count_enum_read(struct counter_device *counter,
> -				struct counter_count *count, void *priv,
> -				char *buf)
> -{
> -	const struct counter_count_enum_ext *const e = priv;
> -	int err;
> -	size_t index;
> -
> -	if (!e->get)
> -		return -EINVAL;
> -
> -	err = e->get(counter, count, &index);
> -	if (err)
> -		return err;
> -
> -	if (index >= e->num_items)
> -		return -EINVAL;
> -
> -	return sprintf(buf, "%s\n", e->items[index]);
> -}
> -EXPORT_SYMBOL_GPL(counter_count_enum_read);
> -
> -ssize_t counter_count_enum_write(struct counter_device *counter,
> -				 struct counter_count *count, void *priv,
> -				 const char *buf, size_t len)
> -{
> -	const struct counter_count_enum_ext *const e = priv;
> -	ssize_t index;
> -	int err;
> -
> -	if (!e->set)
> -		return -EINVAL;
> -
> -	index = __sysfs_match_string(e->items, e->num_items, buf);
> -	if (index < 0)
> -		return index;
> -
> -	err = e->set(counter, count, index);
> -	if (err)
> -		return err;
> -
> -	return len;
> -}
> -EXPORT_SYMBOL_GPL(counter_count_enum_write);
> -
> -ssize_t counter_count_enum_available_read(struct counter_device *counter,
> -					  struct counter_count *count,
> -					  void *priv, char *buf)
> -{
> -	const struct counter_count_enum_ext *const e = priv;
> -	size_t i;
> -	size_t len = 0;
> -
> -	if (!e->num_items)
> -		return 0;
> -
> -	for (i = 0; i < e->num_items; i++)
> -		len += sprintf(buf + len, "%s\n", e->items[i]);
> -
> -	return len;
> -}
> -EXPORT_SYMBOL_GPL(counter_count_enum_available_read);
> -
> -ssize_t counter_device_enum_read(struct counter_device *counter, void *priv,
> -				 char *buf)
> -{
> -	const struct counter_device_enum_ext *const e = priv;
> -	int err;
> -	size_t index;
> -
> -	if (!e->get)
> -		return -EINVAL;
> -
> -	err = e->get(counter, &index);
> -	if (err)
> -		return err;
> -
> -	if (index >= e->num_items)
> -		return -EINVAL;
> -
> -	return sprintf(buf, "%s\n", e->items[index]);
> -}
> -EXPORT_SYMBOL_GPL(counter_device_enum_read);
> -
> -ssize_t counter_device_enum_write(struct counter_device *counter, void *priv,
> -				  const char *buf, size_t len)
> -{
> -	const struct counter_device_enum_ext *const e = priv;
> -	ssize_t index;
> -	int err;
> -
> -	if (!e->set)
> -		return -EINVAL;
> -
> -	index = __sysfs_match_string(e->items, e->num_items, buf);
> -	if (index < 0)
> -		return index;
> -
> -	err = e->set(counter, index);
> -	if (err)
> -		return err;
> -
> -	return len;
> -}
> -EXPORT_SYMBOL_GPL(counter_device_enum_write);
> -
> -ssize_t counter_device_enum_available_read(struct counter_device *counter,
> -					   void *priv, char *buf)
> -{
> -	const struct counter_device_enum_ext *const e = priv;
> -	size_t i;
> -	size_t len = 0;
> -
> -	if (!e->num_items)
> -		return 0;
> -
> -	for (i = 0; i < e->num_items; i++)
> -		len += sprintf(buf + len, "%s\n", e->items[i]);
> -
> -	return len;
> -}
> -EXPORT_SYMBOL_GPL(counter_device_enum_available_read);
> -
> -struct counter_attr_parm {
> -	struct counter_device_attr_group *group;
> -	const char *prefix;
> -	const char *name;
> -	ssize_t (*show)(struct device *dev, struct device_attribute *attr,
> -			char *buf);
> -	ssize_t (*store)(struct device *dev, struct device_attribute *attr,
> -			 const char *buf, size_t len);
> -	void *component;
> -};
> -
> -struct counter_device_attr {
> -	struct device_attribute dev_attr;
> -	struct list_head l;
> -	void *component;
> -};
> -
> -static int counter_attribute_create(const struct counter_attr_parm *const parm)
> -{
> -	struct counter_device_attr *counter_attr;
> -	struct device_attribute *dev_attr;
> -	int err;
> -	struct list_head *const attr_list = &parm->group->attr_list;
> -
> -	/* Allocate a Counter device attribute */
> -	counter_attr = kzalloc(sizeof(*counter_attr), GFP_KERNEL);
> -	if (!counter_attr)
> -		return -ENOMEM;
> -	dev_attr = &counter_attr->dev_attr;
> -
> -	sysfs_attr_init(&dev_attr->attr);
> -
> -	/* Configure device attribute */
> -	dev_attr->attr.name = kasprintf(GFP_KERNEL, "%s%s", parm->prefix,
> -					parm->name);
> -	if (!dev_attr->attr.name) {
> -		err = -ENOMEM;
> -		goto err_free_counter_attr;
> -	}
> -	if (parm->show) {
> -		dev_attr->attr.mode |= 0444;
> -		dev_attr->show = parm->show;
> -	}
> -	if (parm->store) {
> -		dev_attr->attr.mode |= 0200;
> -		dev_attr->store = parm->store;
> -	}
> -
> -	/* Store associated Counter component with attribute */
> -	counter_attr->component = parm->component;
> -
> -	/* Keep track of the attribute for later cleanup */
> -	list_add(&counter_attr->l, attr_list);
> -	parm->group->num_attr++;
> -
> -	return 0;
> -
> -err_free_counter_attr:
> -	kfree(counter_attr);
> -	return err;
> -}
> -
> -#define to_counter_attr(_dev_attr) \
> -	container_of(_dev_attr, struct counter_device_attr, dev_attr)
> -
> -struct counter_signal_unit {
> -	struct counter_signal *signal;
> -};
> -
> -static const char *const counter_signal_value_str[] = {
> -	[COUNTER_SIGNAL_LOW] = "low",
> -	[COUNTER_SIGNAL_HIGH] = "high"
> -};
> -
> -static ssize_t counter_signal_show(struct device *dev,
> -				   struct device_attribute *attr, char *buf)
> -{
> -	struct counter_device *const counter = dev_get_drvdata(dev);
> -	const struct counter_device_attr *const devattr = to_counter_attr(attr);
> -	const struct counter_signal_unit *const component = devattr->component;
> -	struct counter_signal *const signal = component->signal;
> -	int err;
> -	enum counter_signal_value val;
> -
> -	err = counter->ops->signal_read(counter, signal, &val);
> -	if (err)
> -		return err;
> -
> -	return sprintf(buf, "%s\n", counter_signal_value_str[val]);
> -}
> -
> -struct counter_name_unit {
> -	const char *name;
> -};
> -
> -static ssize_t counter_device_attr_name_show(struct device *dev,
> -					     struct device_attribute *attr,
> -					     char *buf)
> -{
> -	const struct counter_name_unit *const comp = to_counter_attr(attr)->component;
> -
> -	return sprintf(buf, "%s\n", comp->name);
> -}
> -
> -static int counter_name_attribute_create(
> -	struct counter_device_attr_group *const group,
> -	const char *const name)
> -{
> -	struct counter_name_unit *name_comp;
> -	struct counter_attr_parm parm;
> -	int err;
> -
> -	/* Skip if no name */
> -	if (!name)
> -		return 0;
> -
> -	/* Allocate name attribute component */
> -	name_comp = kmalloc(sizeof(*name_comp), GFP_KERNEL);
> -	if (!name_comp)
> -		return -ENOMEM;
> -	name_comp->name = name;
> -
> -	/* Allocate Signal name attribute */
> -	parm.group = group;
> -	parm.prefix = "";
> -	parm.name = "name";
> -	parm.show = counter_device_attr_name_show;
> -	parm.store = NULL;
> -	parm.component = name_comp;
> -	err = counter_attribute_create(&parm);
> -	if (err)
> -		goto err_free_name_comp;
> -
> -	return 0;
> -
> -err_free_name_comp:
> -	kfree(name_comp);
> -	return err;
> -}
> -
> -struct counter_signal_ext_unit {
> -	struct counter_signal *signal;
> -	const struct counter_signal_ext *ext;
> -};
> -
> -static ssize_t counter_signal_ext_show(struct device *dev,
> -				       struct device_attribute *attr, char *buf)
> -{
> -	const struct counter_device_attr *const devattr = to_counter_attr(attr);
> -	const struct counter_signal_ext_unit *const comp = devattr->component;
> -	const struct counter_signal_ext *const ext = comp->ext;
> -
> -	return ext->read(dev_get_drvdata(dev), comp->signal, ext->priv, buf);
> -}
> -
> -static ssize_t counter_signal_ext_store(struct device *dev,
> -					struct device_attribute *attr,
> -					const char *buf, size_t len)
> -{
> -	const struct counter_device_attr *const devattr = to_counter_attr(attr);
> -	const struct counter_signal_ext_unit *const comp = devattr->component;
> -	const struct counter_signal_ext *const ext = comp->ext;
> -
> -	return ext->write(dev_get_drvdata(dev), comp->signal, ext->priv, buf,
> -		len);
> -}
> -
> -static void counter_device_attr_list_free(struct list_head *attr_list)
> -{
> -	struct counter_device_attr *p, *n;
> -
> -	list_for_each_entry_safe(p, n, attr_list, l) {
> -		/* free attribute name and associated component memory */
> -		kfree(p->dev_attr.attr.name);
> -		kfree(p->component);
> -		list_del(&p->l);
> -		kfree(p);
> -	}
> -}
> -
> -static int counter_signal_ext_register(
> -	struct counter_device_attr_group *const group,
> -	struct counter_signal *const signal)
> -{
> -	const size_t num_ext = signal->num_ext;
> -	size_t i;
> -	const struct counter_signal_ext *ext;
> -	struct counter_signal_ext_unit *signal_ext_comp;
> -	struct counter_attr_parm parm;
> -	int err;
> -
> -	/* Create an attribute for each extension */
> -	for (i = 0 ; i < num_ext; i++) {
> -		ext = signal->ext + i;
> -
> -		/* Allocate signal_ext attribute component */
> -		signal_ext_comp = kmalloc(sizeof(*signal_ext_comp), GFP_KERNEL);
> -		if (!signal_ext_comp) {
> -			err = -ENOMEM;
> -			goto err_free_attr_list;
> -		}
> -		signal_ext_comp->signal = signal;
> -		signal_ext_comp->ext = ext;
> -
> -		/* Allocate a Counter device attribute */
> -		parm.group = group;
> -		parm.prefix = "";
> -		parm.name = ext->name;
> -		parm.show = (ext->read) ? counter_signal_ext_show : NULL;
> -		parm.store = (ext->write) ? counter_signal_ext_store : NULL;
> -		parm.component = signal_ext_comp;
> -		err = counter_attribute_create(&parm);
> -		if (err) {
> -			kfree(signal_ext_comp);
> -			goto err_free_attr_list;
> -		}
> -	}
> -
> -	return 0;
> -
> -err_free_attr_list:
> -	counter_device_attr_list_free(&group->attr_list);
> -	return err;
> -}
> -
> -static int counter_signal_attributes_create(
> -	struct counter_device_attr_group *const group,
> -	const struct counter_device *const counter,
> -	struct counter_signal *const signal)
> -{
> -	struct counter_signal_unit *signal_comp;
> -	struct counter_attr_parm parm;
> -	int err;
> -
> -	/* Allocate Signal attribute component */
> -	signal_comp = kmalloc(sizeof(*signal_comp), GFP_KERNEL);
> -	if (!signal_comp)
> -		return -ENOMEM;
> -	signal_comp->signal = signal;
> -
> -	/* Create main Signal attribute */
> -	parm.group = group;
> -	parm.prefix = "";
> -	parm.name = "signal";
> -	parm.show = (counter->ops->signal_read) ? counter_signal_show : NULL;
> -	parm.store = NULL;
> -	parm.component = signal_comp;
> -	err = counter_attribute_create(&parm);
> -	if (err) {
> -		kfree(signal_comp);
> -		return err;
> -	}
> -
> -	/* Create Signal name attribute */
> -	err = counter_name_attribute_create(group, signal->name);
> -	if (err)
> -		goto err_free_attr_list;
> -
> -	/* Register Signal extension attributes */
> -	err = counter_signal_ext_register(group, signal);
> -	if (err)
> -		goto err_free_attr_list;
> -
> -	return 0;
> -
> -err_free_attr_list:
> -	counter_device_attr_list_free(&group->attr_list);
> -	return err;
> -}
> -
> -static int counter_signals_register(
> -	struct counter_device_attr_group *const groups_list,
> -	const struct counter_device *const counter)
> -{
> -	const size_t num_signals = counter->num_signals;
> -	size_t i;
> -	struct counter_signal *signal;
> -	const char *name;
> -	int err;
> -
> -	/* Register each Signal */
> -	for (i = 0; i < num_signals; i++) {
> -		signal = counter->signals + i;
> -
> -		/* Generate Signal attribute directory name */
> -		name = kasprintf(GFP_KERNEL, "signal%d", signal->id);
> -		if (!name) {
> -			err = -ENOMEM;
> -			goto err_free_attr_groups;
> -		}
> -		groups_list[i].attr_group.name = name;
> -
> -		/* Create all attributes associated with Signal */
> -		err = counter_signal_attributes_create(groups_list + i, counter,
> -						       signal);
> -		if (err)
> -			goto err_free_attr_groups;
> -	}
> -
> -	return 0;
> -
> -err_free_attr_groups:
> -	do {
> -		kfree(groups_list[i].attr_group.name);
> -		counter_device_attr_list_free(&groups_list[i].attr_list);
> -	} while (i--);
> -	return err;
> -}
> -
> -static const char *const counter_synapse_action_str[] = {
> -	[COUNTER_SYNAPSE_ACTION_NONE] = "none",
> -	[COUNTER_SYNAPSE_ACTION_RISING_EDGE] = "rising edge",
> -	[COUNTER_SYNAPSE_ACTION_FALLING_EDGE] = "falling edge",
> -	[COUNTER_SYNAPSE_ACTION_BOTH_EDGES] = "both edges"
> -};
> -
> -struct counter_action_unit {
> -	struct counter_synapse *synapse;
> -	struct counter_count *count;
> -};
> -
> -static ssize_t counter_action_show(struct device *dev,
> -				   struct device_attribute *attr, char *buf)
> -{
> -	const struct counter_device_attr *const devattr = to_counter_attr(attr);
> -	int err;
> -	struct counter_device *const counter = dev_get_drvdata(dev);
> -	const struct counter_action_unit *const component = devattr->component;
> -	struct counter_count *const count = component->count;
> -	struct counter_synapse *const synapse = component->synapse;
> -	size_t action_index;
> -	enum counter_synapse_action action;
> -
> -	err = counter->ops->action_get(counter, count, synapse, &action_index);
> -	if (err)
> -		return err;
> -
> -	synapse->action = action_index;
> -
> -	action = synapse->actions_list[action_index];
> -	return sprintf(buf, "%s\n", counter_synapse_action_str[action]);
> -}
> -
> -static ssize_t counter_action_store(struct device *dev,
> -				    struct device_attribute *attr,
> -				    const char *buf, size_t len)
> -{
> -	const struct counter_device_attr *const devattr = to_counter_attr(attr);
> -	const struct counter_action_unit *const component = devattr->component;
> -	struct counter_synapse *const synapse = component->synapse;
> -	size_t action_index;
> -	const size_t num_actions = synapse->num_actions;
> -	enum counter_synapse_action action;
> -	int err;
> -	struct counter_device *const counter = dev_get_drvdata(dev);
> -	struct counter_count *const count = component->count;
> -
> -	/* Find requested action mode */
> -	for (action_index = 0; action_index < num_actions; action_index++) {
> -		action = synapse->actions_list[action_index];
> -		if (sysfs_streq(buf, counter_synapse_action_str[action]))
> -			break;
> -	}
> -	/* If requested action mode not found */
> -	if (action_index >= num_actions)
> -		return -EINVAL;
> -
> -	err = counter->ops->action_set(counter, count, synapse, action_index);
> -	if (err)
> -		return err;
> -
> -	synapse->action = action_index;
> -
> -	return len;
> -}
> -
> -struct counter_action_avail_unit {
> -	const enum counter_synapse_action *actions_list;
> -	size_t num_actions;
> -};
> -
> -static ssize_t counter_synapse_action_available_show(struct device *dev,
> -	struct device_attribute *attr, char *buf)
> -{
> -	const struct counter_device_attr *const devattr = to_counter_attr(attr);
> -	const struct counter_action_avail_unit *const component = devattr->component;
> -	size_t i;
> -	enum counter_synapse_action action;
> -	ssize_t len = 0;
> -
> -	for (i = 0; i < component->num_actions; i++) {
> -		action = component->actions_list[i];
> -		len += sprintf(buf + len, "%s\n",
> -			       counter_synapse_action_str[action]);
> -	}
> -
> -	return len;
> -}
> -
> -static int counter_synapses_register(
> -	struct counter_device_attr_group *const group,
> -	const struct counter_device *const counter,
> -	struct counter_count *const count, const char *const count_attr_name)
> -{
> -	size_t i;
> -	struct counter_synapse *synapse;
> -	const char *prefix;
> -	struct counter_action_unit *action_comp;
> -	struct counter_attr_parm parm;
> -	int err;
> -	struct counter_action_avail_unit *avail_comp;
> -
> -	/* Register each Synapse */
> -	for (i = 0; i < count->num_synapses; i++) {
> -		synapse = count->synapses + i;
> -
> -		/* Generate attribute prefix */
> -		prefix = kasprintf(GFP_KERNEL, "signal%d_",
> -				   synapse->signal->id);
> -		if (!prefix) {
> -			err = -ENOMEM;
> -			goto err_free_attr_list;
> -		}
> -
> -		/* Allocate action attribute component */
> -		action_comp = kmalloc(sizeof(*action_comp), GFP_KERNEL);
> -		if (!action_comp) {
> -			err = -ENOMEM;
> -			goto err_free_prefix;
> -		}
> -		action_comp->synapse = synapse;
> -		action_comp->count = count;
> -
> -		/* Create action attribute */
> -		parm.group = group;
> -		parm.prefix = prefix;
> -		parm.name = "action";
> -		parm.show = (counter->ops->action_get) ? counter_action_show : NULL;
> -		parm.store = (counter->ops->action_set) ? counter_action_store : NULL;
> -		parm.component = action_comp;
> -		err = counter_attribute_create(&parm);
> -		if (err) {
> -			kfree(action_comp);
> -			goto err_free_prefix;
> -		}
> -
> -		/* Allocate action available attribute component */
> -		avail_comp = kmalloc(sizeof(*avail_comp), GFP_KERNEL);
> -		if (!avail_comp) {
> -			err = -ENOMEM;
> -			goto err_free_prefix;
> -		}
> -		avail_comp->actions_list = synapse->actions_list;
> -		avail_comp->num_actions = synapse->num_actions;
> -
> -		/* Create action_available attribute */
> -		parm.group = group;
> -		parm.prefix = prefix;
> -		parm.name = "action_available";
> -		parm.show = counter_synapse_action_available_show;
> -		parm.store = NULL;
> -		parm.component = avail_comp;
> -		err = counter_attribute_create(&parm);
> -		if (err) {
> -			kfree(avail_comp);
> -			goto err_free_prefix;
> -		}
> -
> -		kfree(prefix);
> -	}
> -
> -	return 0;
> -
> -err_free_prefix:
> -	kfree(prefix);
> -err_free_attr_list:
> -	counter_device_attr_list_free(&group->attr_list);
> -	return err;
> -}
> -
> -struct counter_count_unit {
> -	struct counter_count *count;
> -};
> -
> -static ssize_t counter_count_show(struct device *dev,
> -				  struct device_attribute *attr,
> -				  char *buf)
> -{
> -	struct counter_device *const counter = dev_get_drvdata(dev);
> -	const struct counter_device_attr *const devattr = to_counter_attr(attr);
> -	const struct counter_count_unit *const component = devattr->component;
> -	struct counter_count *const count = component->count;
> -	int err;
> -	unsigned long val;
> -
> -	err = counter->ops->count_read(counter, count, &val);
> -	if (err)
> -		return err;
> -
> -	return sprintf(buf, "%lu\n", val);
> -}
> -
> -static ssize_t counter_count_store(struct device *dev,
> -				   struct device_attribute *attr,
> -				   const char *buf, size_t len)
> -{
> -	struct counter_device *const counter = dev_get_drvdata(dev);
> -	const struct counter_device_attr *const devattr = to_counter_attr(attr);
> -	const struct counter_count_unit *const component = devattr->component;
> -	struct counter_count *const count = component->count;
> -	int err;
> -	unsigned long val;
> -
> -	err = kstrtoul(buf, 0, &val);
> -	if (err)
> -		return err;
> -
> -	err = counter->ops->count_write(counter, count, val);
> -	if (err)
> -		return err;
> -
> -	return len;
> -}
> -
> -static const char *const counter_count_function_str[] = {
> -	[COUNTER_COUNT_FUNCTION_INCREASE] = "increase",
> -	[COUNTER_COUNT_FUNCTION_DECREASE] = "decrease",
> -	[COUNTER_COUNT_FUNCTION_PULSE_DIRECTION] = "pulse-direction",
> -	[COUNTER_COUNT_FUNCTION_QUADRATURE_X1_A] = "quadrature x1 a",
> -	[COUNTER_COUNT_FUNCTION_QUADRATURE_X1_B] = "quadrature x1 b",
> -	[COUNTER_COUNT_FUNCTION_QUADRATURE_X2_A] = "quadrature x2 a",
> -	[COUNTER_COUNT_FUNCTION_QUADRATURE_X2_B] = "quadrature x2 b",
> -	[COUNTER_COUNT_FUNCTION_QUADRATURE_X4] = "quadrature x4"
> -};
> -
> -static ssize_t counter_function_show(struct device *dev,
> -				     struct device_attribute *attr, char *buf)
> -{
> -	int err;
> -	struct counter_device *const counter = dev_get_drvdata(dev);
> -	const struct counter_device_attr *const devattr = to_counter_attr(attr);
> -	const struct counter_count_unit *const component = devattr->component;
> -	struct counter_count *const count = component->count;
> -	size_t func_index;
> -	enum counter_count_function function;
> -
> -	err = counter->ops->function_get(counter, count, &func_index);
> -	if (err)
> -		return err;
> -
> -	count->function = func_index;
> -
> -	function = count->functions_list[func_index];
> -	return sprintf(buf, "%s\n", counter_count_function_str[function]);
> -}
> -
> -static ssize_t counter_function_store(struct device *dev,
> -				      struct device_attribute *attr,
> -				      const char *buf, size_t len)
> -{
> -	const struct counter_device_attr *const devattr = to_counter_attr(attr);
> -	const struct counter_count_unit *const component = devattr->component;
> -	struct counter_count *const count = component->count;
> -	const size_t num_functions = count->num_functions;
> -	size_t func_index;
> -	enum counter_count_function function;
> -	int err;
> -	struct counter_device *const counter = dev_get_drvdata(dev);
> -
> -	/* Find requested Count function mode */
> -	for (func_index = 0; func_index < num_functions; func_index++) {
> -		function = count->functions_list[func_index];
> -		if (sysfs_streq(buf, counter_count_function_str[function]))
> -			break;
> -	}
> -	/* Return error if requested Count function mode not found */
> -	if (func_index >= num_functions)
> -		return -EINVAL;
> -
> -	err = counter->ops->function_set(counter, count, func_index);
> -	if (err)
> -		return err;
> -
> -	count->function = func_index;
> -
> -	return len;
> -}
> -
> -struct counter_count_ext_unit {
> -	struct counter_count *count;
> -	const struct counter_count_ext *ext;
> -};
> -
> -static ssize_t counter_count_ext_show(struct device *dev,
> -				      struct device_attribute *attr, char *buf)
> -{
> -	const struct counter_device_attr *const devattr = to_counter_attr(attr);
> -	const struct counter_count_ext_unit *const comp = devattr->component;
> -	const struct counter_count_ext *const ext = comp->ext;
> -
> -	return ext->read(dev_get_drvdata(dev), comp->count, ext->priv, buf);
> -}
> -
> -static ssize_t counter_count_ext_store(struct device *dev,
> -				       struct device_attribute *attr,
> -				       const char *buf, size_t len)
> -{
> -	const struct counter_device_attr *const devattr = to_counter_attr(attr);
> -	const struct counter_count_ext_unit *const comp = devattr->component;
> -	const struct counter_count_ext *const ext = comp->ext;
> -
> -	return ext->write(dev_get_drvdata(dev), comp->count, ext->priv, buf,
> -		len);
> -}
> -
> -static int counter_count_ext_register(
> -	struct counter_device_attr_group *const group,
> -	struct counter_count *const count)
> -{
> -	size_t i;
> -	const struct counter_count_ext *ext;
> -	struct counter_count_ext_unit *count_ext_comp;
> -	struct counter_attr_parm parm;
> -	int err;
> -
> -	/* Create an attribute for each extension */
> -	for (i = 0 ; i < count->num_ext; i++) {
> -		ext = count->ext + i;
> -
> -		/* Allocate count_ext attribute component */
> -		count_ext_comp = kmalloc(sizeof(*count_ext_comp), GFP_KERNEL);
> -		if (!count_ext_comp) {
> -			err = -ENOMEM;
> -			goto err_free_attr_list;
> -		}
> -		count_ext_comp->count = count;
> -		count_ext_comp->ext = ext;
> -
> -		/* Allocate count_ext attribute */
> -		parm.group = group;
> -		parm.prefix = "";
> -		parm.name = ext->name;
> -		parm.show = (ext->read) ? counter_count_ext_show : NULL;
> -		parm.store = (ext->write) ? counter_count_ext_store : NULL;
> -		parm.component = count_ext_comp;
> -		err = counter_attribute_create(&parm);
> -		if (err) {
> -			kfree(count_ext_comp);
> -			goto err_free_attr_list;
> -		}
> -	}
> -
> -	return 0;
> -
> -err_free_attr_list:
> -	counter_device_attr_list_free(&group->attr_list);
> -	return err;
> -}
> -
> -struct counter_func_avail_unit {
> -	const enum counter_count_function *functions_list;
> -	size_t num_functions;
> -};
> -
> -static ssize_t counter_count_function_available_show(struct device *dev,
> -	struct device_attribute *attr, char *buf)
> -{
> -	const struct counter_device_attr *const devattr = to_counter_attr(attr);
> -	const struct counter_func_avail_unit *const component = devattr->component;
> -	const enum counter_count_function *const func_list = component->functions_list;
> -	const size_t num_functions = component->num_functions;
> -	size_t i;
> -	enum counter_count_function function;
> -	ssize_t len = 0;
> -
> -	for (i = 0; i < num_functions; i++) {
> -		function = func_list[i];
> -		len += sprintf(buf + len, "%s\n",
> -			       counter_count_function_str[function]);
> -	}
> -
> -	return len;
> -}
> -
> -static int counter_count_attributes_create(
> -	struct counter_device_attr_group *const group,
> -	const struct counter_device *const counter,
> -	struct counter_count *const count)
> -{
> -	struct counter_count_unit *count_comp;
> -	struct counter_attr_parm parm;
> -	int err;
> -	struct counter_count_unit *func_comp;
> -	struct counter_func_avail_unit *avail_comp;
> -
> -	/* Allocate count attribute component */
> -	count_comp = kmalloc(sizeof(*count_comp), GFP_KERNEL);
> -	if (!count_comp)
> -		return -ENOMEM;
> -	count_comp->count = count;
> -
> -	/* Create main Count attribute */
> -	parm.group = group;
> -	parm.prefix = "";
> -	parm.name = "count";
> -	parm.show = (counter->ops->count_read) ? counter_count_show : NULL;
> -	parm.store = (counter->ops->count_write) ? counter_count_store : NULL;
> -	parm.component = count_comp;
> -	err = counter_attribute_create(&parm);
> -	if (err) {
> -		kfree(count_comp);
> -		return err;
> -	}
> -
> -	/* Allocate function attribute component */
> -	func_comp = kmalloc(sizeof(*func_comp), GFP_KERNEL);
> -	if (!func_comp) {
> -		err = -ENOMEM;
> -		goto err_free_attr_list;
> -	}
> -	func_comp->count = count;
> -
> -	/* Create Count function attribute */
> -	parm.group = group;
> -	parm.prefix = "";
> -	parm.name = "function";
> -	parm.show = (counter->ops->function_get) ? counter_function_show : NULL;
> -	parm.store = (counter->ops->function_set) ? counter_function_store : NULL;
> -	parm.component = func_comp;
> -	err = counter_attribute_create(&parm);
> -	if (err) {
> -		kfree(func_comp);
> -		goto err_free_attr_list;
> -	}
> -
> -	/* Allocate function available attribute component */
> -	avail_comp = kmalloc(sizeof(*avail_comp), GFP_KERNEL);
> -	if (!avail_comp) {
> -		err = -ENOMEM;
> -		goto err_free_attr_list;
> -	}
> -	avail_comp->functions_list = count->functions_list;
> -	avail_comp->num_functions = count->num_functions;
> -
> -	/* Create Count function_available attribute */
> -	parm.group = group;
> -	parm.prefix = "";
> -	parm.name = "function_available";
> -	parm.show = counter_count_function_available_show;
> -	parm.store = NULL;
> -	parm.component = avail_comp;
> -	err = counter_attribute_create(&parm);
> -	if (err) {
> -		kfree(avail_comp);
> -		goto err_free_attr_list;
> -	}
> -
> -	/* Create Count name attribute */
> -	err = counter_name_attribute_create(group, count->name);
> -	if (err)
> -		goto err_free_attr_list;
> -
> -	/* Register Count extension attributes */
> -	err = counter_count_ext_register(group, count);
> -	if (err)
> -		goto err_free_attr_list;
> -
> -	return 0;
> -
> -err_free_attr_list:
> -	counter_device_attr_list_free(&group->attr_list);
> -	return err;
> -}
> -
> -static int counter_counts_register(
> -	struct counter_device_attr_group *const groups_list,
> -	const struct counter_device *const counter)
> -{
> -	size_t i;
> -	struct counter_count *count;
> -	const char *name;
> -	int err;
> -
> -	/* Register each Count */
> -	for (i = 0; i < counter->num_counts; i++) {
> -		count = counter->counts + i;
> -
> -		/* Generate Count attribute directory name */
> -		name = kasprintf(GFP_KERNEL, "count%d", count->id);
> -		if (!name) {
> -			err = -ENOMEM;
> -			goto err_free_attr_groups;
> -		}
> -		groups_list[i].attr_group.name = name;
> -
> -		/* Register the Synapses associated with each Count */
> -		err = counter_synapses_register(groups_list + i, counter, count,
> -						name);
> -		if (err)
> -			goto err_free_attr_groups;
> -
> -		/* Create all attributes associated with Count */
> -		err = counter_count_attributes_create(groups_list + i, counter,
> -						      count);
> -		if (err)
> -			goto err_free_attr_groups;
> -	}
> -
> -	return 0;
> -
> -err_free_attr_groups:
> -	do {
> -		kfree(groups_list[i].attr_group.name);
> -		counter_device_attr_list_free(&groups_list[i].attr_list);
> -	} while (i--);
> -	return err;
> -}
> -
> -struct counter_size_unit {
> -	size_t size;
> -};
> -
> -static ssize_t counter_device_attr_size_show(struct device *dev,
> -					     struct device_attribute *attr,
> -					     char *buf)
> -{
> -	const struct counter_size_unit *const comp = to_counter_attr(attr)->component;
> -
> -	return sprintf(buf, "%zu\n", comp->size);
> -}
> -
> -static int counter_size_attribute_create(
> -	struct counter_device_attr_group *const group,
> -	const size_t size, const char *const name)
> -{
> -	struct counter_size_unit *size_comp;
> -	struct counter_attr_parm parm;
> -	int err;
> -
> -	/* Allocate size attribute component */
> -	size_comp = kmalloc(sizeof(*size_comp), GFP_KERNEL);
> -	if (!size_comp)
> -		return -ENOMEM;
> -	size_comp->size = size;
> -
> -	parm.group = group;
> -	parm.prefix = "";
> -	parm.name = name;
> -	parm.show = counter_device_attr_size_show;
> -	parm.store = NULL;
> -	parm.component = size_comp;
> -	err = counter_attribute_create(&parm);
> -	if (err)
> -		goto err_free_size_comp;
> -
> -	return 0;
> -
> -err_free_size_comp:
> -	kfree(size_comp);
> -	return err;
> -}
> -
> -struct counter_ext_unit {
> -	const struct counter_device_ext *ext;
> -};
> -
> -static ssize_t counter_device_ext_show(struct device *dev,
> -				       struct device_attribute *attr, char *buf)
> -{
> -	const struct counter_device_attr *const devattr = to_counter_attr(attr);
> -	const struct counter_ext_unit *const component = devattr->component;
> -	const struct counter_device_ext *const ext = component->ext;
> -
> -	return ext->read(dev_get_drvdata(dev), ext->priv, buf);
> -}
> -
> -static ssize_t counter_device_ext_store(struct device *dev,
> -					struct device_attribute *attr,
> -					const char *buf, size_t len)
> -{
> -	const struct counter_device_attr *const devattr = to_counter_attr(attr);
> -	const struct counter_ext_unit *const component = devattr->component;
> -	const struct counter_device_ext *const ext = component->ext;
> -
> -	return ext->write(dev_get_drvdata(dev), ext->priv, buf, len);
> -}
> -
> -static int counter_device_ext_register(
> -	struct counter_device_attr_group *const group,
> -	struct counter_device *const counter)
> -{
> -	size_t i;
> -	struct counter_ext_unit *ext_comp;
> -	struct counter_attr_parm parm;
> -	int err;
> -
> -	/* Create an attribute for each extension */
> -	for (i = 0 ; i < counter->num_ext; i++) {
> -		/* Allocate extension attribute component */
> -		ext_comp = kmalloc(sizeof(*ext_comp), GFP_KERNEL);
> -		if (!ext_comp) {
> -			err = -ENOMEM;
> -			goto err_free_attr_list;
> -		}
> -
> -		ext_comp->ext = counter->ext + i;
> -
> -		/* Allocate extension attribute */
> -		parm.group = group;
> -		parm.prefix = "";
> -		parm.name = counter->ext[i].name;
> -		parm.show = (counter->ext[i].read) ? counter_device_ext_show : NULL;
> -		parm.store = (counter->ext[i].write) ? counter_device_ext_store : NULL;
> -		parm.component = ext_comp;
> -		err = counter_attribute_create(&parm);
> -		if (err) {
> -			kfree(ext_comp);
> -			goto err_free_attr_list;
> -		}
> -	}
> -
> -	return 0;
> -
> -err_free_attr_list:
> -	counter_device_attr_list_free(&group->attr_list);
> -	return err;
> -}
> -
> -static int counter_global_attr_register(
> -	struct counter_device_attr_group *const group,
> -	struct counter_device *const counter)
> -{
> -	int err;
> -
> -	/* Create name attribute */
> -	err = counter_name_attribute_create(group, counter->name);
> -	if (err)
> -		return err;
> -
> -	/* Create num_counts attribute */
> -	err = counter_size_attribute_create(group, counter->num_counts,
> -					    "num_counts");
> -	if (err)
> -		goto err_free_attr_list;
> -
> -	/* Create num_signals attribute */
> -	err = counter_size_attribute_create(group, counter->num_signals,
> -					    "num_signals");
> -	if (err)
> -		goto err_free_attr_list;
> -
> -	/* Register Counter device extension attributes */
> -	err = counter_device_ext_register(group, counter);
> -	if (err)
> -		goto err_free_attr_list;
> -
> -	return 0;
> -
> -err_free_attr_list:
> -	counter_device_attr_list_free(&group->attr_list);
> -	return err;
> -}
> -
> -static void counter_device_groups_list_free(
> -	struct counter_device_attr_group *const groups_list,
> -	const size_t num_groups)
> -{
> -	struct counter_device_attr_group *group;
> -	size_t i;
> -
> -	/* loop through all attribute groups (signals, counts, global, etc.) */
> -	for (i = 0; i < num_groups; i++) {
> -		group = groups_list + i;
> -
> -		/* free all attribute group and associated attributes memory */
> -		kfree(group->attr_group.name);
> -		kfree(group->attr_group.attrs);
> -		counter_device_attr_list_free(&group->attr_list);
> -	}
> -
> -	kfree(groups_list);
> -}
> -
> -static int counter_device_groups_list_prepare(
> -	struct counter_device *const counter)
> -{
> -	const size_t total_num_groups =
> -		counter->num_signals + counter->num_counts + 1;
> -	struct counter_device_attr_group *groups_list;
> -	size_t i;
> -	int err;
> -	size_t num_groups = 0;
> -
> -	/* Allocate space for attribute groups (signals, counts, and ext) */
> -	groups_list = kcalloc(total_num_groups, sizeof(*groups_list),
> -			      GFP_KERNEL);
> -	if (!groups_list)
> -		return -ENOMEM;
> -
> -	/* Initialize attribute lists */
> -	for (i = 0; i < total_num_groups; i++)
> -		INIT_LIST_HEAD(&groups_list[i].attr_list);
> -
> -	/* Register Signals */
> -	err = counter_signals_register(groups_list, counter);
> -	if (err)
> -		goto err_free_groups_list;
> -	num_groups += counter->num_signals;
> -
> -	/* Register Counts and respective Synapses */
> -	err = counter_counts_register(groups_list + num_groups, counter);
> -	if (err)
> -		goto err_free_groups_list;
> -	num_groups += counter->num_counts;
> -
> -	/* Register Counter global attributes */
> -	err = counter_global_attr_register(groups_list + num_groups, counter);
> -	if (err)
> -		goto err_free_groups_list;
> -	num_groups++;
> -
> -	/* Store groups_list in device_state */
> -	counter->device_state->groups_list = groups_list;
> -	counter->device_state->num_groups = num_groups;
> -
> -	return 0;
> -
> -err_free_groups_list:
> -	counter_device_groups_list_free(groups_list, num_groups);
> -	return err;
> -}
> -
> -static int counter_device_groups_prepare(
> -	struct counter_device_state *const device_state)
> -{
> -	size_t i, j;
> -	struct counter_device_attr_group *group;
> -	int err;
> -	struct counter_device_attr *p;
> -
> -	/* Allocate attribute groups for association with device */
> -	device_state->groups = kcalloc(device_state->num_groups + 1,
> -				       sizeof(*device_state->groups),
> -				       GFP_KERNEL);
> -	if (!device_state->groups)
> -		return -ENOMEM;
> -
> -	/* Prepare each group of attributes for association */
> -	for (i = 0; i < device_state->num_groups; i++) {
> -		group = device_state->groups_list + i;
> -
> -		/* Allocate space for attribute pointers in attribute group */
> -		group->attr_group.attrs = kcalloc(group->num_attr + 1,
> -			sizeof(*group->attr_group.attrs), GFP_KERNEL);
> -		if (!group->attr_group.attrs) {
> -			err = -ENOMEM;
> -			goto err_free_groups;
> -		}
> -
> -		/* Add attribute pointers to attribute group */
> -		j = 0;
> -		list_for_each_entry(p, &group->attr_list, l)
> -			group->attr_group.attrs[j++] = &p->dev_attr.attr;
> -
> -		/* Group attributes in attribute group */
> -		device_state->groups[i] = &group->attr_group;
> -	}
> -	/* Associate attributes with device */
> -	device_state->dev.groups = device_state->groups;
> -
> -	return 0;
> -
> -err_free_groups:
> -	do {
> -		group = device_state->groups_list + i;
> -		kfree(group->attr_group.attrs);
> -		group->attr_group.attrs = NULL;
> -	} while (i--);
> -	kfree(device_state->groups);
> -	return err;
> -}
> -
> -/* Provides a unique ID for each counter device */
> -static DEFINE_IDA(counter_ida);
> -
> -static void counter_device_release(struct device *dev)
> -{
> -	struct counter_device *const counter = dev_get_drvdata(dev);
> -	struct counter_device_state *const device_state = counter->device_state;
> -
> -	kfree(device_state->groups);
> -	counter_device_groups_list_free(device_state->groups_list,
> -					device_state->num_groups);
> -	ida_simple_remove(&counter_ida, device_state->id);
> -	kfree(device_state);
> -}
> -
> -static struct device_type counter_device_type = {
> -	.name = "counter_device",
> -	.release = counter_device_release
> -};
> -
> -static struct bus_type counter_bus_type = {
> -	.name = "counter"
> -};
> -
> -/**
> - * counter_register - register Counter to the system
> - * @counter:	pointer to Counter to register
> - *
> - * This function registers a Counter to the system. A sysfs "counter" directory
> - * will be created and populated with sysfs attributes correlating with the
> - * Counter Signals, Synapses, and Counts respectively.
> - */
> -int counter_register(struct counter_device *const counter)
> -{
> -	struct counter_device_state *device_state;
> -	int err;
> -
> -	/* Allocate internal state container for Counter device */
> -	device_state = kzalloc(sizeof(*device_state), GFP_KERNEL);
> -	if (!device_state)
> -		return -ENOMEM;
> -	counter->device_state = device_state;
> -
> -	/* Acquire unique ID */
> -	device_state->id = ida_simple_get(&counter_ida, 0, 0, GFP_KERNEL);
> -	if (device_state->id < 0) {
> -		err = device_state->id;
> -		goto err_free_device_state;
> -	}
> -
> -	/* Configure device structure for Counter */
> -	device_state->dev.type = &counter_device_type;
> -	device_state->dev.bus = &counter_bus_type;
> -	if (counter->parent) {
> -		device_state->dev.parent = counter->parent;
> -		device_state->dev.of_node = counter->parent->of_node;
> -	}
> -	dev_set_name(&device_state->dev, "counter%d", device_state->id);
> -	device_initialize(&device_state->dev);
> -	dev_set_drvdata(&device_state->dev, counter);
> -
> -	/* Prepare device attributes */
> -	err = counter_device_groups_list_prepare(counter);
> -	if (err)
> -		goto err_free_id;
> -
> -	/* Organize device attributes to groups and match to device */
> -	err = counter_device_groups_prepare(device_state);
> -	if (err)
> -		goto err_free_groups_list;
> -
> -	/* Add device to system */
> -	err = device_add(&device_state->dev);
> -	if (err)
> -		goto err_free_groups;
> -
> -	return 0;
> -
> -err_free_groups:
> -	kfree(device_state->groups);
> -err_free_groups_list:
> -	counter_device_groups_list_free(device_state->groups_list,
> -					device_state->num_groups);
> -err_free_id:
> -	ida_simple_remove(&counter_ida, device_state->id);
> -err_free_device_state:
> -	kfree(device_state);
> -	return err;
> -}
> -EXPORT_SYMBOL_GPL(counter_register);
> -
> -/**
> - * counter_unregister - unregister Counter from the system
> - * @counter:	pointer to Counter to unregister
> - *
> - * The Counter is unregistered from the system; all allocated memory is freed.
> - */
> -void counter_unregister(struct counter_device *const counter)
> -{
> -	if (counter)
> -		device_del(&counter->device_state->dev);
> -}
> -EXPORT_SYMBOL_GPL(counter_unregister);
> -
> -static void devm_counter_unreg(struct device *dev, void *res)
> -{
> -	counter_unregister(*(struct counter_device **)res);
> -}
> -
> -/**
> - * devm_counter_register - Resource-managed counter_register
> - * @dev:	device to allocate counter_device for
> - * @counter:	pointer to Counter to register
> - *
> - * Managed counter_register. The Counter registered with this function is
> - * automatically unregistered on driver detach. This function calls
> - * counter_register internally. Refer to that function for more information.
> - *
> - * If an Counter registered with this function needs to be unregistered
> - * separately, devm_counter_unregister must be used.
> - *
> - * RETURNS:
> - * 0 on success, negative error number on failure.
> - */
> -int devm_counter_register(struct device *dev,
> -			  struct counter_device *const counter)
> -{
> -	struct counter_device **ptr;
> -	int ret;
> -
> -	ptr = devres_alloc(devm_counter_unreg, sizeof(*ptr), GFP_KERNEL);
> -	if (!ptr)
> -		return -ENOMEM;
> -
> -	ret = counter_register(counter);
> -	if (!ret) {
> -		*ptr = counter;
> -		devres_add(dev, ptr);
> -	} else {
> -		devres_free(ptr);
> -	}
> -
> -	return ret;
> -}
> -EXPORT_SYMBOL_GPL(devm_counter_register);
> -
> -static int devm_counter_match(struct device *dev, void *res, void *data)
> -{
> -	struct counter_device **r = res;
> -
> -	if (!r || !*r) {
> -		WARN_ON(!r || !*r);
> -		return 0;
> -	}
> -
> -	return *r == data;
> -}
> -
> -/**
> - * devm_counter_unregister - Resource-managed counter_unregister
> - * @dev:	device this counter_device belongs to
> - * @counter:	pointer to Counter associated with the device
> - *
> - * Unregister Counter registered with devm_counter_register.
> - */
> -void devm_counter_unregister(struct device *dev,
> -			     struct counter_device *const counter)
> -{
> -	int rc;
> -
> -	rc = devres_release(dev, devm_counter_unreg, devm_counter_match,
> -			    counter);
> -	WARN_ON(rc);
> -}
> -EXPORT_SYMBOL_GPL(devm_counter_unregister);
> -
> -static int __init counter_init(void)
> -{
> -	return bus_register(&counter_bus_type);
> -}
> -
> -static void __exit counter_exit(void)
> -{
> -	bus_unregister(&counter_bus_type);
> -}
> -
> -subsys_initcall(counter_init);
> -module_exit(counter_exit);
> -
> -MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@...il.com>");
> -MODULE_DESCRIPTION("Generic Counter interface");
> -MODULE_LICENSE("GPL v2");
> diff --git a/drivers/counter/ftm-quaddec.c b/drivers/counter/ftm-quaddec.c
> index c2b3fdfd8b77..450353f495a2 100644
> --- a/drivers/counter/ftm-quaddec.c
> +++ b/drivers/counter/ftm-quaddec.c
> @@ -151,29 +151,19 @@ static const char * const ftm_quaddec_prescaler[] = {
>  	"1", "2", "4", "8", "16", "32", "64", "128"
>  };
>  
> -static struct counter_count_enum_ext ftm_quaddec_prescaler_enum = {
> -	.items = ftm_quaddec_prescaler,
> -	.num_items = ARRAY_SIZE(ftm_quaddec_prescaler),
> -	.get = ftm_quaddec_get_prescaler,
> -	.set = ftm_quaddec_set_prescaler
> -};
> -
> -enum ftm_quaddec_synapse_action {
> -	FTM_QUADDEC_SYNAPSE_ACTION_BOTH_EDGES,
> -};
> +static DEFINE_COUNTER_ENUM(ftm_quaddec_prescaler_enum, ftm_quaddec_prescaler);
>  
> -static enum counter_synapse_action ftm_quaddec_synapse_actions[] = {
> -	[FTM_QUADDEC_SYNAPSE_ACTION_BOTH_EDGES] =
> +static const enum counter_synapse_action ftm_quaddec_synapse_actions[] = {
>  	COUNTER_SYNAPSE_ACTION_BOTH_EDGES
>  };
>  
>  enum ftm_quaddec_count_function {
> -	FTM_QUADDEC_COUNT_ENCODER_MODE_1,
> +	FTM_QUADDEC_COUNT_ENCODER_MODE_1 =
> +	COUNTER_COUNT_FUNCTION_QUADRATURE_X4
>  };
>  
>  static const enum counter_count_function ftm_quaddec_count_functions[] = {
> -	[FTM_QUADDEC_COUNT_ENCODER_MODE_1] =
> -	COUNTER_COUNT_FUNCTION_QUADRATURE_X4
> +	FTM_QUADDEC_COUNT_ENCODER_MODE_1
>  };
>  
>  static int ftm_quaddec_count_read(struct counter_device *counter,
> @@ -208,7 +198,7 @@ static int ftm_quaddec_count_write(struct counter_device *counter,
>  
>  static int ftm_quaddec_count_function_get(struct counter_device *counter,
>  					  struct counter_count *count,
> -					  size_t *function)
> +					  enum counter_count_function *function)
>  {
>  	*function = FTM_QUADDEC_COUNT_ENCODER_MODE_1;
>  
> @@ -218,20 +208,13 @@ static int ftm_quaddec_count_function_get(struct counter_device *counter,
>  static int ftm_quaddec_action_get(struct counter_device *counter,
>  				  struct counter_count *count,
>  				  struct counter_synapse *synapse,
> -				  size_t *action)
> +				  enum counter_synapse_action *action)
>  {
> -	*action = FTM_QUADDEC_SYNAPSE_ACTION_BOTH_EDGES;
> +	*action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES;
>  
>  	return 0;
>  }
>  
> -static const struct counter_ops ftm_quaddec_cnt_ops = {
> -	.count_read = ftm_quaddec_count_read,
> -	.count_write = ftm_quaddec_count_write,
> -	.function_get = ftm_quaddec_count_function_get,
> -	.action_get = ftm_quaddec_action_get,
> -};
> -
>  static struct counter_signal ftm_quaddec_signals[] = {
>  	{
>  		.id = 0,
> @@ -256,9 +239,11 @@ static struct counter_synapse ftm_quaddec_count_synapses[] = {
>  	}
>  };
>  
> -static const struct counter_count_ext ftm_quaddec_count_ext[] = {
> -	COUNTER_COUNT_ENUM("prescaler", &ftm_quaddec_prescaler_enum),
> -	COUNTER_COUNT_ENUM_AVAILABLE("prescaler", &ftm_quaddec_prescaler_enum),
> +static struct counter_data ftm_quaddec_count_ext[] = {
> +	COUNTER_DATA_ENUM_AND_AVAILABLE("prescaler",
> +					ftm_quaddec_get_prescaler,
> +					ftm_quaddec_set_prescaler,
> +					ftm_quaddec_prescaler_enum),
>  };
>  
>  static struct counter_count ftm_quaddec_counts = {
> @@ -302,7 +287,10 @@ static int ftm_quaddec_probe(struct platform_device *pdev)
>  	}
>  	ftm->counter.name = dev_name(&pdev->dev);
>  	ftm->counter.parent = &pdev->dev;
> -	ftm->counter.ops = &ftm_quaddec_cnt_ops;
> +	ftm->counter.count_read = ftm_quaddec_count_read;
> +	ftm->counter.count_write = ftm_quaddec_count_write;
> +	ftm->counter.function_read = ftm_quaddec_count_function_get;
> +	ftm->counter.action_read = ftm_quaddec_action_get;
>  	ftm->counter.counts = &ftm_quaddec_counts;
>  	ftm->counter.num_counts = 1;
>  	ftm->counter.signals = ftm_quaddec_signals;
> diff --git a/drivers/counter/stm32-lptimer-cnt.c b/drivers/counter/stm32-lptimer-cnt.c
> index 8e276eb655f5..53ca88533831 100644
> --- a/drivers/counter/stm32-lptimer-cnt.c
> +++ b/drivers/counter/stm32-lptimer-cnt.c
> @@ -352,30 +352,44 @@ static const struct iio_chan_spec stm32_lptim_cnt_channels = {
>   * @STM32_LPTIM_ENCODER_BOTH_EDGE: count on both edges (IN1 & IN2 quadrature)
>   */
>  enum stm32_lptim_cnt_function {
> -	STM32_LPTIM_COUNTER_INCREASE,
> -	STM32_LPTIM_ENCODER_BOTH_EDGE,
> +	STM32_LPTIM_COUNTER_INCREASE = COUNTER_COUNT_FUNCTION_INCREASE,
> +	STM32_LPTIM_ENCODER_BOTH_EDGE = COUNTER_COUNT_FUNCTION_QUADRATURE_X4,
>  };
>  
>  static enum counter_count_function stm32_lptim_cnt_functions[] = {
> -	[STM32_LPTIM_COUNTER_INCREASE] = COUNTER_COUNT_FUNCTION_INCREASE,
> -	[STM32_LPTIM_ENCODER_BOTH_EDGE] = COUNTER_COUNT_FUNCTION_QUADRATURE_X4,
> +	STM32_LPTIM_COUNTER_INCREASE,
> +	STM32_LPTIM_ENCODER_BOTH_EDGE,
>  };
>  
>  enum stm32_lptim_synapse_action {
> +	/* Index must match with stm32_lptim_cnt_polarity[] (priv->polarity) */
>  	STM32_LPTIM_SYNAPSE_ACTION_RISING_EDGE,
>  	STM32_LPTIM_SYNAPSE_ACTION_FALLING_EDGE,
>  	STM32_LPTIM_SYNAPSE_ACTION_BOTH_EDGES,
>  	STM32_LPTIM_SYNAPSE_ACTION_NONE,
>  };
>  
> -static enum counter_synapse_action stm32_lptim_cnt_synapse_actions[] = {
> -	/* Index must match with stm32_lptim_cnt_polarity[] (priv->polarity) */
> +static const enum stm32_lptim_synapse_action stm32_lptim_c2l_actions_map[] = {
> +	[COUNTER_SYNAPSE_ACTION_RISING_EDGE] = STM32_LPTIM_SYNAPSE_ACTION_RISING_EDGE,
> +	[COUNTER_SYNAPSE_ACTION_FALLING_EDGE] = STM32_LPTIM_SYNAPSE_ACTION_FALLING_EDGE,
> +	[COUNTER_SYNAPSE_ACTION_BOTH_EDGES] = STM32_LPTIM_SYNAPSE_ACTION_BOTH_EDGES,
> +	[COUNTER_SYNAPSE_ACTION_NONE] = STM32_LPTIM_SYNAPSE_ACTION_NONE,
> +};
> +
> +static const enum counter_synapse_action stm32_lptim_l2c_actions_map[] = {
>  	[STM32_LPTIM_SYNAPSE_ACTION_RISING_EDGE] = COUNTER_SYNAPSE_ACTION_RISING_EDGE,
>  	[STM32_LPTIM_SYNAPSE_ACTION_FALLING_EDGE] = COUNTER_SYNAPSE_ACTION_FALLING_EDGE,
>  	[STM32_LPTIM_SYNAPSE_ACTION_BOTH_EDGES] = COUNTER_SYNAPSE_ACTION_BOTH_EDGES,
>  	[STM32_LPTIM_SYNAPSE_ACTION_NONE] = COUNTER_SYNAPSE_ACTION_NONE,
>  };
>  
> +static const enum counter_synapse_action stm32_lptim_cnt_synapse_actions[] = {
> +	stm32_lptim_l2c_actions_map[STM32_LPTIM_SYNAPSE_ACTION_RISING_EDGE],
> +	stm32_lptim_l2c_actions_map[STM32_LPTIM_SYNAPSE_ACTION_FALLING_EDGE],
> +	stm32_lptim_l2c_actions_map[STM32_LPTIM_SYNAPSE_ACTION_BOTH_EDGES],
> +	stm32_lptim_l2c_actions_map[STM32_LPTIM_SYNAPSE_ACTION_NONE],
> +};
> +
>  static int stm32_lptim_cnt_read(struct counter_device *counter,
>  				struct counter_count *count, unsigned long *val)
>  {
> @@ -394,7 +408,7 @@ static int stm32_lptim_cnt_read(struct counter_device *counter,
>  
>  static int stm32_lptim_cnt_function_get(struct counter_device *counter,
>  					struct counter_count *count,
> -					size_t *function)
> +					enum counter_count_function *function)
>  {
>  	struct stm32_lptim_cnt *const priv = counter->priv;
>  
> @@ -413,7 +427,7 @@ static int stm32_lptim_cnt_function_get(struct counter_device *counter,
>  
>  static int stm32_lptim_cnt_function_set(struct counter_device *counter,
>  					struct counter_count *count,
> -					size_t function)
> +					enum counter_count_function function)
>  {
>  	struct stm32_lptim_cnt *const priv = counter->priv;
>  
> @@ -423,19 +437,20 @@ static int stm32_lptim_cnt_function_set(struct counter_device *counter,
>  	switch (function) {
>  	case STM32_LPTIM_COUNTER_INCREASE:
>  		priv->quadrature_mode = 0;
> -		return 0;
> +		break;
>  	case STM32_LPTIM_ENCODER_BOTH_EDGE:
>  		priv->quadrature_mode = 1;
>  		priv->polarity = STM32_LPTIM_SYNAPSE_ACTION_BOTH_EDGES;
> -		return 0;
> +		break;
> +	default: return -EINVAL;
>  	}
>  
> -	return -EINVAL;
> +	return 0;
>  }
>  
> -static ssize_t stm32_lptim_cnt_enable_read(struct counter_device *counter,
> -					   struct counter_count *count,
> -					   void *private, char *buf)
> +static int stm32_lptim_cnt_enable_read(struct counter_device *counter,
> +				       struct counter_count *count,
> +				       bool *enable)
>  {
>  	struct stm32_lptim_cnt *const priv = counter->priv;
>  	int ret;
> @@ -444,22 +459,18 @@ static ssize_t stm32_lptim_cnt_enable_read(struct counter_device *counter,
>  	if (ret < 0)
>  		return ret;
>  
> -	return scnprintf(buf, PAGE_SIZE, "%u\n", ret);
> +	*enable = ret;
> +
> +	return 0;
>  }
>  
> -static ssize_t stm32_lptim_cnt_enable_write(struct counter_device *counter,
> -					    struct counter_count *count,
> -					    void *private,
> -					    const char *buf, size_t len)
> +static int stm32_lptim_cnt_enable_write(struct counter_device *counter,
> +					struct counter_count *count,
> +					bool enable)
>  {
>  	struct stm32_lptim_cnt *const priv = counter->priv;
> -	bool enable;
>  	int ret;
>  
> -	ret = kstrtobool(buf, &enable);
> -	if (ret)
> -		return ret;
> -
>  	/* Check nobody uses the timer, or already disabled/enabled */
>  	ret = stm32_lptim_is_enabled(priv);
>  	if ((ret < 0) || (!ret && !enable))
> @@ -475,48 +486,51 @@ static ssize_t stm32_lptim_cnt_enable_write(struct counter_device *counter,
>  	if (ret)
>  		return ret;
>  
> -	return len;
> +	return 0;
>  }
>  
> -static ssize_t stm32_lptim_cnt_ceiling_read(struct counter_device *counter,
> -					    struct counter_count *count,
> -					    void *private, char *buf)
> +static int stm32_lptim_cnt_ceiling_read(struct counter_device *counter,
> +					struct counter_count *count,
> +					unsigned long *ceiling)
>  {
>  	struct stm32_lptim_cnt *const priv = counter->priv;
>  
> -	return stm32_lptim_cnt_get_ceiling(priv, buf);
> +	*ceiling = priv->ceiling;
> +
> +	return 0;
>  }
>  
> -static ssize_t stm32_lptim_cnt_ceiling_write(struct counter_device *counter,
> -					     struct counter_count *count,
> -					     void *private,
> -					     const char *buf, size_t len)
> +static int stm32_lptim_cnt_ceiling_write(struct counter_device *counter,
> +					 struct counter_count *count,
> +					 unsigned long ceiling)
>  {
>  	struct stm32_lptim_cnt *const priv = counter->priv;
>  
> -	return stm32_lptim_cnt_set_ceiling(priv, buf, len);
> +	if (stm32_lptim_is_enabled(priv))
> +		return -EBUSY;
> +
> +	priv->ceiling = ceiling;
> +
> +	if (ceiling > STM32_LPTIM_MAX_ARR)
> +		return -EINVAL;
> +
> +	return 0;
>  }
>  
> -static const struct counter_count_ext stm32_lptim_cnt_ext[] = {
> -	{
> -		.name = "enable",
> -		.read = stm32_lptim_cnt_enable_read,
> -		.write = stm32_lptim_cnt_enable_write
> -	},
> -	{
> -		.name = "ceiling",
> -		.read = stm32_lptim_cnt_ceiling_read,
> -		.write = stm32_lptim_cnt_ceiling_write
> -	},
> +static struct counter_data stm32_lptim_cnt_ext[] = {
> +	COUNTER_DATA_ENABLE(stm32_lptim_cnt_enable_read,
> +			    stm32_lptim_cnt_enable_write),
> +	COUNTER_DATA_CEILING(stm32_lptim_cnt_ceiling_read,
> +			     stm32_lptim_cnt_ceiling_write),
>  };
>  
>  static int stm32_lptim_cnt_action_get(struct counter_device *counter,
>  				      struct counter_count *count,
>  				      struct counter_synapse *synapse,
> -				      size_t *action)
> +				      enum counter_synapse_action *action)
>  {
>  	struct stm32_lptim_cnt *const priv = counter->priv;
> -	size_t function;
> +	enum counter_count_function function;
>  	int err;
>  
>  	err = stm32_lptim_cnt_function_get(counter, count, &function);
> @@ -527,25 +541,27 @@ static int stm32_lptim_cnt_action_get(struct counter_device *counter,
>  	case STM32_LPTIM_COUNTER_INCREASE:
>  		/* LP Timer acts as up-counter on input 1 */
>  		if (synapse->signal->id == count->synapses[0].signal->id)
> -			*action = priv->polarity;
> +			*action = stm32_lptim_l2c_actions_map[priv->polarity];
>  		else
> -			*action = STM32_LPTIM_SYNAPSE_ACTION_NONE;
> -		return 0;
> +			*action = COUNTER_SYNAPSE_ACTION_NONE;
> +		break;
>  	case STM32_LPTIM_ENCODER_BOTH_EDGE:
> -		*action = priv->polarity;
> -		return 0;
> +		*action = stm32_lptim_l2c_actions_map[priv->polarity];
> +		break;
> +	default: return -EINVAL;
>  	}
>  
> -	return -EINVAL;
> +	return 0;
>  }
>  
>  static int stm32_lptim_cnt_action_set(struct counter_device *counter,
>  				      struct counter_count *count,
>  				      struct counter_synapse *synapse,
> -				      size_t action)
> +				      enum counter_synapse_action action)
>  {
>  	struct stm32_lptim_cnt *const priv = counter->priv;
> -	size_t function;
> +	enum counter_count_function function;
> +	enum stm32_lptim_cnt_function cnt_function;
>  	int err;
>  
>  	if (stm32_lptim_is_enabled(priv))
> @@ -554,29 +570,18 @@ static int stm32_lptim_cnt_action_set(struct counter_device *counter,
>  	err = stm32_lptim_cnt_function_get(counter, count, &function);
>  	if (err)
>  		return err;
> +	cnt_function = function;
>  
>  	/* only set polarity when in counter mode (on input 1) */
> -	if (function == STM32_LPTIM_COUNTER_INCREASE
> -	    && synapse->signal->id == count->synapses[0].signal->id) {
> -		switch (action) {
> -		case STM32_LPTIM_SYNAPSE_ACTION_RISING_EDGE:
> -		case STM32_LPTIM_SYNAPSE_ACTION_FALLING_EDGE:
> -		case STM32_LPTIM_SYNAPSE_ACTION_BOTH_EDGES:
> -			priv->polarity = action;
> -			return 0;
> -		}
> -	}
> +	if (cnt_function != STM32_LPTIM_COUNTER_INCREASE
> +	    || synapse->signal->id != count->synapses[0].signal->id
> +	    || action == COUNTER_SYNAPSE_ACTION_NONE)
> +		return -EINVAL;
>  
> -	return -EINVAL;
> -}
> +	priv->polarity = stm32_lptim_c2l_actions_map[action];
>  
> -static const struct counter_ops stm32_lptim_cnt_ops = {
> -	.count_read = stm32_lptim_cnt_read,
> -	.function_get = stm32_lptim_cnt_function_get,
> -	.function_set = stm32_lptim_cnt_function_set,
> -	.action_get = stm32_lptim_cnt_action_get,
> -	.action_set = stm32_lptim_cnt_action_set,
> -};
> +	return 0;
> +}
>  
>  static struct counter_signal stm32_lptim_cnt_signals[] = {
>  	{
> @@ -660,7 +665,11 @@ static int stm32_lptim_cnt_probe(struct platform_device *pdev)
>  	/* Initialize Counter device */
>  	priv->counter.name = dev_name(&pdev->dev);
>  	priv->counter.parent = &pdev->dev;
> -	priv->counter.ops = &stm32_lptim_cnt_ops;
> +	priv->counter.count_read = stm32_lptim_cnt_read;
> +	priv->counter.function_read = stm32_lptim_cnt_function_get;
> +	priv->counter.function_write = stm32_lptim_cnt_function_set;
> +	priv->counter.action_read = stm32_lptim_cnt_action_get;
> +	priv->counter.action_write = stm32_lptim_cnt_action_set;
>  	if (ddata->has_encoder) {
>  		priv->counter.counts = &stm32_lptim_enc_counts;
>  		priv->counter.num_signals = ARRAY_SIZE(stm32_lptim_cnt_signals);
> diff --git a/drivers/counter/stm32-timer-cnt.c b/drivers/counter/stm32-timer-cnt.c
> index ef2a974a2f10..09e87cf79ce9 100644
> --- a/drivers/counter/stm32-timer-cnt.c
> +++ b/drivers/counter/stm32-timer-cnt.c
> @@ -45,17 +45,17 @@ struct stm32_timer_cnt {
>   */
>  enum stm32_count_function {
>  	STM32_COUNT_SLAVE_MODE_DISABLED = -1,
> +	STM32_COUNT_ENCODER_MODE_1 = COUNTER_COUNT_FUNCTION_QUADRATURE_X2_A,
> +	STM32_COUNT_ENCODER_MODE_2 = COUNTER_COUNT_FUNCTION_QUADRATURE_X2_B,
> +	STM32_COUNT_ENCODER_MODE_3 = COUNTER_COUNT_FUNCTION_QUADRATURE_X4,
> +};
> +
> +static const enum counter_count_function stm32_count_functions[] = {
>  	STM32_COUNT_ENCODER_MODE_1,
>  	STM32_COUNT_ENCODER_MODE_2,
>  	STM32_COUNT_ENCODER_MODE_3,
>  };
>  
> -static enum counter_count_function stm32_count_functions[] = {
> -	[STM32_COUNT_ENCODER_MODE_1] = COUNTER_COUNT_FUNCTION_QUADRATURE_X2_A,
> -	[STM32_COUNT_ENCODER_MODE_2] = COUNTER_COUNT_FUNCTION_QUADRATURE_X2_B,
> -	[STM32_COUNT_ENCODER_MODE_3] = COUNTER_COUNT_FUNCTION_QUADRATURE_X4,
> -};
> -
>  static int stm32_count_read(struct counter_device *counter,
>  			    struct counter_count *count, unsigned long *val)
>  {
> @@ -82,7 +82,7 @@ static int stm32_count_write(struct counter_device *counter,
>  
>  static int stm32_count_function_get(struct counter_device *counter,
>  				    struct counter_count *count,
> -				    size_t *function)
> +				    enum counter_count_function *function)
>  {
>  	struct stm32_timer_cnt *const priv = counter->priv;
>  	u32 smcr;
> @@ -106,7 +106,7 @@ static int stm32_count_function_get(struct counter_device *counter,
>  
>  static int stm32_count_function_set(struct counter_device *counter,
>  				    struct counter_count *count,
> -				    size_t function)
> +				    enum counter_count_function function)
>  {
>  	struct stm32_timer_cnt *const priv = counter->priv;
>  	u32 cr1, sms;
> @@ -146,78 +146,66 @@ static int stm32_count_function_set(struct counter_device *counter,
>  	return 0;
>  }
>  
> -static ssize_t stm32_count_direction_read(struct counter_device *counter,
> +static int stm32_count_direction_read(struct counter_device *counter,
>  				      struct counter_count *count,
> -				      void *private, char *buf)
> +				      enum counter_count_direction *direction)
>  {
>  	struct stm32_timer_cnt *const priv = counter->priv;
> -	const char *direction;
>  	u32 cr1;
>  
>  	regmap_read(priv->regmap, TIM_CR1, &cr1);
> -	direction = (cr1 & TIM_CR1_DIR) ? "backward" : "forward";
> +	*direction = (cr1 & TIM_CR1_DIR) ? COUNTER_COUNT_DIRECTION_BACKWARD :
> +		COUNTER_COUNT_DIRECTION_FORWARD;
>  
> -	return scnprintf(buf, PAGE_SIZE, "%s\n", direction);
> +	return 0;
>  }
>  
> -static ssize_t stm32_count_ceiling_read(struct counter_device *counter,
> -					struct counter_count *count,
> -					void *private, char *buf)
> +static int stm32_count_ceiling_read(struct counter_device *counter,
> +				    struct counter_count *count,
> +				    unsigned long *ceiling)
>  {
>  	struct stm32_timer_cnt *const priv = counter->priv;
>  	u32 arr;
>  
>  	regmap_read(priv->regmap, TIM_ARR, &arr);
>  
> -	return snprintf(buf, PAGE_SIZE, "%u\n", arr);
> +	*ceiling = arr;
> +
> +	return 0;
>  }
>  
> -static ssize_t stm32_count_ceiling_write(struct counter_device *counter,
> -					 struct counter_count *count,
> -					 void *private,
> -					 const char *buf, size_t len)
> +static int stm32_count_ceiling_write(struct counter_device *counter,
> +				     struct counter_count *count,
> +				     unsigned long ceiling)
>  {
>  	struct stm32_timer_cnt *const priv = counter->priv;
> -	unsigned int ceiling;
> -	int ret;
> -
> -	ret = kstrtouint(buf, 0, &ceiling);
> -	if (ret)
> -		return ret;
>  
>  	/* TIMx_ARR register shouldn't be buffered (ARPE=0) */
>  	regmap_update_bits(priv->regmap, TIM_CR1, TIM_CR1_ARPE, 0);
>  	regmap_write(priv->regmap, TIM_ARR, ceiling);
>  
>  	priv->ceiling = ceiling;
> -	return len;
> +	return 0;
>  }
>  
> -static ssize_t stm32_count_enable_read(struct counter_device *counter,
> -				       struct counter_count *count,
> -				       void *private, char *buf)
> +static int stm32_count_enable_read(struct counter_device *counter,
> +				   struct counter_count *count, bool *enable)
>  {
>  	struct stm32_timer_cnt *const priv = counter->priv;
>  	u32 cr1;
>  
>  	regmap_read(priv->regmap, TIM_CR1, &cr1);
>  
> -	return scnprintf(buf, PAGE_SIZE, "%d\n", (bool)(cr1 & TIM_CR1_CEN));
> +	*enable = cr1 & TIM_CR1_CEN;
> +
> +	return 0;
>  }
>  
> -static ssize_t stm32_count_enable_write(struct counter_device *counter,
> -					struct counter_count *count,
> -					void *private,
> -					const char *buf, size_t len)
> +static int stm32_count_enable_write(struct counter_device *counter,
> +				    struct counter_count *count, bool enable)
>  {
>  	struct stm32_timer_cnt *const priv = counter->priv;
> -	int err;
>  	u32 cr1;
> -	bool enable;
> -
> -	err = kstrtobool(buf, &enable);
> -	if (err)
> -		return err;
>  
>  	if (enable) {
>  		regmap_read(priv->regmap, TIM_CR1, &cr1);
> @@ -236,46 +224,31 @@ static ssize_t stm32_count_enable_write(struct counter_device *counter,
>  	/* Keep enabled state to properly handle low power states */
>  	priv->enabled = enable;
>  
> -	return len;
> +	return 0;
>  }
>  
> -static const struct counter_count_ext stm32_count_ext[] = {
> -	{
> -		.name = "direction",
> -		.read = stm32_count_direction_read,
> -	},
> -	{
> -		.name = "enable",
> -		.read = stm32_count_enable_read,
> -		.write = stm32_count_enable_write
> -	},
> -	{
> -		.name = "ceiling",
> -		.read = stm32_count_ceiling_read,
> -		.write = stm32_count_ceiling_write
> -	},
> -};
> -
> -enum stm32_synapse_action {
> -	STM32_SYNAPSE_ACTION_NONE,
> -	STM32_SYNAPSE_ACTION_BOTH_EDGES
> +static struct counter_data stm32_count_ext[] = {
> +	COUNTER_DATA_DIRECTION(stm32_count_direction_read),
> +	COUNTER_DATA_ENABLE(stm32_count_enable_read, stm32_count_enable_write),
> +	COUNTER_DATA_CEILING(stm32_count_ceiling_read,
> +			     stm32_count_ceiling_write),
>  };
>  
> -static enum counter_synapse_action stm32_synapse_actions[] = {
> -	[STM32_SYNAPSE_ACTION_NONE] = COUNTER_SYNAPSE_ACTION_NONE,
> -	[STM32_SYNAPSE_ACTION_BOTH_EDGES] = COUNTER_SYNAPSE_ACTION_BOTH_EDGES
> +static const enum counter_synapse_action stm32_synapse_actions[] = {
> +	COUNTER_SYNAPSE_ACTION_NONE,
> +	COUNTER_SYNAPSE_ACTION_BOTH_EDGES
>  };
>  
>  static int stm32_action_get(struct counter_device *counter,
>  			    struct counter_count *count,
>  			    struct counter_synapse *synapse,
> -			    size_t *action)
> +			    enum counter_synapse_action *action)
>  {
> -	size_t function;
> +	enum counter_count_function function;
>  	int err;
>  
>  	/* Default action mode (e.g. STM32_COUNT_SLAVE_MODE_DISABLED) */
> -	*action = STM32_SYNAPSE_ACTION_NONE;
> +	*action = COUNTER_SYNAPSE_ACTION_NONE;
>  
>  	err = stm32_count_function_get(counter, count, &function);
>  	if (err)
> @@ -285,30 +258,23 @@ static int stm32_action_get(struct counter_device *counter,
>  	case STM32_COUNT_ENCODER_MODE_1:
>  		/* counts up/down on TI1FP1 edge depending on TI2FP2 level */
>  		if (synapse->signal->id == count->synapses[0].signal->id)
> -			*action = STM32_SYNAPSE_ACTION_BOTH_EDGES;
> +			*action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES;
>  		break;
>  	case STM32_COUNT_ENCODER_MODE_2:
>  		/* counts up/down on TI2FP2 edge depending on TI1FP1 level */
>  		if (synapse->signal->id == count->synapses[1].signal->id)
> -			*action = STM32_SYNAPSE_ACTION_BOTH_EDGES;
> +			*action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES;
>  		break;
>  	case STM32_COUNT_ENCODER_MODE_3:
>  		/* counts up/down on both TI1FP1 and TI2FP2 edges */
> -		*action = STM32_SYNAPSE_ACTION_BOTH_EDGES;
> +		*action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES;
>  		break;
> +	default: return -EINVAL;
>  	}
>  
>  	return 0;
>  }
>  
> -static const struct counter_ops stm32_timer_cnt_ops = {
> -	.count_read = stm32_count_read,
> -	.count_write = stm32_count_write,
> -	.function_get = stm32_count_function_get,
> -	.function_set = stm32_count_function_set,
> -	.action_get = stm32_action_get,
> -};
> -
>  static struct counter_signal stm32_signals[] = {
>  	{
>  		.id = 0,
> @@ -363,7 +329,11 @@ static int stm32_timer_cnt_probe(struct platform_device *pdev)
>  
>  	priv->counter.name = dev_name(dev);
>  	priv->counter.parent = dev;
> -	priv->counter.ops = &stm32_timer_cnt_ops;
> +	priv->counter.count_read = stm32_count_read;
> +	priv->counter.count_write = stm32_count_write;
> +	priv->counter.function_read = stm32_count_function_get;
> +	priv->counter.function_write = stm32_count_function_set;
> +	priv->counter.action_read = stm32_action_get;
>  	priv->counter.counts = &stm32_counts;
>  	priv->counter.num_counts = 1;
>  	priv->counter.signals = stm32_signals;
> diff --git a/drivers/counter/ti-eqep.c b/drivers/counter/ti-eqep.c
> index 1ff07faef27f..b1fac22a0a4f 100644
> --- a/drivers/counter/ti-eqep.c
> +++ b/drivers/counter/ti-eqep.c
> @@ -74,16 +74,10 @@ enum {
>  
>  /* Position Counter Input Modes */
>  enum {
> -	TI_EQEP_COUNT_FUNC_QUAD_COUNT,
> -	TI_EQEP_COUNT_FUNC_DIR_COUNT,
> -	TI_EQEP_COUNT_FUNC_UP_COUNT,
> -	TI_EQEP_COUNT_FUNC_DOWN_COUNT,
> -};
> -
> -enum {
> -	TI_EQEP_SYNAPSE_ACTION_BOTH_EDGES,
> -	TI_EQEP_SYNAPSE_ACTION_RISING_EDGE,
> -	TI_EQEP_SYNAPSE_ACTION_NONE,
> +	TI_EQEP_COUNT_FUNC_QUAD_COUNT	= COUNTER_COUNT_FUNCTION_QUADRATURE_X4,
> +	TI_EQEP_COUNT_FUNC_DIR_COUNT	= COUNTER_COUNT_FUNCTION_PULSE_DIRECTION,
> +	TI_EQEP_COUNT_FUNC_UP_COUNT	= COUNTER_COUNT_FUNCTION_INCREASE,
> +	TI_EQEP_COUNT_FUNC_DOWN_COUNT	= COUNTER_COUNT_FUNCTION_DECREASE,
>  };
>  
>  struct ti_eqep_cnt {
> @@ -118,7 +112,8 @@ static int ti_eqep_count_write(struct counter_device *counter,
>  }
>  
>  static int ti_eqep_function_get(struct counter_device *counter,
> -				struct counter_count *count, size_t *function)
> +				struct counter_count *count,
> +				enum counter_count_function *function)
>  {
>  	struct ti_eqep_cnt *priv = counter->priv;
>  	u32 qdecctl;
> @@ -130,7 +125,8 @@ static int ti_eqep_function_get(struct counter_device *counter,
>  }
>  
>  static int ti_eqep_function_set(struct counter_device *counter,
> -				struct counter_count *count, size_t function)
> +				struct counter_count *count,
> +				enum counter_count_function function)
>  {
>  	struct ti_eqep_cnt *priv = counter->priv;
>  
> @@ -140,10 +136,11 @@ static int ti_eqep_function_set(struct counter_device *counter,
>  
>  static int ti_eqep_action_get(struct counter_device *counter,
>  			      struct counter_count *count,
> -			      struct counter_synapse *synapse, size_t *action)
> +			      struct counter_synapse *synapse,
> +			      enum counter_synapse_action *action)
>  {
>  	struct ti_eqep_cnt *priv = counter->priv;
> -	size_t function;
> +	enum counter_count_function function;
>  	u32 qdecctl;
>  	int err;
>  
> @@ -156,7 +153,7 @@ static int ti_eqep_action_get(struct counter_device *counter,
>  		/* In quadrature mode, the rising and falling edge of both
>  		 * QEPA and QEPB trigger QCLK.
>  		 */
> -		*action = TI_EQEP_SYNAPSE_ACTION_BOTH_EDGES;
> +		*action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES;
>  		break;
>  	case TI_EQEP_COUNT_FUNC_DIR_COUNT:
>  		/* In direction-count mode only rising edge of QEPA is counted
> @@ -164,10 +161,10 @@ static int ti_eqep_action_get(struct counter_device *counter,
>  		 */
>  		switch (synapse->signal->id) {
>  		case TI_EQEP_SIGNAL_QEPA:
> -			*action = TI_EQEP_SYNAPSE_ACTION_RISING_EDGE;
> +			*action = COUNTER_SYNAPSE_ACTION_RISING_EDGE;
>  			break;
>  		default:
> -			*action = TI_EQEP_SYNAPSE_ACTION_NONE;
> +			*action = COUNTER_SYNAPSE_ACTION_NONE;
>  			break;
>  		}
>  		break;
> @@ -183,134 +180,103 @@ static int ti_eqep_action_get(struct counter_device *counter,
>  				return err;
>  
>  			if (qdecctl & QDECCTL_XCR)
> -				*action = TI_EQEP_SYNAPSE_ACTION_BOTH_EDGES;
> +				*action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES;
>  			else
> -				*action = TI_EQEP_SYNAPSE_ACTION_RISING_EDGE;
> +				*action = COUNTER_SYNAPSE_ACTION_RISING_EDGE;
>  			break;
>  		default:
> -			*action = TI_EQEP_SYNAPSE_ACTION_NONE;
> +			*action = COUNTER_SYNAPSE_ACTION_NONE;
>  			break;
>  		}
>  		break;
> +	default: return -EINVAL;
>  	}
>  
>  	return 0;
>  }
>  
> -static const struct counter_ops ti_eqep_counter_ops = {
> -	.count_read	= ti_eqep_count_read,
> -	.count_write	= ti_eqep_count_write,
> -	.function_get	= ti_eqep_function_get,
> -	.function_set	= ti_eqep_function_set,
> -	.action_get	= ti_eqep_action_get,
> -};
> -
> -static ssize_t ti_eqep_position_ceiling_read(struct counter_device *counter,
> -					     struct counter_count *count,
> -					     void *ext_priv, char *buf)
> +static int ti_eqep_position_ceiling_read(struct counter_device *counter,
> +					 struct counter_count *count,
> +					 unsigned long *ceiling)
>  {
>  	struct ti_eqep_cnt *priv = counter->priv;
>  	u32 qposmax;
>  
>  	regmap_read(priv->regmap32, QPOSMAX, &qposmax);
>  
> -	return sprintf(buf, "%u\n", qposmax);
> +	*ceiling = qposmax;
> +
> +	return 0;
>  }
>  
> -static ssize_t ti_eqep_position_ceiling_write(struct counter_device *counter,
> -					      struct counter_count *count,
> -					      void *ext_priv, const char *buf,
> -					      size_t len)
> +static int ti_eqep_position_ceiling_write(struct counter_device *counter,
> +					  struct counter_count *count,
> +					  unsigned long ceiling)
>  {
>  	struct ti_eqep_cnt *priv = counter->priv;
> -	int err;
> -	u32 res;
>  
> -	err = kstrtouint(buf, 0, &res);
> -	if (err < 0)
> -		return err;
> +	regmap_write(priv->regmap32, QPOSMAX, ceiling);
>  
> -	regmap_write(priv->regmap32, QPOSMAX, res);
> -
> -	return len;
> +	return 0;
>  }
>  
> -static ssize_t ti_eqep_position_floor_read(struct counter_device *counter,
> -					   struct counter_count *count,
> -					   void *ext_priv, char *buf)
> +static int ti_eqep_position_floor_read(struct counter_device *counter,
> +				       struct counter_count *count,
> +				       unsigned long *floor)
>  {
>  	struct ti_eqep_cnt *priv = counter->priv;
>  	u32 qposinit;
>  
>  	regmap_read(priv->regmap32, QPOSINIT, &qposinit);
>  
> -	return sprintf(buf, "%u\n", qposinit);
> +	*floor = qposinit;
> +
> +	return 0;
>  }
>  
> -static ssize_t ti_eqep_position_floor_write(struct counter_device *counter,
> -					    struct counter_count *count,
> -					    void *ext_priv, const char *buf,
> -					    size_t len)
> +static int ti_eqep_position_floor_write(struct counter_device *counter,
> +					struct counter_count *count,
> +					unsigned long floor)
>  {
>  	struct ti_eqep_cnt *priv = counter->priv;
> -	int err;
> -	u32 res;
>  
> -	err = kstrtouint(buf, 0, &res);
> -	if (err < 0)
> -		return err;
> +	regmap_write(priv->regmap32, QPOSINIT, floor);
>  
> -	regmap_write(priv->regmap32, QPOSINIT, res);
> -
> -	return len;
> +	return 0;
>  }
>  
> -static ssize_t ti_eqep_position_enable_read(struct counter_device *counter,
> -					    struct counter_count *count,
> -					    void *ext_priv, char *buf)
> +static int ti_eqep_position_enable_read(struct counter_device *counter,
> +					struct counter_count *count,
> +					bool *enable)
>  {
>  	struct ti_eqep_cnt *priv = counter->priv;
>  	u32 qepctl;
>  
>  	regmap_read(priv->regmap16, QEPCTL, &qepctl);
>  
> -	return sprintf(buf, "%u\n", !!(qepctl & QEPCTL_PHEN));
> +	*enable = !!(qepctl & QEPCTL_PHEN);
> +
> +	return 0;
>  }
>  
> -static ssize_t ti_eqep_position_enable_write(struct counter_device *counter,
> -					     struct counter_count *count,
> -					     void *ext_priv, const char *buf,
> -					     size_t len)
> +static int ti_eqep_position_enable_write(struct counter_device *counter,
> +					 struct counter_count *count,
> +					 bool enable)
>  {
>  	struct ti_eqep_cnt *priv = counter->priv;
> -	int err;
> -	bool res;
>  
> -	err = kstrtobool(buf, &res);
> -	if (err < 0)
> -		return err;
> -
> -	regmap_write_bits(priv->regmap16, QEPCTL, QEPCTL_PHEN, res ? -1 : 0);
> +	regmap_write_bits(priv->regmap16, QEPCTL, QEPCTL_PHEN, enable ? -1 : 0);
>  
> -	return len;
> +	return 0;
>  }
>  
> -static struct counter_count_ext ti_eqep_position_ext[] = {
> -	{
> -		.name	= "ceiling",
> -		.read	= ti_eqep_position_ceiling_read,
> -		.write	= ti_eqep_position_ceiling_write,
> -	},
> -	{
> -		.name	= "floor",
> -		.read	= ti_eqep_position_floor_read,
> -		.write	= ti_eqep_position_floor_write,
> -	},
> -	{
> -		.name	= "enable",
> -		.read	= ti_eqep_position_enable_read,
> -		.write	= ti_eqep_position_enable_write,
> -	},
> +static struct counter_data ti_eqep_position_ext[] = {
> +	COUNTER_DATA_CEILING(ti_eqep_position_ceiling_read,
> +			     ti_eqep_position_ceiling_write),
> +	COUNTER_DATA_FLOOR(ti_eqep_position_floor_read,
> +			   ti_eqep_position_floor_write),
> +	COUNTER_DATA_ENABLE(ti_eqep_position_enable_read,
> +			    ti_eqep_position_enable_write),
>  };
>  
>  static struct counter_signal ti_eqep_signals[] = {
> @@ -325,16 +291,16 @@ static struct counter_signal ti_eqep_signals[] = {
>  };
>  
>  static const enum counter_count_function ti_eqep_position_functions[] = {
> -	[TI_EQEP_COUNT_FUNC_QUAD_COUNT]	= COUNTER_COUNT_FUNCTION_QUADRATURE_X4,
> -	[TI_EQEP_COUNT_FUNC_DIR_COUNT]	= COUNTER_COUNT_FUNCTION_PULSE_DIRECTION,
> -	[TI_EQEP_COUNT_FUNC_UP_COUNT]	= COUNTER_COUNT_FUNCTION_INCREASE,
> -	[TI_EQEP_COUNT_FUNC_DOWN_COUNT]	= COUNTER_COUNT_FUNCTION_DECREASE,
> +	TI_EQEP_COUNT_FUNC_QUAD_COUNT,
> +	TI_EQEP_COUNT_FUNC_DIR_COUNT,
> +	TI_EQEP_COUNT_FUNC_UP_COUNT,
> +	TI_EQEP_COUNT_FUNC_DOWN_COUNT,
>  };
>  
>  static const enum counter_synapse_action ti_eqep_position_synapse_actions[] = {
> -	[TI_EQEP_SYNAPSE_ACTION_BOTH_EDGES]	= COUNTER_SYNAPSE_ACTION_BOTH_EDGES,
> -	[TI_EQEP_SYNAPSE_ACTION_RISING_EDGE]	= COUNTER_SYNAPSE_ACTION_RISING_EDGE,
> -	[TI_EQEP_SYNAPSE_ACTION_NONE]		= COUNTER_SYNAPSE_ACTION_NONE,
> +	COUNTER_SYNAPSE_ACTION_BOTH_EDGES,
> +	COUNTER_SYNAPSE_ACTION_RISING_EDGE,
> +	COUNTER_SYNAPSE_ACTION_NONE,
>  };
>  
>  static struct counter_synapse ti_eqep_position_synapses[] = {
> @@ -406,7 +372,11 @@ static int ti_eqep_probe(struct platform_device *pdev)
>  
>  	priv->counter.name = dev_name(dev);
>  	priv->counter.parent = dev;
> -	priv->counter.ops = &ti_eqep_counter_ops;
> +	priv->counter.count_read = ti_eqep_count_read;
> +	priv->counter.count_write = ti_eqep_count_write;
> +	priv->counter.function_read = ti_eqep_function_get;
> +	priv->counter.function_write = ti_eqep_function_set;
> +	priv->counter.action_read = ti_eqep_action_get;
>  	priv->counter.counts = ti_eqep_counts;
>  	priv->counter.num_counts = ARRAY_SIZE(ti_eqep_counts);
>  	priv->counter.signals = ti_eqep_signals;
> diff --git a/include/linux/counter.h b/include/linux/counter.h
> index 9dbd5df4cd34..d628c7eaf754 100644
> --- a/include/linux/counter.h
> +++ b/include/linux/counter.h
> @@ -6,449 +6,286 @@
>  #ifndef _COUNTER_H_
>  #define _COUNTER_H_
>  
> -#include <linux/counter_enum.h>
>  #include <linux/device.h>
> +#include <linux/kernel.h>
> +#include <linux/list.h>
>  #include <linux/types.h>
> +#include <uapi/linux/counter-types.h>
>  
> -enum counter_count_direction {
> -	COUNTER_COUNT_DIRECTION_FORWARD = 0,
> -	COUNTER_COUNT_DIRECTION_BACKWARD
> -};
> -extern const char *const counter_count_direction_str[2];
> -
> -enum counter_count_mode {
> -	COUNTER_COUNT_MODE_NORMAL = 0,
> -	COUNTER_COUNT_MODE_RANGE_LIMIT,
> -	COUNTER_COUNT_MODE_NON_RECYCLE,
> -	COUNTER_COUNT_MODE_MODULO_N
> -};
> -extern const char *const counter_count_mode_str[4];
> -
> -struct counter_device;
> -struct counter_signal;
> -
> -/**
> - * struct counter_signal_ext - Counter Signal extensions
> - * @name:	attribute name
> - * @read:	read callback for this attribute; may be NULL
> - * @write:	write callback for this attribute; may be NULL
> - * @priv:	data private to the driver
> - */
> -struct counter_signal_ext {
> +struct counter_data {
> +	enum counter_data_type type;
>  	const char *name;
> -	ssize_t (*read)(struct counter_device *counter,
> -			struct counter_signal *signal, void *priv, char *buf);
> -	ssize_t (*write)(struct counter_device *counter,
> -			 struct counter_signal *signal, void *priv,
> -			 const char *buf, size_t len);
> +	void *read;
> +	void *write;
>  	void *priv;
>  };
>  
>  /**
>   * struct counter_signal - Counter Signal node
> - * @id:		unique ID used to identify signal
> - * @name:	device-specific Signal name; ideally, this should match the name
> - *		as it appears in the datasheet documentation
> - * @ext:	optional array of Counter Signal extensions
> - * @num_ext:	number of Counter Signal extensions specified in @ext
> - * @priv:	optional private data supplied by driver
> + * @id:		unique ID used to identify the Signal
> + * @name:	device-specific Signal name
> + * @ext:	optional array of Signal extensions
> + * @num_ext:	number of Signal extensions specified in @ext
>   */
>  struct counter_signal {
>  	int id;
>  	const char *name;
>  
> -	const struct counter_signal_ext *ext;
> +	struct counter_data *ext;
>  	size_t num_ext;
> -
> -	void *priv;
> -};
> -
> -/**
> - * struct counter_signal_enum_ext - Signal enum extension attribute
> - * @items:	Array of strings
> - * @num_items:	Number of items specified in @items
> - * @set:	Set callback function; may be NULL
> - * @get:	Get callback function; may be NULL
> - *
> - * The counter_signal_enum_ext structure can be used to implement enum style
> - * Signal extension attributes. Enum style attributes are those which have a set
> - * of strings that map to unsigned integer values. The Generic Counter Signal
> - * enum extension helper code takes care of mapping between value and string, as
> - * well as generating a "_available" file which contains a list of all available
> - * items. The get callback is used to query the currently active item; the index
> - * of the item within the respective items array is returned via the 'item'
> - * parameter. The set callback is called when the attribute is updated; the
> - * 'item' parameter contains the index of the newly activated item within the
> - * respective items array.
> - */
> -struct counter_signal_enum_ext {
> -	const char * const *items;
> -	size_t num_items;
> -	int (*get)(struct counter_device *counter,
> -		   struct counter_signal *signal, size_t *item);
> -	int (*set)(struct counter_device *counter,
> -		   struct counter_signal *signal, size_t item);
> -};
> -
> -/**
> - * COUNTER_SIGNAL_ENUM() - Initialize Signal enum extension
> - * @_name:	Attribute name
> - * @_e:		Pointer to a counter_signal_enum_ext structure
> - *
> - * This should usually be used together with COUNTER_SIGNAL_ENUM_AVAILABLE()
> - */
> -#define COUNTER_SIGNAL_ENUM(_name, _e) \
> -{ \
> -	.name = (_name), \
> -	.read = counter_signal_enum_read, \
> -	.write = counter_signal_enum_write, \
> -	.priv = (_e) \
> -}
> -
> -/**
> - * COUNTER_SIGNAL_ENUM_AVAILABLE() - Initialize Signal enum available extension
> - * @_name:	Attribute name ("_available" will be appended to the name)
> - * @_e:		Pointer to a counter_signal_enum_ext structure
> - *
> - * Creates a read only attribute that lists all the available enum items in a
> - * newline separated list. This should usually be used together with
> - * COUNTER_SIGNAL_ENUM()
> - */
> -#define COUNTER_SIGNAL_ENUM_AVAILABLE(_name, _e) \
> -{ \
> -	.name = (_name "_available"), \
> -	.read = counter_signal_enum_available_read, \
> -	.priv = (_e) \
> -}
> -
> -enum counter_synapse_action {
> -	COUNTER_SYNAPSE_ACTION_NONE = 0,
> -	COUNTER_SYNAPSE_ACTION_RISING_EDGE,
> -	COUNTER_SYNAPSE_ACTION_FALLING_EDGE,
> -	COUNTER_SYNAPSE_ACTION_BOTH_EDGES
>  };
>  
>  /**
>   * struct counter_synapse - Counter Synapse node
> - * @action:		index of current action mode
>   * @actions_list:	array of available action modes
>   * @num_actions:	number of action modes specified in @actions_list
> - * @signal:		pointer to associated signal
> + * @signal:		pointer to the associated Signal
>   */
>  struct counter_synapse {
> -	size_t action;
>  	const enum counter_synapse_action *actions_list;
>  	size_t num_actions;
>  
>  	struct counter_signal *signal;
>  };
>  
> -struct counter_count;
> -
> -/**
> - * struct counter_count_ext - Counter Count extension
> - * @name:	attribute name
> - * @read:	read callback for this attribute; may be NULL
> - * @write:	write callback for this attribute; may be NULL
> - * @priv:	data private to the driver
> - */
> -struct counter_count_ext {
> -	const char *name;
> -	ssize_t (*read)(struct counter_device *counter,
> -			struct counter_count *count, void *priv, char *buf);
> -	ssize_t (*write)(struct counter_device *counter,
> -			 struct counter_count *count, void *priv,
> -			 const char *buf, size_t len);
> -	void *priv;
> -};
> -
> -enum counter_count_function {
> -	COUNTER_COUNT_FUNCTION_INCREASE = 0,
> -	COUNTER_COUNT_FUNCTION_DECREASE,
> -	COUNTER_COUNT_FUNCTION_PULSE_DIRECTION,
> -	COUNTER_COUNT_FUNCTION_QUADRATURE_X1_A,
> -	COUNTER_COUNT_FUNCTION_QUADRATURE_X1_B,
> -	COUNTER_COUNT_FUNCTION_QUADRATURE_X2_A,
> -	COUNTER_COUNT_FUNCTION_QUADRATURE_X2_B,
> -	COUNTER_COUNT_FUNCTION_QUADRATURE_X4
> -};
> -
>  /**
>   * struct counter_count - Counter Count node
> - * @id:			unique ID used to identify Count
> - * @name:		device-specific Count name; ideally, this should match
> - *			the name as it appears in the datasheet documentation
> - * @function:		index of current function mode
> - * @functions_list:	array available function modes
> + * @id:			unique ID used to identify the Count
> + * @name:		device-specific Count name
> + * @functions_list:	array of available function modes
>   * @num_functions:	number of function modes specified in @functions_list
> - * @synapses:		array of synapses for initialization
> - * @num_synapses:	number of synapses specified in @synapses
> - * @ext:		optional array of Counter Count extensions
> - * @num_ext:		number of Counter Count extensions specified in @ext
> - * @priv:		optional private data supplied by driver
> + * @synapses:		array of Synapses for initialization
> + * @num_synapses:	number of Synapses specified in @synapses
> + * @ext:		optional array of Count extensions
> + * @num_ext:		number of Count extensions specified in @ext
>   */
>  struct counter_count {
>  	int id;
>  	const char *name;
>  
> -	size_t function;
>  	const enum counter_count_function *functions_list;
>  	size_t num_functions;
>  
>  	struct counter_synapse *synapses;
>  	size_t num_synapses;
>  
> -	const struct counter_count_ext *ext;
> +	struct counter_data *ext;
>  	size_t num_ext;
> -
> -	void *priv;
> -};
> -
> -/**
> - * struct counter_count_enum_ext - Count enum extension attribute
> - * @items:	Array of strings
> - * @num_items:	Number of items specified in @items
> - * @set:	Set callback function; may be NULL
> - * @get:	Get callback function; may be NULL
> - *
> - * The counter_count_enum_ext structure can be used to implement enum style
> - * Count extension attributes. Enum style attributes are those which have a set
> - * of strings that map to unsigned integer values. The Generic Counter Count
> - * enum extension helper code takes care of mapping between value and string, as
> - * well as generating a "_available" file which contains a list of all available
> - * items. The get callback is used to query the currently active item; the index
> - * of the item within the respective items array is returned via the 'item'
> - * parameter. The set callback is called when the attribute is updated; the
> - * 'item' parameter contains the index of the newly activated item within the
> - * respective items array.
> - */
> -struct counter_count_enum_ext {
> -	const char * const *items;
> -	size_t num_items;
> -	int (*get)(struct counter_device *counter, struct counter_count *count,
> -		   size_t *item);
> -	int (*set)(struct counter_device *counter, struct counter_count *count,
> -		   size_t item);
>  };
>  
>  /**
> - * COUNTER_COUNT_ENUM() - Initialize Count enum extension
> - * @_name:	Attribute name
> - * @_e:		Pointer to a counter_count_enum_ext structure
> - *
> - * This should usually be used together with COUNTER_COUNT_ENUM_AVAILABLE()
> - */
> -#define COUNTER_COUNT_ENUM(_name, _e) \
> -{ \
> -	.name = (_name), \
> -	.read = counter_count_enum_read, \
> -	.write = counter_count_enum_write, \
> -	.priv = (_e) \
> -}
> -
> -/**
> - * COUNTER_COUNT_ENUM_AVAILABLE() - Initialize Count enum available extension
> - * @_name:	Attribute name ("_available" will be appended to the name)
> - * @_e:		Pointer to a counter_count_enum_ext structure
> - *
> - * Creates a read only attribute that lists all the available enum items in a
> - * newline separated list. This should usually be used together with
> - * COUNTER_COUNT_ENUM()
> - */
> -#define COUNTER_COUNT_ENUM_AVAILABLE(_name, _e) \
> -{ \
> -	.name = (_name "_available"), \
> -	.read = counter_count_enum_available_read, \
> -	.priv = (_e) \
> -}
> -
> -/**
> - * struct counter_device_attr_group - internal container for attribute group
> + * struct counter_attribute_group - internal container for attribute group
>   * @attr_group:	Counter sysfs attributes group
>   * @attr_list:	list to keep track of created Counter sysfs attributes
>   * @num_attr:	number of Counter sysfs attributes
>   */
> -struct counter_device_attr_group {
> +struct counter_attribute_group {
>  	struct attribute_group attr_group;
>  	struct list_head attr_list;
>  	size_t num_attr;
>  };
>  
>  /**
> - * struct counter_device_state - internal state container for a Counter device
> + * struct counter_device - Counter data structure
> + * @name:		name of the device
> + * @parent:		optional parent device providing the counters
> + * @signal_read:	optional read callback for Signals. The read value of
> + *			the respective Signal should be passed back via the
> + *			value parameter.
> + * @count_read:		optional read callback for Counts. The read value of the
> + *			respective Count should be passed back via the value
> + *			parameter.
> + * @count_write:	optional write callback for Counts. The write value for
> + *			the respective Count is passed in via the value
> + *			parameter.
> + * @function_read:	optional read callback the Count function modes. The
> + *			read function mode of the respective Count should be
> + *			passed back via the function parameter.
> + * @function_write:	option write callback for Count function modes. The
> + *			function mode to write for the respective Count is
> + *			passed in via the function parameter.
> + * @action_read:	optional read callback the Synapse action modes. The
> + *			read action mode of the respective Synapse should be
> + *			passed back via the action parameter.
> + * @action_write:	option write callback for Synapse action modes. The
> + *			action mode to write for the respective Synapse is
> + *			passed in via the action parameter.
> + * @signals:		array of Signals
> + * @num_signals:	number of Signals specified in @signals
> + * @counts:		array of Counts
> + * @num_counts:		number of Counts specified in @counts
> + * @ext:		optional array of Counter device extensions
> + * @num_ext:		number of Counter device extensions specified in @ext
> + * @priv:		optional private data supplied by driver
>   * @id:			unique ID used to identify the Counter
>   * @dev:		internal device structure
> + * @synapse_names_list:	Synapse names list
>   * @groups_list:	attribute groups list (for Signals, Counts, and ext)
>   * @num_groups:		number of attribute groups containers
>   * @groups:		Counter sysfs attribute groups (to populate @dev.groups)
>   */
> -struct counter_device_state {
> +struct counter_device {
> +	const char *name;
> +	struct device *parent;
> +
> +	int (*signal_read)(struct counter_device *counter,
> +			   struct counter_signal *signal,
> +			   enum counter_signal_value *value);
> +	int (*count_read)(struct counter_device *counter,
> +			  struct counter_count *count, unsigned long *value);
> +	int (*count_write)(struct counter_device *counter,
> +			   struct counter_count *count, unsigned long value);
> +	int (*function_read)(struct counter_device *counter,
> +			     struct counter_count *count,
> +			     enum counter_count_function *function);
> +	int (*function_write)(struct counter_device *counter,
> +			      struct counter_count *count,
> +			      enum counter_count_function function);
> +	int (*action_read)(struct counter_device *counter,
> +			   struct counter_count *count,
> +			   struct counter_synapse *synapse,
> +			   enum counter_synapse_action *action);
> +	int (*action_write)(struct counter_device *counter,
> +			    struct counter_count *count,
> +			    struct counter_synapse *synapse,
> +			    enum counter_synapse_action action);
> +
> +	struct counter_signal *signals;
> +	size_t num_signals;
> +	struct counter_count *counts;
> +	size_t num_counts;
> +
> +	struct counter_data *ext;
> +	size_t num_ext;
> +
> +	void *priv;
> +
>  	int id;
>  	struct device dev;
> -	struct counter_device_attr_group *groups_list;
> +	struct list_head synapse_names_list;
> +	struct counter_attribute_group *groups_list;
>  	size_t num_groups;
>  	const struct attribute_group **groups;
>  };
>  
> -enum counter_signal_value {
> -	COUNTER_SIGNAL_LOW = 0,
> -	COUNTER_SIGNAL_HIGH
> -};
> +int counter_register(struct counter_device *const counter);
> +void counter_unregister(struct counter_device *const counter);
> +int devm_counter_register(struct device *dev,
> +			  struct counter_device *const counter);
> +void devm_counter_unregister(struct device *dev,
> +			     struct counter_device *const counter);
>  
> -/**
> - * struct counter_ops - Callbacks from driver
> - * @signal_read:	optional read callback for Signal attribute. The read
> - *			value of the respective Signal should be passed back via
> - *			the val parameter.
> - * @count_read:		optional read callback for Count attribute. The read
> - *			value of the respective Count should be passed back via
> - *			the val parameter.
> - * @count_write:	optional write callback for Count attribute. The write
> - *			value for the respective Count is passed in via the val
> - *			parameter.
> - * @function_get:	function to get the current count function mode. Returns
> - *			0 on success and negative error code on error. The index
> - *			of the respective Count's returned function mode should
> - *			be passed back via the function parameter.
> - * @function_set:	function to set the count function mode. function is the
> - *			index of the requested function mode from the respective
> - *			Count's functions_list array.
> - * @action_get:		function to get the current action mode. Returns 0 on
> - *			success and negative error code on error. The index of
> - *			the respective Synapse's returned action mode should be
> - *			passed back via the action parameter.
> - * @action_set:		function to set the action mode. action is the index of
> - *			the requested action mode from the respective Synapse's
> - *			actions_list array.
> - */
> -struct counter_ops {
> -	int (*signal_read)(struct counter_device *counter,
> -			   struct counter_signal *signal,
> -			   enum counter_signal_value *val);
> -	int (*count_read)(struct counter_device *counter,
> -			  struct counter_count *count, unsigned long *val);
> -	int (*count_write)(struct counter_device *counter,
> -			   struct counter_count *count, unsigned long val);
> -	int (*function_get)(struct counter_device *counter,
> -			    struct counter_count *count, size_t *function);
> -	int (*function_set)(struct counter_device *counter,
> -			    struct counter_count *count, size_t function);
> -	int (*action_get)(struct counter_device *counter,
> -			  struct counter_count *count,
> -			  struct counter_synapse *synapse, size_t *action);
> -	int (*action_set)(struct counter_device *counter,
> -			  struct counter_count *count,
> -			  struct counter_synapse *synapse, size_t action);
> -};
> +#define COUNTER_DATA_BOOL(_name, _read, _write) \
> +{ \
> +	.type = COUNTER_DATA_TYPE_BOOL, \
> +	.name = (_name), \
> +	.read = (_read), \
> +	.write = (_write), \
> +}
>  
> -/**
> - * struct counter_device_ext - Counter device extension
> - * @name:	attribute name
> - * @read:	read callback for this attribute; may be NULL
> - * @write:	write callback for this attribute; may be NULL
> - * @priv:	data private to the driver
> - */
> -struct counter_device_ext {
> -	const char *name;
> -	ssize_t (*read)(struct counter_device *counter, void *priv, char *buf);
> -	ssize_t (*write)(struct counter_device *counter, void *priv,
> -			 const char *buf, size_t len);
> -	void *priv;
> +#define COUNTER_DATA_UNSIGNED_LONG(_name, _read, _write) \
> +{ \
> +	.type = COUNTER_DATA_TYPE_UNSIGNED_LONG, \
> +	.name = (_name), \
> +	.read = (_read), \
> +	.write = (_write), \
> +}
> +
> +#define COUNTER_DATA_STRING(_name, _read, _write) \
> +{ \
> +	.type = COUNTER_DATA_TYPE_STRING, \
> +	.name = (_name), \
> +	.read = (_read), \
> +	.write = (_write), \
> +}
> +
> +struct counter_available {
> +	void *items;
> +	size_t num_items;
>  };
>  
> -/**
> - * struct counter_device_enum_ext - Counter enum extension attribute
> - * @items:	Array of strings
> - * @num_items:	Number of items specified in @items
> - * @set:	Set callback function; may be NULL
> - * @get:	Get callback function; may be NULL
> - *
> - * The counter_device_enum_ext structure can be used to implement enum style
> - * Counter extension attributes. Enum style attributes are those which have a
> - * set of strings that map to unsigned integer values. The Generic Counter enum
> - * extension helper code takes care of mapping between value and string, as well
> - * as generating a "_available" file which contains a list of all available
> - * items. The get callback is used to query the currently active item; the index
> - * of the item within the respective items array is returned via the 'item'
> - * parameter. The set callback is called when the attribute is updated; the
> - * 'item' parameter contains the index of the newly activated item within the
> - * respective items array.
> - */
> -struct counter_device_enum_ext {
> +#define DEFINE_COUNTER_AVAILABLE(_name, _items) \
> +	struct counter_available _name = { \
> +		.items = (_items), \
> +		.num_items = ARRAY_SIZE(_items), \
> +	}
> +
> +struct counter_enum {
>  	const char * const *items;
>  	size_t num_items;
> -	int (*get)(struct counter_device *counter, size_t *item);
> -	int (*set)(struct counter_device *counter, size_t item);
>  };
>  
> -/**
> - * COUNTER_DEVICE_ENUM() - Initialize Counter enum extension
> - * @_name:	Attribute name
> - * @_e:		Pointer to a counter_device_enum_ext structure
> - *
> - * This should usually be used together with COUNTER_DEVICE_ENUM_AVAILABLE()
> - */
> -#define COUNTER_DEVICE_ENUM(_name, _e) \
> +#define DEFINE_COUNTER_ENUM(_name, _items) \
> +	struct counter_enum _name = { \
> +		.items = (_items), \
> +		.num_items = ARRAY_SIZE(_items), \
> +	}
> +
> +#define COUNTER_DATA_ENUM(_name, _get, _set, _enum) \
>  { \
> +	.type = COUNTER_DATA_TYPE_ENUM, \
>  	.name = (_name), \
> -	.read = counter_device_enum_read, \
> -	.write = counter_device_enum_write, \
> -	.priv = (_e) \
> +	.read = (_get), \
> +	.write = (_set), \
> +	.priv = &(_enum), \
>  }
>  
> -/**
> - * COUNTER_DEVICE_ENUM_AVAILABLE() - Initialize Counter enum available extension
> - * @_name:	Attribute name ("_available" will be appended to the name)
> - * @_e:		Pointer to a counter_device_enum_ext structure
> - *
> - * Creates a read only attribute that lists all the available enum items in a
> - * newline separated list. This should usually be used together with
> - * COUNTER_DEVICE_ENUM()
> - */
> -#define COUNTER_DEVICE_ENUM_AVAILABLE(_name, _e) \
> +#define COUNTER_DATA_ENUM_AVAILABLE(_name, _read, _enum) \
>  { \
> +	.type = COUNTER_DATA_TYPE_ENUM_AVAILABLE, \
>  	.name = (_name "_available"), \
> -	.read = counter_device_enum_available_read, \
> -	.priv = (_e) \
> +	.read = (_read), \
> +	.priv = &(_enum), \
>  }
>  
> -/**
> - * struct counter_device - Counter data structure
> - * @name:		name of the device as it appears in the datasheet
> - * @parent:		optional parent device providing the counters
> - * @device_state:	internal device state container
> - * @ops:		callbacks from driver
> - * @signals:		array of Signals
> - * @num_signals:	number of Signals specified in @signals
> - * @counts:		array of Counts
> - * @num_counts:		number of Counts specified in @counts
> - * @ext:		optional array of Counter device extensions
> - * @num_ext:		number of Counter device extensions specified in @ext
> - * @priv:		optional private data supplied by driver
> - */
> -struct counter_device {
> -	const char *name;
> -	struct device *parent;
> -	struct counter_device_state *device_state;
> +#define COUNTER_DATA_ENUM_AND_AVAILABLE(_name, _get, _set, _enum) \
> +	COUNTER_DATA_ENUM(_name, _get, _set, _enum), \
> +	COUNTER_DATA_ENUM_AVAILABLE(_name, _get, _enum)
>  
> -	const struct counter_ops *ops;
> +#define COUNTER_DATA_CEILING(_read, _write) \
> +	COUNTER_DATA_UNSIGNED_LONG("ceiling", _read, _write)
>  
> -	struct counter_signal *signals;
> -	size_t num_signals;
> -	struct counter_count *counts;
> -	size_t num_counts;
> +#define COUNTER_DATA_COUNT_MODE(_read, _write) \
> +{ \
> +	.type = COUNTER_DATA_TYPE_COUNT_MODE, \
> +	.name = "count_mode", \
> +	.read = (_read), \
> +	.write = (_write), \
> +}
>  
> -	const struct counter_device_ext *ext;
> -	size_t num_ext;
> +#define COUNTER_DATA_COUNT_MODE_AVAILABLE(_read, _available) \
> +{ \
> +	.type = COUNTER_DATA_TYPE_COUNT_MODE_AVAILABLE, \
> +	.name = "count_mode_available", \
> +	.read = (_read), \
> +	.priv = &(_available), \
> +}
>  
> -	void *priv;
> -};
> +#define COUNTER_DATA_COUNT_MODE_AND_AVAILABLE(_read, _write, _available) \
> +	COUNTER_DATA_COUNT_MODE(_read, _write), \
> +	COUNTER_DATA_COUNT_MODE_AVAILABLE(_read, _available)
>  
> -int counter_register(struct counter_device *const counter);
> -void counter_unregister(struct counter_device *const counter);
> -int devm_counter_register(struct device *dev,
> -			  struct counter_device *const counter);
> -void devm_counter_unregister(struct device *dev,
> -			     struct counter_device *const counter);
> +#define COUNTER_DATA_DIRECTION(_read) \
> +{ \
> +	.type = COUNTER_DATA_TYPE_COUNT_DIRECTION, \
> +	.name = "direction", \
> +	.read = (_read), \
> +}
> +
> +#define COUNTER_DATA_ENABLE(_read, _write) \
> +	COUNTER_DATA_BOOL("enable", _read, _write)
> +
> +#define COUNTER_DATA_ERROR_NOISE_AND_AVAILABLE(_read, _available) \
> +	COUNTER_DATA_STRING("error_noise", _read, NULL), \
> +	COUNTER_DATA_STRING("error_noise_available", _available, NULL)
> +
> +#define COUNTER_DATA_FLOOR(_read, _write) \
> +	COUNTER_DATA_UNSIGNED_LONG("floor", _read, _write)
> +
> +#define COUNTER_DATA_PRESET(_read, _write) \
> +	COUNTER_DATA_UNSIGNED_LONG("preset", _read, _write)
> +
> +#define COUNTER_DATA_PRESET_ENABLE(_read, _write) \
> +	COUNTER_DATA_BOOL("preset_enable", _read, _write)
>  
>  #endif /* _COUNTER_H_ */
> diff --git a/include/linux/counter_enum.h b/include/linux/counter_enum.h
> deleted file mode 100644
> index 9f917298a88f..000000000000
> --- a/include/linux/counter_enum.h
> +++ /dev/null
> @@ -1,45 +0,0 @@
> -/* SPDX-License-Identifier: GPL-2.0 */
> -/*
> - * Counter interface enum functions
> - * Copyright (C) 2018 William Breathitt Gray
> - */
> -#ifndef _COUNTER_ENUM_H_
> -#define _COUNTER_ENUM_H_
> -
> -#include <linux/types.h>
> -
> -struct counter_device;
> -struct counter_signal;
> -struct counter_count;
> -
> -ssize_t counter_signal_enum_read(struct counter_device *counter,
> -				 struct counter_signal *signal, void *priv,
> -				 char *buf);
> -ssize_t counter_signal_enum_write(struct counter_device *counter,
> -				  struct counter_signal *signal, void *priv,
> -				  const char *buf, size_t len);
> -
> -ssize_t counter_signal_enum_available_read(struct counter_device *counter,
> -					   struct counter_signal *signal,
> -					   void *priv, char *buf);
> -
> -ssize_t counter_count_enum_read(struct counter_device *counter,
> -				struct counter_count *count, void *priv,
> -				char *buf);
> -ssize_t counter_count_enum_write(struct counter_device *counter,
> -				 struct counter_count *count, void *priv,
> -				 const char *buf, size_t len);
> -
> -ssize_t counter_count_enum_available_read(struct counter_device *counter,
> -					  struct counter_count *count,
> -					  void *priv, char *buf);
> -
> -ssize_t counter_device_enum_read(struct counter_device *counter, void *priv,
> -				 char *buf);
> -ssize_t counter_device_enum_write(struct counter_device *counter, void *priv,
> -				  const char *buf, size_t len);
> -
> -ssize_t counter_device_enum_available_read(struct counter_device *counter,
> -					   void *priv, char *buf);
> -
> -#endif /* _COUNTER_ENUM_H_ */
> diff --git a/include/uapi/linux/counter-types.h b/include/uapi/linux/counter-types.h
> new file mode 100644
> index 000000000000..757256775949
> --- /dev/null
> +++ b/include/uapi/linux/counter-types.h
> @@ -0,0 +1,67 @@
> +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
> +/*
> + * Counter interface data types
> + * Copyright (C) 2020 William Breathitt Gray
> + */
> +#ifndef _UAPI_COUNTER_TYPES_H_
> +#define _UAPI_COUNTER_TYPES_H_
> +
> +enum counter_count_direction {
> +	COUNTER_COUNT_DIRECTION_FORWARD = 0,
> +	COUNTER_COUNT_DIRECTION_BACKWARD
> +};
> +
> +enum counter_count_mode {
> +	COUNTER_COUNT_MODE_NORMAL = 0,
> +	COUNTER_COUNT_MODE_RANGE_LIMIT,
> +	COUNTER_COUNT_MODE_NON_RECYCLE,
> +	COUNTER_COUNT_MODE_MODULO_N
> +};
> +
> +enum counter_count_function {
> +	COUNTER_COUNT_FUNCTION_INCREASE = 0,
> +	COUNTER_COUNT_FUNCTION_DECREASE,
> +	COUNTER_COUNT_FUNCTION_PULSE_DIRECTION,
> +	COUNTER_COUNT_FUNCTION_QUADRATURE_X1_A,
> +	COUNTER_COUNT_FUNCTION_QUADRATURE_X1_B,
> +	COUNTER_COUNT_FUNCTION_QUADRATURE_X2_A,
> +	COUNTER_COUNT_FUNCTION_QUADRATURE_X2_B,
> +	COUNTER_COUNT_FUNCTION_QUADRATURE_X4
> +};
> +
> +enum counter_signal_value {
> +	COUNTER_SIGNAL_LOW = 0,
> +	COUNTER_SIGNAL_HIGH
> +};
> +
> +enum counter_synapse_action {
> +	COUNTER_SYNAPSE_ACTION_NONE = 0,
> +	COUNTER_SYNAPSE_ACTION_RISING_EDGE,
> +	COUNTER_SYNAPSE_ACTION_FALLING_EDGE,
> +	COUNTER_SYNAPSE_ACTION_BOTH_EDGES
> +};
> +
> +enum counter_data_type {
> +	COUNTER_DATA_TYPE_BOOL = 0,
> +	COUNTER_DATA_TYPE_UNSIGNED_LONG,
> +	COUNTER_DATA_TYPE_SIZE,
> +	COUNTER_DATA_TYPE_STRING,
> +	COUNTER_DATA_TYPE_COUNT_FUNCTION,
> +	COUNTER_DATA_TYPE_COUNT_FUNCTION_AVAILABLE,
> +	COUNTER_DATA_TYPE_SIGNAL,
> +	COUNTER_DATA_TYPE_SYNAPSE_ACTION,
> +	COUNTER_DATA_TYPE_SYNAPSE_ACTION_AVAILABLE,
> +	COUNTER_DATA_TYPE_ENUM,
> +	COUNTER_DATA_TYPE_ENUM_AVAILABLE,
> +	COUNTER_DATA_TYPE_COUNT_DIRECTION,
> +	COUNTER_DATA_TYPE_COUNT_MODE,
> +	COUNTER_DATA_TYPE_COUNT_MODE_AVAILABLE,
> +};
> +
> +enum counter_owner_type {
> +	COUNTER_OWNER_TYPE_DEVICE,
> +	COUNTER_OWNER_TYPE_SIGNAL,
> +	COUNTER_OWNER_TYPE_COUNT,
> +};
> +
> +#endif /* _UAPI_COUNTER_TYPES_H_ */

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