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Message-ID: <YS452wJ+IHs9R0FC@shinobu>
Date: Tue, 31 Aug 2021 23:16:59 +0900
From: William Breathitt Gray <vilhelm.gray@...il.com>
To: Fabrice Gasnier <fabrice.gasnier@...s.st.com>
Cc: jic23@...nel.org, kamel.bouhara@...tlin.com, gwendal@...omium.org,
david@...hnology.com, linux-iio@...r.kernel.org,
patrick.havelange@...ensium.com, alexandre.belloni@...tlin.com,
mcoquelin.stm32@...il.com, linux-kernel@...r.kernel.org,
o.rempel@...gutronix.de, jarkko.nikula@...ux.intel.com,
Dan Carpenter <dan.carpenter@...cle.com>,
kernel@...gutronix.de, fabrice.gasnier@...com,
syednwaris@...il.com, linux-stm32@...md-mailman.stormreply.com,
linux-arm-kernel@...ts.infradead.org, alexandre.torgue@...com
Subject: Re: [Linux-stm32] [PATCH v16 03/14] counter: Internalize sysfs
interface code
On Tue, Aug 31, 2021 at 03:44:04PM +0200, Fabrice Gasnier wrote:
> On 8/27/21 5:47 AM, William Breathitt Gray 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.
> >
> > 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. u8, u64, etc.) and the shared counter
> > module handles the translation between the sysfs interface and the
> > device drivers. This guarantees a standard userspace interface for all
> > counter drivers, and helps generalize the Generic Counter driver ABI in
> > order to support the Generic Counter chrdev interface (introduced in a
> > subsequent patch) without significant changes to the existing counter
> > drivers.
> >
> > Note, 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_comp structure forms the basis for Counter
> > extensions.
> >
> > 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 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 called, and sysfs
> > I/O is handled before or after the driver read/write function is called.
> >
> > Cc: Jarkko Nikula <jarkko.nikula@...ux.intel.com>
> > Cc: Patrick Havelange <patrick.havelange@...ensium.com>
> > Cc: Kamel Bouhara <kamel.bouhara@...tlin.com>
> > Cc: Fabrice Gasnier <fabrice.gasnier@...com>
> > Cc: Maxime Coquelin <mcoquelin.stm32@...il.com>
> > Cc: Alexandre Torgue <alexandre.torgue@...com>
> > Cc: Dan Carpenter <dan.carpenter@...cle.com>
> > Acked-by: Syed Nayyar Waris <syednwaris@...il.com>
> > Reviewed-by: David Lechner <david@...hnology.com>
> > Tested-by: David Lechner <david@...hnology.com>
> > Signed-off-by: William Breathitt Gray <vilhelm.gray@...il.com>
> > ---
> > MAINTAINERS | 1 -
> > drivers/counter/104-quad-8.c | 449 +++----
> > drivers/counter/Makefile | 1 +
> > drivers/counter/counter-core.c | 142 +++
> > drivers/counter/counter-sysfs.c | 849 +++++++++++++
> > drivers/counter/counter-sysfs.h | 13 +
> > drivers/counter/counter.c | 1496 -----------------------
> > drivers/counter/ftm-quaddec.c | 60 +-
> > drivers/counter/intel-qep.c | 144 +--
> > drivers/counter/interrupt-cnt.c | 62 +-
> > drivers/counter/microchip-tcb-capture.c | 91 +-
> > drivers/counter/stm32-lptimer-cnt.c | 212 ++--
> > drivers/counter/stm32-timer-cnt.c | 179 ++-
> > drivers/counter/ti-eqep.c | 180 +--
> > include/linux/counter.h | 658 +++++-----
> > include/linux/counter_enum.h | 45 -
> > 16 files changed, 1949 insertions(+), 2633 deletions(-)
> > create mode 100644 drivers/counter/counter-core.c
> > 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
> >
>
> Hi William,
>
> For the STM32 drivers, you can add my:
> Reviewed-by: Fabrice Gasnier <fabrice.gasnier@...s.st.com>
>
> Thanks,
> Fabrice
Hello Fabrice,
I noticed the stm32-lptimer-cnt.c function_write() and action_write()
callbacks do not appear to write the desired function/action
configuration to the device. Would you check whether the device actually
supports this functionality or if these callbacks should be removed from
this driver.
Thanks,
William Breathitt Gray
> > diff --git a/drivers/counter/stm32-lptimer-cnt.c b/drivers/counter/stm32-lptimer-cnt.c
> > index 7367f46c6f91..5168833b1fdf 100644
> > --- a/drivers/counter/stm32-lptimer-cnt.c
> > +++ b/drivers/counter/stm32-lptimer-cnt.c
> > @@ -170,28 +154,28 @@ static int stm32_lptim_cnt_read(struct counter_device *counter,
> > return 0;
> > }
> >
> > -static int stm32_lptim_cnt_function_get(struct counter_device *counter,
> > - struct counter_count *count,
> > - size_t *function)
> > +static int stm32_lptim_cnt_function_read(struct counter_device *counter,
> > + struct counter_count *count,
> > + enum counter_function *function)
> > {
> > struct stm32_lptim_cnt *const priv = counter->priv;
> >
> > if (!priv->quadrature_mode) {
> > - *function = STM32_LPTIM_COUNTER_INCREASE;
> > + *function = COUNTER_FUNCTION_INCREASE;
> > return 0;
> > }
> >
> > - if (priv->polarity == STM32_LPTIM_SYNAPSE_ACTION_BOTH_EDGES) {
> > - *function = STM32_LPTIM_ENCODER_BOTH_EDGE;
> > + if (priv->polarity == STM32_LPTIM_CKPOL_BOTH_EDGES) {
> > + *function = COUNTER_FUNCTION_QUADRATURE_X4;
> > return 0;
> > }
> >
> > return -EINVAL;
> > }
> >
> > -static int stm32_lptim_cnt_function_set(struct counter_device *counter,
> > - struct counter_count *count,
> > - size_t function)
> > +static int stm32_lptim_cnt_function_write(struct counter_device *counter,
> > + struct counter_count *count,
> > + enum counter_function function)
> > {
> > struct stm32_lptim_cnt *const priv = counter->priv;
> >
> > @@ -199,12 +183,12 @@ static int stm32_lptim_cnt_function_set(struct counter_device *counter,
> > return -EBUSY;
> >
> > switch (function) {
> > - case STM32_LPTIM_COUNTER_INCREASE:
> > + case COUNTER_FUNCTION_INCREASE:
> > priv->quadrature_mode = 0;
> > return 0;
> > - case STM32_LPTIM_ENCODER_BOTH_EDGE:
> > + case COUNTER_FUNCTION_QUADRATURE_X4:
> > priv->quadrature_mode = 1;
> > - priv->polarity = STM32_LPTIM_SYNAPSE_ACTION_BOTH_EDGES;
> > + priv->polarity = STM32_LPTIM_CKPOL_BOTH_EDGES;
> > return 0;
> > default:
> > /* should never reach this path */
> > @@ -333,43 +316,48 @@ static int stm32_lptim_cnt_action_get(struct counter_device *counter,
> > }
> > }
> >
> > -static int stm32_lptim_cnt_action_set(struct counter_device *counter,
> > - struct counter_count *count,
> > - struct counter_synapse *synapse,
> > - size_t action)
> > +static int stm32_lptim_cnt_action_write(struct counter_device *counter,
> > + struct counter_count *count,
> > + struct counter_synapse *synapse,
> > + enum counter_synapse_action action)
> > {
> > struct stm32_lptim_cnt *const priv = counter->priv;
> > - size_t function;
> > + enum counter_function function;
> > int err;
> >
> > if (stm32_lptim_is_enabled(priv))
> > return -EBUSY;
> >
> > - err = stm32_lptim_cnt_function_get(counter, count, &function);
> > + err = stm32_lptim_cnt_function_read(counter, count, &function);
> > if (err)
> > return err;
> >
> > /* 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 (function != COUNTER_FUNCTION_INCREASE
> > + || synapse->signal->id != count->synapses[0].signal->id)
> > + return -EINVAL;
> >
> > - return -EINVAL;
> > + switch (action) {
> > + case COUNTER_SYNAPSE_ACTION_RISING_EDGE:
> > + priv->polarity = STM32_LPTIM_CKPOL_RISING_EDGE;
> > + return 0;
> > + case COUNTER_SYNAPSE_ACTION_FALLING_EDGE:
> > + priv->polarity = STM32_LPTIM_CKPOL_FALLING_EDGE;
> > + return 0;
> > + case COUNTER_SYNAPSE_ACTION_BOTH_EDGES:
> > + priv->polarity = STM32_LPTIM_CKPOL_BOTH_EDGES;
> > + return 0;
> > + default:
> > + return -EINVAL;
> > + }
> > }
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