Message-ID: <c4fb31c20154780008473f90e5bfa4399ef2db7c.camel@rong.moe>
Date: Tue, 25 Nov 2025 04:03:34 +0800
From: Rong Zhang <i@...g.moe>
To: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
Cc: Rong Zhang <i@...g.moe>, Mark Pearson <mpearson-lenovo@...ebb.ca>, 
 "Derek J. Clark" <derekjohn.clark@...il.com>, Armin Wolf <W_Armin@....de>,
 Hans de Goede <hansg@...nel.org>,  Guenter Roeck <linux@...ck-us.net>,
 platform-driver-x86@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>, 
	linux-hwmon@...r.kernel.org
Subject: Re: [PATCH v6 3/7] platform/x86: lenovo-wmi-{capdata,other}:
 Support multiple Capability Data

Hi Ilpo,

Thanks for your review.

On Mon, 2025-11-24 at 18:30 +0200, Ilpo Järvinen wrote:
> On Sun, 23 Nov 2025, Rong Zhang wrote:
> 
> > The current implementation are heavily bound to capdata01. Rewrite it so
> > that it is suitable to utilize other Capability Data as well.
> > 
> > No functional change intended.
> > 
> > Signed-off-by: Rong Zhang <i@...g.moe>
> > Reviewed-by: Derek J. Clark <derekjohn.clark@...il.com>
> > Tested-by: Derek J. Clark <derekjohn.clark@...il.com>
> > ---
> > Changes in v6:
> > - Fix the error path of lwmi_cd_match_add_all()
> >   - IS_ERR(matchptr) => IS_ERR(*matchptr)
> > 
> > Changes in v5:
> > - Do not cast pointer to non-pointer or vice versa (thanks kernel test
> >   robot)
> > 
> > Changes in v4:
> > - Get rid of wmi_has_guid() (thanks Armin Wolf)
> >   - More changes in [PATCH v4 6/7]
> > - Prepare for [PATCH v4 6/7]
> >   - Move lwmi_cd_match*() forward
> >   - Use switch-case in lwmi_cd_remove()
> > 
> > Changes in v2:
> > - Fix function parameter 'type' not described in 'lwmi_cd_match' (thanks
> >   kernel test bot)
> > ---
> >  drivers/platform/x86/lenovo/wmi-capdata.c | 225 +++++++++++++++++-----
> >  drivers/platform/x86/lenovo/wmi-capdata.h |   7 +-
> >  drivers/platform/x86/lenovo/wmi-other.c   |  16 +-
> >  3 files changed, 189 insertions(+), 59 deletions(-)
> > 
> > diff --git a/drivers/platform/x86/lenovo/wmi-capdata.c b/drivers/platform/x86/lenovo/wmi-capdata.c
> > index c5e74b2bfeb3..e0710354278a 100644
> > --- a/drivers/platform/x86/lenovo/wmi-capdata.c
> > +++ b/drivers/platform/x86/lenovo/wmi-capdata.c
> > @@ -12,8 +12,13 @@
> >   *
> >   * Copyright (C) 2025 Derek J. Clark <derekjohn.clark@...il.com>
> >   *   - Initial implementation (formerly named lenovo-wmi-capdata01)
> > + *
> > + * Copyright (C) 2025 Rong Zhang <i@...g.moe>
> > + *   - Unified implementation
> >   */
> >  
> > +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> > +
> >  #include <linux/acpi.h>
> >  #include <linux/cleanup.h>
> >  #include <linux/component.h>
> > @@ -36,6 +41,23 @@
> >  #define ACPI_AC_CLASS "ac_adapter"
> >  #define ACPI_AC_NOTIFY_STATUS 0x80
> >  
> > +enum lwmi_cd_type {
> > +	LENOVO_CAPABILITY_DATA_01,
> > +};
> > +
> > +#define LWMI_CD_TABLE_ITEM(_type)		\
> > +	[_type] = {				\
> > +		.name = #_type,			\
> > +		.type = _type,			\
> > +	}
> > +
> > +static const struct lwmi_cd_info {
> > +	const char *name;
> > +	enum lwmi_cd_type type;
> > +} lwmi_cd_table[] = {
> > +	LWMI_CD_TABLE_ITEM(LENOVO_CAPABILITY_DATA_01),
> > +};
> > +
> >  struct lwmi_cd_priv {
> >  	struct notifier_block acpi_nb; /* ACPI events */
> >  	struct wmi_device *wdev;
> > @@ -44,15 +66,63 @@ struct lwmi_cd_priv {
> >  
> >  struct cd_list {
> >  	struct mutex list_mutex; /* list R/W mutex */
> > +	enum lwmi_cd_type type;
> >  	u8 count;
> > -	struct capdata01 data[];
> > +
> > +	union {
> > +		DECLARE_FLEX_ARRAY(struct capdata01, cd01);
> 
> Add #include

It's embarrassing that I always forget #include... Sorry for that.

Will fix this and the following missing #include. Thanks.

> > +	};
> >  };
> >  
> > +static struct wmi_driver lwmi_cd_driver;
> > +
> > +/**
> > + * lwmi_cd_match() - Match rule for the master driver.
> > + * @dev: Pointer to the capability data parent device.
> > + * @type: Pointer to capability data type (enum lwmi_cd_type *) to match.
> > + *
> > + * Return: int.
> > + */
> > +static int lwmi_cd_match(struct device *dev, void *type)
> > +{
> > +	struct lwmi_cd_priv *priv;
> > +
> > +	if (dev->driver != &lwmi_cd_driver.driver)
> > +		return false;
> > +
> > +	priv = dev_get_drvdata(dev);
> > +	return priv->list->type == *(enum lwmi_cd_type *)type;
> > +}
> > +
> > +/**
> > + * lwmi_cd_match_add_all() - Add all match rule for the master driver.
> > + * @master: Pointer to the master device.
> > + * @matchptr: Pointer to the returned component_match pointer.
> > + *
> > + * Adds all component matches to the list stored in @matchptr for the @master
> > + * device. @matchptr must be initialized to NULL.
> > + */
> > +void lwmi_cd_match_add_all(struct device *master, struct component_match **matchptr)
> > +{
> > +	int i;
> > +
> > +	if (WARN_ON(*matchptr))
> 
> Add #include
> 
> > +		return;
> > +
> > +	for (i = 0; i < ARRAY_SIZE(lwmi_cd_table); i++) {
> > +		component_match_add(master, matchptr, lwmi_cd_match,
> > +				    (void *)&lwmi_cd_table[i].type);
> 
> As the cast to void pointer necessary here? Usually pointer can be cast to 
> void * implicitly (but I'm not sure about this case type seems enum).

lwmi_cd_table is a const array, its const qualifier infects the
pointer. The cast here is to drop the const qualifier from `const enum
lwmi_cd_type *' as component_match_add() expects plain `void *'.

   warning: passing argument 4 of ‘component_match_add’ discards ‘const’
   qualifier from pointer target type [-Wdiscarded-qualifiers]
   
   note: expected ‘void *’ but argument is of type ‘const enum
   lwmi_cd_type *’

> > +		if (IS_ERR(*matchptr))
> 
> Add #include
> 
> > +			return;
> > +	}
> > +}
> > +EXPORT_SYMBOL_NS_GPL(lwmi_cd_match_add_all, "LENOVO_WMI_CD");
> > +
> >  /**
> >   * lwmi_cd_component_bind() - Bind component to master device.
> >   * @cd_dev: Pointer to the lenovo-wmi-capdata driver parent device.
> >   * @om_dev: Pointer to the lenovo-wmi-other driver parent device.
> > - * @data: cd_list object pointer used to return the capability data.
> > + * @data: lwmi_cd_binder object pointer used to return the capability data.
> >   *
> >   * On lenovo-wmi-other's master bind, provide a pointer to the local capdata
> >   * list. This is used to call lwmi_cd*_get_data to look up attribute data
> > @@ -64,9 +134,15 @@ static int lwmi_cd_component_bind(struct device *cd_dev,
> >  				  struct device *om_dev, void *data)
> >  {
> >  	struct lwmi_cd_priv *priv = dev_get_drvdata(cd_dev);
> > -	struct cd_list **cd_list = data;
> > +	struct lwmi_cd_binder *binder = data;
> >  
> > -	*cd_list = priv->list;
> > +	switch (priv->list->type) {
> > +	case LENOVO_CAPABILITY_DATA_01:
> > +		binder->cd01_list = priv->list;
> > +		break;
> > +	default:
> > +		return -EINVAL;
> > +	}
> >  
> >  	return 0;
> >  }
> > @@ -76,30 +152,33 @@ static const struct component_ops lwmi_cd_component_ops = {
> >  };
> >  
> >  /**
> > - * lwmi_cd01_get_data - Get the data of the specified attribute
> > + * lwmi_cd*_get_data - Get the data of the specified attribute
> >   * @list: The lenovo-wmi-capdata pointer to its cd_list struct.
> >   * @attribute_id: The capdata attribute ID to be found.
> > - * @output: Pointer to a capdata01 struct to return the data.
> > + * @output: Pointer to a capdata* struct to return the data.
> >   *
> > - * Retrieves the capability data 01 struct pointer for the given
> > - * attribute for its specified thermal mode.
> > + * Retrieves the capability data struct pointer for the given
> > + * attribute.
> >   *
> >   * Return: 0 on success, or -EINVAL.
> >   */
> > -int lwmi_cd01_get_data(struct cd_list *list, u32 attribute_id, struct capdata01 *output)
> > -{
> > -	u8 idx;
> > -
> > -	guard(mutex)(&list->list_mutex);
> > -	for (idx = 0; idx < list->count; idx++) {
> > -		if (list->data[idx].id != attribute_id)
> > -			continue;
> > -		memcpy(output, &list->data[idx], sizeof(list->data[idx]));
> > -		return 0;
> > +#define DEF_LWMI_CDXX_GET_DATA(_cdxx, _cd_type, _output_t)					\
> > +	int lwmi_##_cdxx##_get_data(struct cd_list *list, u32 attribute_id, _output_t *output)	\
> > +	{											\
> > +		u8 idx;										\
> 
> Please follow the normal conversions, so add an empty line here (with the
> backslash contination, obviusly).

Will fix this and the following formatting issues (empty line, comma,
{0} => {}). Thanks.

> > +		if (WARN_ON(list->type != _cd_type))						\
> > +			return -EINVAL;								\
> 
> Empty line here too to help readability?
> 
> > +		guard(mutex)(&list->list_mutex);						\
> > +		for (idx = 0; idx < list->count; idx++) {					\
> > +			if (list->_cdxx[idx].id != attribute_id)				\
> > +				continue;							\
> > +			memcpy(output, &list->_cdxx[idx], sizeof(list->_cdxx[idx]));		\
> > +			return 0;								\
> > +		}										\
> > +		return -EINVAL;									\
> >  	}
> >  
> > -	return -EINVAL;
> > -}
> > +DEF_LWMI_CDXX_GET_DATA(cd01, LENOVO_CAPABILITY_DATA_01, struct capdata01);
> >  EXPORT_SYMBOL_NS_GPL(lwmi_cd01_get_data, "LENOVO_WMI_CD");
> >  
> >  /**
> > @@ -112,10 +191,21 @@ EXPORT_SYMBOL_NS_GPL(lwmi_cd01_get_data, "LENOVO_WMI_CD");
> >   */
> >  static int lwmi_cd_cache(struct lwmi_cd_priv *priv)
> >  {
> > +	size_t size;
> >  	int idx;
> > +	void *p;
> > +
> > +	switch (priv->list->type) {
> > +	case LENOVO_CAPABILITY_DATA_01:
> > +		p = &priv->list->cd01[0];
> > +		size = sizeof(priv->list->cd01[0]);
> > +		break;
> > +	default:
> > +		return -EINVAL;
> > +	}
> >  
> >  	guard(mutex)(&priv->list->list_mutex);
> > -	for (idx = 0; idx < priv->list->count; idx++) {
> > +	for (idx = 0; idx < priv->list->count; idx++, p += size) {
> >  		union acpi_object *ret_obj __free(kfree) = NULL;
> >  
> >  		ret_obj = wmidev_block_query(priv->wdev, idx);
> > @@ -123,11 +213,10 @@ static int lwmi_cd_cache(struct lwmi_cd_priv *priv)
> >  			return -ENODEV;
> >  
> >  		if (ret_obj->type != ACPI_TYPE_BUFFER ||
> > -		    ret_obj->buffer.length < sizeof(priv->list->data[idx]))
> > +		    ret_obj->buffer.length < size)
> >  			continue;
> >  
> > -		memcpy(&priv->list->data[idx], ret_obj->buffer.pointer,
> > -		       ret_obj->buffer.length);
> > +		memcpy(p, ret_obj->buffer.pointer, size);
> >  	}
> >  
> >  	return 0;
> > @@ -136,20 +225,28 @@ static int lwmi_cd_cache(struct lwmi_cd_priv *priv)
> >  /**
> >   * lwmi_cd_alloc() - Allocate a cd_list struct in drvdata
> >   * @priv: lenovo-wmi-capdata driver data.
> > + * @type: The type of capability data.
> >   *
> >   * Allocate a cd_list struct large enough to contain data from all WMI data
> >   * blocks provided by the interface.
> >   *
> >   * Return: 0 on success, or an error.
> >   */
> > -static int lwmi_cd_alloc(struct lwmi_cd_priv *priv)
> > +static int lwmi_cd_alloc(struct lwmi_cd_priv *priv, enum lwmi_cd_type type)
> >  {
> >  	struct cd_list *list;
> >  	size_t list_size;
> >  	int count, ret;
> >  
> >  	count = wmidev_instance_count(priv->wdev);
> > -	list_size = struct_size(list, data, count);
> > +
> > +	switch (type) {
> > +	case LENOVO_CAPABILITY_DATA_01:
> > +		list_size = struct_size(list, cd01, count);
> > +		break;
> > +	default:
> > +		return -EINVAL;
> > +	}
> >  
> >  	list = devm_kzalloc(&priv->wdev->dev, list_size, GFP_KERNEL);
> >  	if (!list)
> > @@ -159,6 +256,7 @@ static int lwmi_cd_alloc(struct lwmi_cd_priv *priv)
> >  	if (ret)
> >  		return ret;
> >  
> > +	list->type = type;
> >  	list->count = count;
> >  	priv->list = list;
> >  
> > @@ -168,6 +266,7 @@ static int lwmi_cd_alloc(struct lwmi_cd_priv *priv)
> >  /**
> >   * lwmi_cd_setup() - Cache all WMI data block information
> >   * @priv: lenovo-wmi-capdata driver data.
> > + * @type: The type of capability data.
> >   *
> >   * Allocate a cd_list struct large enough to contain data from all WMI data
> >   * blocks provided by the interface. Then loop through each data block and
> > @@ -175,11 +274,11 @@ static int lwmi_cd_alloc(struct lwmi_cd_priv *priv)
> >   *
> >   * Return: 0 on success, or an error code.
> >   */
> > -static int lwmi_cd_setup(struct lwmi_cd_priv *priv)
> > +static int lwmi_cd_setup(struct lwmi_cd_priv *priv, enum lwmi_cd_type type)
> >  {
> >  	int ret;
> >  
> > -	ret = lwmi_cd_alloc(priv);
> > +	ret = lwmi_cd_alloc(priv, type);
> >  	if (ret)
> >  		return ret;
> >  
> > @@ -235,9 +334,13 @@ static void lwmi_cd01_unregister(void *data)
> >  
> >  static int lwmi_cd_probe(struct wmi_device *wdev, const void *context)
> >  {
> > +	const struct lwmi_cd_info *info = context;
> >  	struct lwmi_cd_priv *priv;
> >  	int ret;
> >  
> > +	if (!info)
> > +		return -EINVAL;
> > +
> >  	priv = devm_kzalloc(&wdev->dev, sizeof(*priv), GFP_KERNEL);
> >  	if (!priv)
> >  		return -ENOMEM;
> > @@ -245,30 +348,58 @@ static int lwmi_cd_probe(struct wmi_device *wdev, const void *context)
> >  	priv->wdev = wdev;
> >  	dev_set_drvdata(&wdev->dev, priv);
> >  
> > -	ret = lwmi_cd_setup(priv);
> > +	ret = lwmi_cd_setup(priv, info->type);
> >  	if (ret)
> > -		return ret;
> > +		goto out;
> >  
> > -	priv->acpi_nb.notifier_call = lwmi_cd01_notifier_call;
> > +	switch (info->type) {
> > +	case LENOVO_CAPABILITY_DATA_01:
> > +		priv->acpi_nb.notifier_call = lwmi_cd01_notifier_call;
> >  
> > -	ret = register_acpi_notifier(&priv->acpi_nb);
> > -	if (ret)
> > -		return ret;
> > +		ret = register_acpi_notifier(&priv->acpi_nb);
> > +		if (ret)
> > +			goto out;
> >  
> > -	ret = devm_add_action_or_reset(&wdev->dev, lwmi_cd01_unregister, &priv->acpi_nb);
> > -	if (ret)
> > -		return ret;
> > +		ret = devm_add_action_or_reset(&wdev->dev, lwmi_cd01_unregister,
> > +					       &priv->acpi_nb);
> > +		if (ret)
> > +			goto out;
> >  
> > -	return component_add(&wdev->dev, &lwmi_cd_component_ops);
> > +		ret = component_add(&wdev->dev, &lwmi_cd_component_ops);
> > +		goto out;
> > +	default:
> > +		return -EINVAL;
> > +	}
> > +out:
> > +	if (ret) {
> > +		dev_err(&wdev->dev, "failed to register %s: %d\n",
> 
> Include?
> 
> > +			info->name, ret);
> > +	} else {
> > +		dev_info(&wdev->dev, "registered %s with %u items\n",
> > +			 info->name, priv->list->count);
> 
> Success path should be quiet.

Will turn it into dev_dbg(). Thanks.

Thanks,
Rong

> > +	}
> > +	return ret;
> >  }
> >  
> >  static void lwmi_cd_remove(struct wmi_device *wdev)
> >  {
> > -	component_del(&wdev->dev, &lwmi_cd_component_ops);
> > +	struct lwmi_cd_priv *priv = dev_get_drvdata(&wdev->dev);
> > +
> > +	switch (priv->list->type) {
> > +	case LENOVO_CAPABILITY_DATA_01:
> > +		component_del(&wdev->dev, &lwmi_cd_component_ops);
> > +		break;
> > +	default:
> > +		WARN_ON(1);
> > +	}
> >  }
> >  
> > +#define LWMI_CD_WDEV_ID(_type)				\
> > +	.guid_string = _type##_GUID,			\
> > +	.context = &lwmi_cd_table[_type]
> 
> Add comma.
> 
> > +
> >  static const struct wmi_device_id lwmi_cd_id_table[] = {
> > -	{ LENOVO_CAPABILITY_DATA_01_GUID, NULL },
> > +	{ LWMI_CD_WDEV_ID(LENOVO_CAPABILITY_DATA_01) },
> >  	{}
> >  };
> >  
> > @@ -283,22 +414,10 @@ static struct wmi_driver lwmi_cd_driver = {
> >  	.no_singleton = true,
> >  };
> >  
> > -/**
> > - * lwmi_cd01_match() - Match rule for the master driver.
> > - * @dev: Pointer to the capability data 01 parent device.
> > - * @data: Unused void pointer for passing match criteria.
> > - *
> > - * Return: int.
> > - */
> > -int lwmi_cd01_match(struct device *dev, void *data)
> > -{
> > -	return dev->driver == &lwmi_cd_driver.driver;
> > -}
> > -EXPORT_SYMBOL_NS_GPL(lwmi_cd01_match, "LENOVO_WMI_CD");
> > -
> >  module_wmi_driver(lwmi_cd_driver);
> >  
> >  MODULE_DEVICE_TABLE(wmi, lwmi_cd_id_table);
> >  MODULE_AUTHOR("Derek J. Clark <derekjohn.clark@...il.com>");
> > +MODULE_AUTHOR("Rong Zhang <i@...g.moe>");
> >  MODULE_DESCRIPTION("Lenovo Capability Data WMI Driver");
> >  MODULE_LICENSE("GPL");
> > diff --git a/drivers/platform/x86/lenovo/wmi-capdata.h b/drivers/platform/x86/lenovo/wmi-capdata.h
> > index 2a4746e38ad4..d326f9d2d165 100644
> > --- a/drivers/platform/x86/lenovo/wmi-capdata.h
> > +++ b/drivers/platform/x86/lenovo/wmi-capdata.h
> > @@ -7,6 +7,7 @@
> >  
> >  #include <linux/types.h>
> >  
> > +struct component_match;
> >  struct device;
> >  struct cd_list;
> >  
> > @@ -19,7 +20,11 @@ struct capdata01 {
> >  	u32 max_value;
> >  };
> >  
> > +struct lwmi_cd_binder {
> > +	struct cd_list *cd01_list;
> > +};
> > +
> > +void lwmi_cd_match_add_all(struct device *master, struct component_match **matchptr);
> >  int lwmi_cd01_get_data(struct cd_list *list, u32 attribute_id, struct capdata01 *output);
> > -int lwmi_cd01_match(struct device *dev, void *data);
> >  
> >  #endif /* !_LENOVO_WMI_CAPDATA_H_ */
> > diff --git a/drivers/platform/x86/lenovo/wmi-other.c b/drivers/platform/x86/lenovo/wmi-other.c
> > index c6dc1b4cff84..f2e1e34d58a9 100644
> > --- a/drivers/platform/x86/lenovo/wmi-other.c
> > +++ b/drivers/platform/x86/lenovo/wmi-other.c
> > @@ -579,14 +579,14 @@ static void lwmi_om_fw_attr_remove(struct lwmi_om_priv *priv)
> >  static int lwmi_om_master_bind(struct device *dev)
> >  {
> >  	struct lwmi_om_priv *priv = dev_get_drvdata(dev);
> > -	struct cd_list *tmp_list;
> > +	struct lwmi_cd_binder binder = { 0 };
> 
> = {} is enough to initialize to default values.
> 
> >  	int ret;
> >  
> > -	ret = component_bind_all(dev, &tmp_list);
> > +	ret = component_bind_all(dev, &binder);
> >  	if (ret)
> >  		return ret;
> >  
> > -	priv->cd01_list = tmp_list;
> > +	priv->cd01_list = binder.cd01_list;
> >  	if (!priv->cd01_list)
> >  		return -ENODEV;
> >  
> > @@ -623,10 +623,13 @@ static int lwmi_other_probe(struct wmi_device *wdev, const void *context)
> >  	if (!priv)
> >  		return -ENOMEM;
> >  
> > +	/* Sentinel for on-demand ida_free(). */
> > +	priv->ida_id = -EIDRM;
> > +
> >  	priv->wdev = wdev;
> >  	dev_set_drvdata(&wdev->dev, priv);
> >  
> > -	component_match_add(&wdev->dev, &master_match, lwmi_cd01_match, NULL);
> > +	lwmi_cd_match_add_all(&wdev->dev, &master_match);
> >  	if (IS_ERR(master_match))
> >  		return PTR_ERR(master_match);
> >  
> > @@ -639,7 +642,10 @@ static void lwmi_other_remove(struct wmi_device *wdev)
> >  	struct lwmi_om_priv *priv = dev_get_drvdata(&wdev->dev);
> >  
> >  	component_master_del(&wdev->dev, &lwmi_om_master_ops);
> > -	ida_free(&lwmi_om_ida, priv->ida_id);
> > +
> > +	/* No IDA to free if the driver is never bound to its components. */
> > +	if (priv->ida_id >= 0)
> > +		ida_free(&lwmi_om_ida, priv->ida_id);
> >  }
> >  
> >  static const struct wmi_device_id lwmi_other_id_table[] = {
> > 

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