Message-ID: <f3956fab-04b5-c86d-2625-4e8bdf81b697@linux.intel.com>
Date: Mon, 24 Nov 2025 18:30:46 +0200 (EET)
From: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
To: Rong Zhang <i@...g.moe>
cc: 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

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

> +	};
>  };
>  
> +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).

> +		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).

> +		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.

> +	}
> +	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[] = {
> 

-- 
 i.

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