Message-ID: <B16C2588-E3C4-44FE-A92E-DFF9D18967AA@gmail.com>
Date: Sat, 03 May 2025 20:05:46 -0700
From: "Derek J. Clark" <derekjohn.clark@...il.com>
To: Armin Wolf <W_Armin@....de>, Hans de Goede <hdegoede@...hat.com>,
 Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
CC: Jonathan Corbet <corbet@....net>, Mario Limonciello <superm1@...nel.org>,
 Luke Jones <luke@...nes.dev>, Xino Ni <nijs1@...ovo.com>,
 Zhixin Zhang <zhangzx36@...ovo.com>, Mia Shao <shaohz1@...ovo.com>,
 Mark Pearson <mpearson-lenovo@...ebb.ca>,
 "Pierre-Loup A . Griffais" <pgriffais@...vesoftware.com>,
 "Cody T . -H . Chiu" <codyit@...il.com>, John Martens <johnfanv2@...il.com>,
 platform-driver-x86@...r.kernel.org, linux-doc@...r.kernel.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH v7 4/6] platform/x86: Add Lenovo Capability Data 01 WMI Driver



On May 3, 2025 7:18:43 PM PDT, Armin Wolf <W_Armin@....de> wrote:
>Am 03.05.25 um 02:01 schrieb Derek J. Clark:
>
>> Adds lenovo-wmi-capdata01 driver which provides the
>> LENOVO_CAPABILITY_DATA_01 WMI data block that comes on "Other Mode"
>> enabled hardware. Provides an interface for querying if a given
>> attribute is supported by the hardware, as well as its default_value,
>> max_value, min_value, and step increment.
>> 
>> Reviewed-by: Armin Wolf <W_Armin@....de>
>> Signed-off-by: Derek J. Clark <derekjohn.clark@...il.com>
>> --
>> v7:
>>   - Do memcpy instead of returning pointer in lwmi_cd01_get_data.
>>   - Put list mutex inside lwmi_cd01_priv struct.
>>   - Unregister from acpi events on dev remove.
>>   - Fix typos.
>> v6:
>>   - Recache capabiltiy data on ACPI AC events to ensure accutare
>>     max_value.
>>   - Fix typos and rewordings from v5 review.
>> v5:
>>   - Return to cache at device initialization. On component bind, pass a
>>     pointer to lenovo-wmi-other.
>>   - Fixes from v4 review.
>> v4:
>>   - Make driver data a private struct, remove references from Other Mode
>>     driver.
>>   - Don't cache data at device initialization. Instead, on component bind,
>>     cache the data on a member variable of the Other Mode driver data
>>     passed as a void pointer.
>>   - Add header file for capdata01 structs.
>>   - Add new struct to pass capdata01 array data and array length to Other
>>     Mode.
>> v3:
>> - Add as component to lenovo-wmi-other driver.
>> v2:
>> - Use devm_kmalloc to ensure driver can be instanced, remove global
>>    reference.
>> - Ensure reverse Christmas tree for all variable declarations.
>> - Remove extra whitespace.
>> - Use guard(mutex) in all mutex instances, global mutex.
>> - Use pr_fmt instead of adding the driver name to each pr_err.
>> - Remove noisy pr_info usage.
>> - Rename capdata_wmi to lenovo_wmi_cd01_priv and cd01_wmi to priv.
>> - Use list to get the lenovo_wmi_cd01_priv instance in
>>    lenovo_wmi_capdata01_get as none of the data provided by the macros
>>    that will use it can pass a member of the struct for use in
>>    container_of.
>> ---
>>   MAINTAINERS                                 |   1 +
>>   drivers/platform/x86/Kconfig                |   4 +
>>   drivers/platform/x86/Makefile               |   1 +
>>   drivers/platform/x86/lenovo-wmi-capdata01.c | 301 ++++++++++++++++++++
>>   drivers/platform/x86/lenovo-wmi-capdata01.h |  25 ++
>>   5 files changed, 332 insertions(+)
>>   create mode 100644 drivers/platform/x86/lenovo-wmi-capdata01.c
>>   create mode 100644 drivers/platform/x86/lenovo-wmi-capdata01.h
>> 
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index 2b4b06e81192..1b22e41cc730 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -13164,6 +13164,7 @@ L:	platform-driver-x86@...r.kernel.org
>>   S:	Maintained
>>   F:	Documentation/wmi/devices/lenovo-wmi-gamezone.rst
>>   F:	Documentation/wmi/devices/lenovo-wmi-other.rst
>> +F:	drivers/platform/x86/lenovo-wmi-capdata01.*
>>   F:	drivers/platform/x86/lenovo-wmi-events.*
>>   F:	drivers/platform/x86/lenovo-wmi-helpers.*
>>   diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
>> index 13b8f4ac5dc5..64663667f0cb 100644
>> --- a/drivers/platform/x86/Kconfig
>> +++ b/drivers/platform/x86/Kconfig
>> @@ -467,6 +467,10 @@ config LENOVO_WMI_HELPERS
>>   	tristate
>>   	depends on ACPI_WMI
>>   +config LENOVO_WMI_DATA01
>> +	tristate
>> +	depends on ACPI_WMI
>> +
>>   config IDEAPAD_LAPTOP
>>   	tristate "Lenovo IdeaPad Laptop Extras"
>>   	depends on ACPI
>> diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
>> index fc039839286a..7a35c77221b7 100644
>> --- a/drivers/platform/x86/Makefile
>> +++ b/drivers/platform/x86/Makefile
>> @@ -69,6 +69,7 @@ obj-$(CONFIG_THINKPAD_LMI)	+= think-lmi.o
>>   obj-$(CONFIG_YOGABOOK)		+= lenovo-yogabook.o
>>   obj-$(CONFIG_YT2_1380)		+= lenovo-yoga-tab2-pro-1380-fastcharger.o
>>   obj-$(CONFIG_LENOVO_WMI_CAMERA)	+= lenovo-wmi-camera.o
>> +obj-$(CONFIG_LENOVO_WMI_DATA01)	+= lenovo-wmi-capdata01.o
>>   obj-$(CONFIG_LENOVO_WMI_EVENTS)	+= lenovo-wmi-events.o
>>   obj-$(CONFIG_LENOVO_WMI_HELPERS)	+= lenovo-wmi-helpers.o
>>   diff --git a/drivers/platform/x86/lenovo-wmi-capdata01.c b/drivers/platform/x86/lenovo-wmi-capdata01.c
>> new file mode 100644
>> index 000000000000..419b51f7f7c3
>> --- /dev/null
>> +++ b/drivers/platform/x86/lenovo-wmi-capdata01.c
>> @@ -0,0 +1,301 @@
>> +// SPDX-License-Identifier: GPL-2.0-or-later
>> +/*
>> + * Lenovo Capability Data 01 WMI Data Block driver.
>> + *
>> + * Lenovo Capability Data 01 provides information on tunable attributes used by
>> + * the "Other Mode" WMI interface. The data includes if the attribute is
>> + * supported by the hardware, the default_value, max_value, min_value, and step
>> + * increment. Each attibute has multiple pages, one for each of the thermal
>> + * modes managed by the Gamezone interface.
>> + *
>> + * Copyright (C) 2025 Derek J. Clark <derekjohn.clark@...il.com>
>> + */
>> +
>> +#include "linux/printk.h"
>> +#include <linux/acpi.h>
>> +#include <linux/cleanup.h>
>> +#include <linux/component.h>
>> +#include <linux/container_of.h>
>> +#include <linux/device.h>
>> +#include <linux/export.h>
>> +#include <linux/gfp_types.h>
>> +#include <linux/module.h>
>> +#include <linux/mutex.h>
>> +#include <linux/mutex_types.h>
>> +#include <linux/notifier.h>
>> +#include <linux/overflow.h>
>> +#include <linux/types.h>
>> +#include <linux/wmi.h>
>> +
>> +#include "lenovo-wmi-capdata01.h"
>> +
>> +#define LENOVO_CAPABILITY_DATA_01_GUID "7A8F5407-CB67-4D6E-B547-39B3BE018154"
>> +
>> +#define ACPI_AC_CLASS "ac_adapter"
>> +#define ACPI_AC_NOTIFY_STATUS 0x80
>> +
>> +struct lwmi_cd01_priv {
>> +	struct notifier_block acpi_nb; /* ACPI events */
>> +	struct wmi_device *wdev;
>> +	struct cd01_list *list;
>> +};
>> +
>> +struct cd01_list {
>> +	struct mutex list_mutex; /* list R/W mutex */
>> +	u8 count;
>> +	struct capdata01 data[];
>> +};
>> +
>> +/**
>> + * lwmi_cd01_component_bind() - Bind component to master device.
>> + * @cd01_dev: Pointer to the lenovo-wmi-capdata01 driver parent device.
>> + * @om_dev: Pointer to the lenovo-wmi-other driver parent device.
>> + * @data: capdata01_list object pointer used to return the capability data.
>> + *
>> + * On lenovo-wmi-other's master bind, provide a pointer to the local capdata01
>> + * list. This is used to call lwmi_cd01_get_data to look up attribute data
>> + * from the lenovo-wmi-other driver.
>> + *
>> +:* Return: 0 on success, or an error code.
>> + */
>> +static int lwmi_cd01_component_bind(struct device *cd01_dev,
>> +				    struct device *om_dev, void *data)
>> +{
>> +	struct lwmi_cd01_priv *priv = dev_get_drvdata(cd01_dev);
>> +	struct cd01_list **cd01_list = data;
>> +
>> +	if (!priv->list)
>> +		return -ENODEV;
>
>Hi,
>
>can priv->list ever be NULL after initialization?
>

I don't think so. If the malloc fails it should bail before it binds, and ac events just update the data. I'll drop the check. Thanks.

>> +
>> +	*cd01_list = priv->list;
>> +
>> +	return 0;
>> +}
>> +
>> +static const struct component_ops lwmi_cd01_component_ops = {
>> +	.bind = lwmi_cd01_component_bind,
>> +};
>> +
>> +/**
>> + * lwmi_cd01_get_data - Get the data of the specified attribute
>> + * @dev: The lenovo-wmi-capdata01 parent device.
>> + * @tunable_attr: The attribute to be found.
>> + * @output: Pointer to a capdata01 struct to return the data.
>> + *
>> + * Retrieves the capability data 01 struct pointer for the given
>> + * attribute for its specified thermal mode.
>> + *
>> + * Return: 0 on success, or -EINVAL.
>> + */
>> +int lwmi_cd01_get_data(struct cd01_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;
>> +	};
>> +
>> +	return -EINVAL;
>> +}
>> +EXPORT_SYMBOL_NS_GPL(lwmi_cd01_get_data, "LENOVO_WMI_CD01");
>> +
>> +/**
>> + * lwmi_cd01_setup() - Cache all WMI data block information
>> + * @priv: lenovo-wmi-capdata01 driver data.
>> + *
>> + * Loop through each WMI data block and cache the data.
>> + *
>> + * Return: 0 on success, or an error.
>> + */
>> +static int lwmi_cd01_cache(struct lwmi_cd01_priv *priv)
>> +{
>> +	int idx;
>> +
>> +	guard(mutex)(&priv->list->list_mutex);
>> +	for (idx = 0; idx < priv->list->count; idx++) {
>> +		union acpi_object *ret_obj __free(kfree) = NULL;
>> +
>> +		ret_obj = wmidev_block_query(priv->wdev, idx);
>> +		if (!ret_obj)
>> +			return -ENODEV;
>> +
>> +		if (ret_obj->type != ACPI_TYPE_BUFFER ||
>> +		    ret_obj->buffer.length < sizeof(priv->list->data[idx]))
>> +			continue;
>> +
>> +		memcpy(&priv->list->data[idx], ret_obj->buffer.pointer,
>> +		       ret_obj->buffer.length);
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +/**
>> + * lwmi_cd01_alloc() - Allocate a cd01_list struct in drvdata
>> + * @priv: lenovo-wmi-capdata01 driver data.
>> + *
>> + * Allocate a cd01_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_cd01_alloc(struct lwmi_cd01_priv *priv)
>> +{
>> +	struct cd01_list *list;
>> +	size_t list_size;
>> +	int count;
>> +
>> +	count = wmidev_instance_count(priv->wdev);
>> +	list_size = struct_size(list, data, count);
>> +
>> +	list = devm_kzalloc(&priv->wdev->dev, list_size, GFP_KERNEL);
>> +	if (!list)
>> +		return -ENOMEM;
>> +
>> +	mutex_init(&list->list_mutex);
>
>Please use devm_mutex_init() here.
>
>> +	list->count = count;
>> +	priv->list = list;
>> +
>> +	return 0;
>> +}
>> +
>> +/**
>> + * lwmi_cd01_setup() - Cache all WMI data block information
>> + * @priv: lenovo-wmi-capdata01 driver data.
>> + *
>> + * Allocate a cd01_list struct large enough to contain data from all WMI data
>> + * blocks provided by the interface. Then loop through each data block and
>> + * cache the data.
>> + *
>> + * Return: 0 on success, or an error code.
>> + */
>> +static int lwmi_cd01_setup(struct lwmi_cd01_priv *priv)
>> +{
>> +	int ret;
>> +
>> +	ret = lwmi_cd01_alloc(priv);
>> +	if (ret)
>> +		return ret;
>> +
>> +	return lwmi_cd01_cache(priv);
>> +}
>> +
>> +/**
>> + * lwmi_cd01_notifier_call() - Call method for lenovo-wmi-capdata01 driver notifier.
>> + * block call chain.
>> + * @nb: The notifier_block registered to lenovo-wmi-events driver.
>> + * @action: Unused.
>> + * @data: The ACPI event.
>> + *
>> + * For LWMI_EVENT_THERMAL_MODE, set current_mode and notify platform_profile
>> + * of a change.
>> + *
>> + * Return: notifier_block status.
>> + */
>> +static int lwmi_cd01_notifier_call(struct notifier_block *nb, unsigned long action,
>> +				   void *data)
>> +{
>> +	struct acpi_bus_event *event = data;
>> +	struct lwmi_cd01_priv *priv;
>> +	int ret;
>> +
>> +	if (strcmp(event->device_class, ACPI_AC_CLASS) != 0)
>> +		return NOTIFY_DONE;
>> +
>> +	priv = container_of(nb, struct lwmi_cd01_priv, acpi_nb);
>> +
>> +	switch (event->type) {
>> +	case ACPI_AC_NOTIFY_STATUS:
>> +		ret = lwmi_cd01_cache(priv);
>> +		if (ret)
>> +			return NOTIFY_BAD;
>> +
>> +		return NOTIFY_OK;
>> +	default:
>> +		return NOTIFY_DONE;
>> +	}
>> +}
>> +
>> +/**
>> + * lwmi_cd01_unregister() - Unregister the cd01 ACPI notifier_block.
>> + * @data: The ACPI event notifier_block to unregister.
>> + */
>> +static void lwmi_cd01_unregister(void *data)
>> +{
>> +	struct notifier_block *acpi_nb = data;
>> +
>> +	unregister_acpi_notifier(acpi_nb);
>> +}
>> +
>> +static int lwmi_cd01_probe(struct wmi_device *wdev, const void *context)
>> +
>> +{
>> +	struct lwmi_cd01_priv *priv;
>> +	int ret;
>> +
>> +	priv = devm_kzalloc(&wdev->dev, sizeof(*priv), GFP_KERNEL);
>> +	if (!priv)
>> +		return -ENOMEM;
>> +
>> +	priv->wdev = wdev;
>> +	dev_set_drvdata(&wdev->dev, priv);
>> +
>> +	ret = lwmi_cd01_setup(priv);
>> +	if (ret)
>> +		return ret;
>> +
>> +	priv->acpi_nb.notifier_call = lwmi_cd01_notifier_call;
>> +
>> +	ret = register_acpi_notifier(&priv->acpi_nb);
>> +	if (ret)
>> +		return ret;
>> +
>> +	devm_add_action_or_reset(&wdev->dev, lwmi_cd01_unregister, &priv->acpi_nb);
>
>Please check the return value of devm_add_action_or_reset() here.
>
>With those issues being fixed:
>
>Reviewed-by: Armin Wolf <W_Armin@....de>
>
>> +
>> +	return component_add(&wdev->dev, &lwmi_cd01_component_ops);
>> +}
>> +
>> +static void lwmi_cd01_remove(struct wmi_device *wdev)
>> +{
>> +	component_del(&wdev->dev, &lwmi_cd01_component_ops);
>> +}
>> +
>> +static const struct wmi_device_id lwmi_cd01_id_table[] = {
>> +	{ LENOVO_CAPABILITY_DATA_01_GUID, NULL },
>> +	{}
>> +};
>> +
>> +static struct wmi_driver lwmi_cd01_driver = {
>> +	.driver = {
>> +		.name = "lenovo_wmi_cd01",
>> +		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
>> +	},
>> +	.id_table = lwmi_cd01_id_table,
>> +	.probe = lwmi_cd01_probe,
>> +	.remove = lwmi_cd01_remove,
>> +	.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_cd01_driver.driver;
>> +}
>> +EXPORT_SYMBOL_NS_GPL(lwmi_cd01_match, "LENOVO_WMI_CD01");
>> +
>> +module_wmi_driver(lwmi_cd01_driver);
>> +
>> +MODULE_DEVICE_TABLE(wmi, lwmi_cd01_id_table);
>> +MODULE_AUTHOR("Derek J. Clark <derekjohn.clark@...il.com>");
>> +MODULE_DESCRIPTION("Lenovo Capability Data 01 WMI Driver");
>> +MODULE_LICENSE("GPL");
>> diff --git a/drivers/platform/x86/lenovo-wmi-capdata01.h b/drivers/platform/x86/lenovo-wmi-capdata01.h
>> new file mode 100644
>> index 000000000000..bd06c5751f68
>> --- /dev/null
>> +++ b/drivers/platform/x86/lenovo-wmi-capdata01.h
>> @@ -0,0 +1,25 @@
>> +/* SPDX-License-Identifier: GPL-2.0-or-later */
>> +
>> +/* Copyright (C) 2025 Derek J. Clark <derekjohn.clark@...il.com> */
>> +
>> +#ifndef _LENOVO_WMI_CAPDATA01_H_
>> +#define _LENOVO_WMI_CAPDATA01_H_
>> +
>> +#include <linux/types.h>
>> +
>> +struct device;
>> +struct cd01_list;
>> +
>> +struct capdata01 {
>> +	u32 id;
>> +	u32 supported;
>> +	u32 default_value;
>> +	u32 step;
>> +	u32 min_value;
>> +	u32 max_value;
>> +};
>> +
>> +int lwmi_cd01_get_data(struct cd01_list *list, u32 attribute_id, struct capdata01 *output);
>> +int lwmi_cd01_match(struct device *dev, void *data);
>> +
>> +#endif /* !_LENOVO_WMI_CAPDATA01_H_ */

- Derek

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