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Subject: Re: [PATCH 1/4] platform/x86: wmi: Add kernel doc comments
To:     Randy Dunlap <rdunlap@infradead.org>, hdegoede@redhat.com,
        markgross@kernel.org
Cc:     corbet@lwn.net, linux-doc@vger.kernel.org,
        platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20230420233226.14561-1-W_Armin@gmx.de>
 <20230420233226.14561-2-W_Armin@gmx.de>
 <5a8effb3-e176-5a2f-4650-17765384e60c@infradead.org>
From:   Armin Wolf <W_Armin@gmx.de>
Message-ID: <ca9bac63-8700-3b37-0674-b1c16a137d2d@gmx.de>
Date:   Mon, 24 Apr 2023 23:20:46 +0200
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Precedence: bulk

Am 22.04.23 um 04:54 schrieb Randy Dunlap:

> Hi,
>
> On 4/20/23 16:32, Armin Wolf wrote:
>> Add kernel doc comments useful for documenting the functions/structs
>> used to interact with the WMI driver core.
>>
>> Signed-off-by: Armin Wolf <W_Armin@gmx.de>
>> ---
>>   drivers/platform/x86/wmi.c | 51 +++++++++++++++++++++++++++++++-------
>>   include/linux/wmi.h        | 41 +++++++++++++++++++++++++++---
>>   2 files changed, 80 insertions(+), 12 deletions(-)
>>
>> diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c
>> index d81319a502ef..e4b41dca70c7 100644
>> --- a/drivers/platform/x86/wmi.c
>> +++ b/drivers/platform/x86/wmi.c
>> @@ -248,7 +248,9 @@ static acpi_status get_event_data(const struct wmi_block *wblock, struct acpi_bu
>>    * @wdev: A wmi bus device from a driver
>>    * @length: Required buffer size
>>    *
>> - * Allocates memory needed for buffer, stores the buffer size in that memory
>> + * Allocates memory needed for buffer, stores the buffer size in that memory.
>> + *
>> + * Return: 0 on success or a negative error code for failure.
>>    */
>>   int set_required_buffer_size(struct wmi_device *wdev, u64 length)
>>   {
>> @@ -269,7 +271,9 @@ EXPORT_SYMBOL_GPL(set_required_buffer_size);
>>    * @in: Buffer containing input for the method call
>>    * @out: Empty buffer to return the method results
>>    *
>> - * Call an ACPI-WMI method
>> + * Call an ACPI-WMI method, the caller must free @out.
>> + *
>> + * Return: acpi_status signaling success or error.
>>    */
>>   acpi_status wmi_evaluate_method(const char *guid_string, u8 instance, u32 method_id,
>>   				const struct acpi_buffer *in, struct acpi_buffer *out)
>> @@ -294,7 +298,9 @@ EXPORT_SYMBOL_GPL(wmi_evaluate_method);
>>    * @in: Buffer containing input for the method call
>>    * @out: Empty buffer to return the method results
>>    *
>> - * Call an ACPI-WMI method
>> + * Call an ACPI-WMI method, the caller must free @out.
>> + *
>> + * Return: acpi_status signaling success or error.
>>    */
>>   acpi_status wmidev_evaluate_method(struct wmi_device *wdev, u8 instance, u32 method_id,
>>   				   const struct acpi_buffer *in, struct acpi_buffer *out)
>> @@ -411,7 +417,9 @@ static acpi_status __query_block(struct wmi_block *wblock, u8 instance,
>>    * @instance: Instance index
>>    * @out: Empty buffer to return the contents of the data block to
>>    *
>> - * Return the contents of an ACPI-WMI data block to a buffer
>> + * Query a ACPI-WMI block, the caller must free @out.
>> + *
>> + * Return: ACPI object containing the content of the WMI block.
>>    */
>>   acpi_status wmi_query_block(const char *guid_string, u8 instance,
>>   			    struct acpi_buffer *out)
>> @@ -427,6 +435,15 @@ acpi_status wmi_query_block(const char *guid_string, u8 instance,
>>   }
>>   EXPORT_SYMBOL_GPL(wmi_query_block);
>>
>> +/**
>> + * wmidev_block_query - Return contents of a WMI block
>> + * @wdev: A wmi bus device from a driver
>> + * @instance: Instance index
>> + *
>> + * Query a ACPI-WMI block, the caller must free the result.
>        Query an ACPI-WMI block,
>
>> + *
>> + * Return: ACPI object containing the content of the WMI block.
>> + */
>>   union acpi_object *wmidev_block_query(struct wmi_device *wdev, u8 instance)
>>   {
>>   	struct acpi_buffer out = { ACPI_ALLOCATE_BUFFER, NULL };
>> @@ -445,7 +462,9 @@ EXPORT_SYMBOL_GPL(wmidev_block_query);
>>    * @instance: Instance index
>>    * @in: Buffer containing new values for the data block
>>    *
>> - * Write the contents of the input buffer to an ACPI-WMI data block
>> + * Write the contents of the input buffer to an ACPI-WMI data block.
>> + *
>> + * Return: acpi_status signaling success or error.
>>    */
>>   acpi_status wmi_set_block(const char *guid_string, u8 instance,
>>   			  const struct acpi_buffer *in)
>> @@ -555,6 +574,8 @@ static void wmi_notify_debug(u32 value, void *context)
>>    * @data: Data to be returned to handler when event is fired
>>    *
>>    * Register a handler for events sent to the ACPI-WMI mapper device.
>> + *
>> + * Return: acpi_status signaling success or error.
>>    */
>>   acpi_status wmi_install_notify_handler(const char *guid,
>>   				       wmi_notify_handler handler,
>> @@ -597,6 +618,8 @@ EXPORT_SYMBOL_GPL(wmi_install_notify_handler);
>>    * @guid: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
>>    *
>>    * Unregister handler for events sent to the ACPI-WMI mapper device.
>> + *
>> + * Return: acpi_status signaling success or error.
>>    */
>>   acpi_status wmi_remove_notify_handler(const char *guid)
>>   {
>> @@ -641,9 +664,11 @@ EXPORT_SYMBOL_GPL(wmi_remove_notify_handler);
>>    * wmi_get_event_data - Get WMI data associated with an event
>>    *
>>    * @event: Event to find
>> - * @out: Buffer to hold event data. out->pointer should be freed with kfree()
>> + * @out: Buffer to hold event data
>> + *
>> + * Get extra data associated with an WMI event, the caller needs to free @out.
>>    *
>> - * Returns extra data associated with an event in WMI.
>> + * Return: acpi_status signaling success or error.
>>    */
>>   acpi_status wmi_get_event_data(u32 event, struct acpi_buffer *out)
>>   {
>> @@ -664,7 +689,9 @@ EXPORT_SYMBOL_GPL(wmi_get_event_data);
>>    * wmi_has_guid - Check if a GUID is available
>>    * @guid_string: 36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
>>    *
>> - * Check if a given GUID is defined by _WDG
>> + * Check if a given GUID is defined by _WDG.
>> + *
>> + * Return: True if GUID is available, false otherwise.
>>    */
>>   bool wmi_has_guid(const char *guid_string)
>>   {
>> @@ -678,7 +705,7 @@ EXPORT_SYMBOL_GPL(wmi_has_guid);
>>    *
>>    * Find the _UID of ACPI device associated with this WMI GUID.
>>    *
>> - * Return: The ACPI _UID field value or NULL if the WMI GUID was not found
>> + * Return: The ACPI _UID field value or NULL if the WMI GUID was not found.
>>    */
>>   char *wmi_get_acpi_device_uid(const char *guid_string)
>>   {
>> @@ -1454,6 +1481,12 @@ int __must_check __wmi_driver_register(struct wmi_driver *driver,
>>   }
>>   EXPORT_SYMBOL(__wmi_driver_register);
>>
>> +/**
>> + * wmi_driver_unregister() - Unregister a WMI driver
>> + * @driver: WMI driver to unregister
>> + *
>> + * Unregisters a WMI driver from the WMI bus.
>> + */
>>   void wmi_driver_unregister(struct wmi_driver *driver)
>>   {
>>   	driver_unregister(&driver->driver);
>> diff --git a/include/linux/wmi.h b/include/linux/wmi.h
>> index b88d7b58e61e..88f66b12eef9 100644
>> --- a/include/linux/wmi.h
>> +++ b/include/linux/wmi.h
>> @@ -13,25 +13,44 @@
>>   #include <linux/mod_devicetable.h>
>>   #include <uapi/linux/wmi.h>
>>
>> +/**
>> + * struct wmi_device - WMI device structure
>> + * @dev: Device associated with this WMI device
>> + * @setable: True for devices implementing the Set Control Method
> private: fields are not normally documented in kernel-doc.

Hi,

since @setable is only used internally by the WMI driver core, i thought it might
be beneficial to exclude it from the normal driver interface documentation and only
use it for subsystem-internal documentation.

Armin Wolf

>> + *
>> + * This represents WMI devices discovered by the WMI driver core.
>> + */
>>   struct wmi_device {
>>   	struct device dev;
>>
>> -	 /* True for data blocks implementing the Set Control Method */
>> +	/* private: used by the WMI driver core */
>>   	bool setable;
>>   };
>>
>> -/* evaluate the ACPI method associated with this device */
>>   extern acpi_status wmidev_evaluate_method(struct wmi_device *wdev,
>>   					  u8 instance, u32 method_id,
>>   					  const struct acpi_buffer *in,
>>   					  struct acpi_buffer *out);
>>
>> -/* Caller must kfree the result. */
>>   extern union acpi_object *wmidev_block_query(struct wmi_device *wdev,
>>   					     u8 instance);
>>
>>   extern int set_required_buffer_size(struct wmi_device *wdev, u64 length);
>>
>> +/**
>> + * struct wmi_driver - WMI driver structure
>> + * @driver: Driver model structure
>> + * @id_table: List of WMI GUIDs supported by this driver
>> + * @no_notify_data: WMI events provide no event data
>> + * @probe: Callback for device binding
>> + * @remove: Callback for device unbinding
>> + * @notify: Callback for receiving WMI events
>> + * @filter_callback: Callback for filtering device IOCTLs
>> + *
>> + * This represents WMI drivers which handle WMI devices.
>> + * @filter_callback is only necessary for drivers which
>> + * want to set up a WMI IOCTL interface.
>> + */
>>   struct wmi_driver {
>>   	struct device_driver driver;
>>   	const struct wmi_device_id *id_table;
>> @@ -47,8 +66,24 @@ struct wmi_driver {
>>   extern int __must_check __wmi_driver_register(struct wmi_driver *driver,
>>   					      struct module *owner);
>>   extern void wmi_driver_unregister(struct wmi_driver *driver);
>> +
>> +/**
>> + * wmi_driver_register() - Helper macro ro register a WMI driver
> s/ro/to/
>
>> + * @driver: wmi_driver struct
>> + *
>> + * Helper macro for registering a WMI driver. It automatically passes
>> + * THIS_MODULE to the underlying function.
>> + */
>>   #define wmi_driver_register(driver) __wmi_driver_register((driver), THIS_MODULE)
>>
>> +/**
>> + * module_wmi_driver() - Helper macro to register/unregister a WMI driver
>> + * @__wmi_driver: wmi_driver struct
>> + *
>> + * Helper macro for WMI drivers which do not do anything special in module
>> + * init/exit. This eliminates a lot of boilerplate. Each module may only
>> + * use this macro once, and calling it replaces module_init() and module_exit().
>> + */
>>   #define module_wmi_driver(__wmi_driver) \
>>   	module_driver(__wmi_driver, wmi_driver_register, \
>>   		      wmi_driver_unregister)
>> --
> Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
> Tested-by: Randy Dunlap <rdunlap@infradead.org>
>
> Thanks.