ACPI: platform_profile: Add documentation

Add kerneldoc and sysfs class documentation.

Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Kurt Borja <kuurtb@gmail.com>
Reviewed-by: Mark Pearson <mpearson-lenovo@squebb.ca>
Tested-by: Mark Pearson <mpearson-lenovo@squebb.ca>
Link: https://lore.kernel.org/r/20250116002721.75592-19-kuurtb@gmail.com
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

Documentation/ABI/testing/sysfs-class-platform-profile

@@ -0,0 +1,48 @@
+What:		/sys/class/platform-profile/platform-profile-X/name
+Date:		March 2025
+KernelVersion:	6.14
+Description:	Name of the class device given by the driver.
+
+		RO
+
+What:		/sys/class/platform-profile/platform-profile-X/choices
+Date:		March 2025
+KernelVersion:	6.14
+Description:	This file contains a space-separated list of profiles supported
+		for this device.
+
+		Drivers must use the following standard profile-names:
+
+		====================	========================================
+		low-power		Low power consumption
+		cool			Cooler operation
+		quiet			Quieter operation
+		balanced		Balance between low power consumption
+					and performance
+		balanced-performance	Balance between performance and low
+					power consumption with a slight bias
+					towards performance
+		performance		High performance operation
+		custom			Driver defined custom profile
+		====================	========================================
+
+		RO
+
+What:		/sys/class/platform-profile/platform-profile-X/profile
+Date:		March 2025
+KernelVersion:	6.14
+Description:	Reading this file gives the current selected profile for this
+		device. Writing this file with one of the strings from
+		platform_profile_choices changes the profile to the new value.
+
+		This file can be monitored for changes by polling for POLLPRI,
+		POLLPRI will be signaled on any changes, independent of those
+		changes coming from a userspace write; or coming from another
+		source such as e.g. a hotkey triggered profile change handled
+		either directly by the embedded-controller or fully handled
+		inside the kernel.
+
+		This file may also emit the string 'custom' to indicate
+		that the driver is using a driver defined custom profile.
+
+		RW

drivers/acpi/platform_profile.c

@@ -425,6 +425,10 @@ static const struct attribute_group platform_profile_group = {
 	.is_visible = profile_class_is_visible,
 };
 
+/**
+ * platform_profile_notify - Notify class device and legacy sysfs interface
+ * @dev: The class device
+ */
 void platform_profile_notify(struct device *dev)
 {
 	scoped_cond_guard(mutex_intr, return, &profile_lock) {
@@ -434,6 +438,11 @@ void platform_profile_notify(struct device *dev)
 }
 EXPORT_SYMBOL_GPL(platform_profile_notify);
 
+/**
+ * platform_profile_cycle - Cycles profiles available on all registered class devices
+ *
+ * Return: 0 on success, -errno on failure
+ */
 int platform_profile_cycle(void)
 {
 	enum platform_profile_option next = PLATFORM_PROFILE_LAST;
@@ -477,6 +486,15 @@ int platform_profile_cycle(void)
 }
 EXPORT_SYMBOL_GPL(platform_profile_cycle);
 
+/**
+ * platform_profile_register - Creates and registers a platform profile class device
+ * @dev: Parent device
+ * @name: Name of the class device
+ * @drvdata: Driver data that will be attached to the class device
+ * @ops: Platform profile's mandatory operations
+ *
+ * Return: pointer to the new class device on success, ERR_PTR on failure
+ */
 struct device *platform_profile_register(struct device *dev, const char *name,
 					 void *drvdata,
 					 const struct platform_profile_ops *ops)
@@ -546,6 +564,12 @@ struct device *platform_profile_register(struct device *dev, const char *name,
 }
 EXPORT_SYMBOL_GPL(platform_profile_register);
 
+/**
+ * platform_profile_remove - Unregisters a platform profile class device
+ * @dev: Class device
+ *
+ * Return: 0
+ */
 int platform_profile_remove(struct device *dev)
 {
 	struct platform_profile_handler *pprof = to_pprof_handler(dev);
@@ -571,6 +595,15 @@ static void devm_platform_profile_release(struct device *dev, void *res)
 	platform_profile_remove(*ppdev);
 }
 
+/**
+ * devm_platform_profile_register - Device managed version of platform_profile_register
+ * @dev: Parent device
+ * @name: Name of the class device
+ * @drvdata: Driver data that will be attached to the class device
+ * @ops: Platform profile's mandatory operations
+ *
+ * Return: pointer to the new class device on success, ERR_PTR on failure
+ */
 struct device *devm_platform_profile_register(struct device *dev, const char *name,
 					      void *drvdata,
 					      const struct platform_profile_ops *ops)

include/linux/platform_profile.h

@@ -28,6 +28,16 @@ enum platform_profile_option {
 	PLATFORM_PROFILE_LAST, /*must always be last */
 };
 
+/**
+ * struct platform_profile_ops - platform profile operations
+ * @probe: Callback to setup choices available to the new class device. These
+ *	   choices will only be enforced when setting a new profile, not when
+ *	   getting the current one.
+ * @profile_get: Callback that will be called when showing the current platform
+ *		 profile in sysfs.
+ * @profile_set: Callback that will be called when storing a new platform
+ *		 profile in sysfs.
+ */
 struct platform_profile_ops {
 	int (*probe)(void *drvdata, unsigned long *choices);
 	int (*profile_get)(struct device *dev, enum platform_profile_option *profile);