backlight: backlight: Document enums in backlight.h

Add kernel-doc documentation for the backlight enums
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

include/linux/backlight.h

@@ -14,26 +14,98 @@
 #include <linux/mutex.h>
 #include <linux/notifier.h>
 
+/**
+ * enum backlight_update_reason - what method was used to update backlight
+ *
+ * A driver indicates the method (reason) used for updating the backlight
+ * when calling backlight_force_update().
+ */
 enum backlight_update_reason {
+	/**
+	 * @BACKLIGHT_UPDATE_HOTKEY: The backlight was updated using a hot-key.
+	 */
 	BACKLIGHT_UPDATE_HOTKEY,
+
+	/**
+	 * @BACKLIGHT_UPDATE_SYSFS: The backlight was updated using sysfs.
+	 */
 	BACKLIGHT_UPDATE_SYSFS,
 };
 
+/**
+ * enum backlight_type - the type of backlight control
+ *
+ * The type of interface used to control the backlight.
+ */
 enum backlight_type {
+	/**
+	 * @BACKLIGHT_RAW:
+	 *
+	 * The backlight is controlled using hardware registers.
+	 */
 	BACKLIGHT_RAW = 1,
+
+	/**
+	 * @BACKLIGHT_PLATFORM:
+	 *
+	 * The backlight is controlled using a platform-specific interface.
+	 */
 	BACKLIGHT_PLATFORM,
+
+	/**
+	 * @BACKLIGHT_FIRMWARE:
+	 *
+	 * The backlight is controlled using a standard firmware interface.
+	 */
 	BACKLIGHT_FIRMWARE,
+
+	/**
+	 * @BACKLIGHT_TYPE_MAX: Number of entries.
+	 */
 	BACKLIGHT_TYPE_MAX,
 };
 
+/**
+ * enum backlight_notification - the type of notification
+ *
+ * The notifications that is used for notification sent to the receiver
+ * that registered notifications using backlight_register_notifier().
+ */
 enum backlight_notification {
+	/**
+	 * @BACKLIGHT_REGISTERED: The backlight device is registered.
+	 */
 	BACKLIGHT_REGISTERED,
+
+	/**
+	 * @BACKLIGHT_UNREGISTERED: The backlight revice is unregistered.
+	 */
 	BACKLIGHT_UNREGISTERED,
 };
 
+/** enum backlight_scale - the type of scale used for brightness values
+ *
+ * The type of scale used for brightness values.
+ */
 enum backlight_scale {
+	/**
+	 * @BACKLIGHT_SCALE_UNKNOWN: The scale is unknown.
+	 */
 	BACKLIGHT_SCALE_UNKNOWN = 0,
+
+	/**
+	 * @BACKLIGHT_SCALE_LINEAR: The scale is linear.
+	 *
+	 * The linear scale will increase brightness the same for each step.
+	 */
 	BACKLIGHT_SCALE_LINEAR,
+
+	/**
+	 * @BACKLIGHT_SCALE_NON_LINEAR: The scale is not linear.
+	 *
+	 * This is often used when the brightness values tries to adjust to
+	 * the relative perception of the eye demanding a non-linear scale.
+	 */
 	BACKLIGHT_SCALE_NON_LINEAR,
 };