[PATCH v2 05/16] backlight: improve backlight_properties documentation

[Sam Ravnborg <sam@ravnborg.org>]

Improve the documentation for backlight_properties and
adapt it to kernel-doc style.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Lee Jones <lee.jones@linaro.org>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Jingoo Han <jingoohan1@gmail.com>
---
 include/linux/backlight.h | 101 +++++++++++++++++++++++++++++++++-----
 1 file changed, 90 insertions(+), 11 deletions(-)

diff --git a/include/linux/backlight.h b/include/linux/backlight.h
index 519dc61ce7e4..7f9cef299d6e 100644
--- a/include/linux/backlight.h
+++ b/include/linux/backlight.h
@@ -118,28 +118,107 @@ struct backlight_ops {
 	int (*check_fb)(struct backlight_device *bd, struct fb_info *info);
 };
 
-/* This structure defines all the properties of a backlight */
+/**
+ * struct backlight_properties - backlight properties
+ *
+ * This structure defines all the properties of a backlight.
+ */
 struct backlight_properties {
-	/* Current User requested brightness (0 - max_brightness) */
+	/**
+	 * @brightness:
+	 *
+	 * The current requested brightness by the user.
+	 * The backlight core makes sure the range is (0 - max_brightness)
+	 * when the brightness is set via the sysfs attribute:
+	 * /sys/class/backlight/<backlight>/brightness.
+	 *
+	 * This value can be set in the backlight_properties passed
+	 * to devm_backlight_device_register() to set a default brightness
+	 * value.
+	 */
 	int brightness;
-	/* Maximal value for brightness (read-only) */
+
+	/**
+	 * @max_brightness:
+	 *
+	 * The maximum brightness value.
+	 *
+	 * This value must be set in the backlight_properties passed
+	 * to devm_backlight_device_register().
+	 *
+	 * This property must not be modified by a driver except
+	 * before registering the backlight device as explained above.
+	 */
 	int max_brightness;
-	/* Current FB Power mode (0: full on, 1..3: power saving
-	   modes; 4: full off), see FB_BLANK_XXX */
+
+	/**
+	 * @power:
+	 *
+	 * The current power mode. User space configure the power mode using
+	 * the sysfs attribute: /sys/class/backlight/<backlight>/bl_power
+	 * When the power property is updated update_status() is called.
+	 *
+	 * The possible values are: (0: full on, 1..3: power saving
+	 * modes; 4: full off), see FB_BLANK_XXX.
+	 *
+	 * When the backlight device is enabled @power is set
+	 * to FB_BLANK_UNBLANK. When the backlight device is disabled
+	 * @power is set to FB_BLANK_POWERDOWN.
+	 */
 	int power;
-	/* FB Blanking active? (values as for power) */
-	/* Due to be removed, please use (state & BL_CORE_FBBLANK) */
+
+	/**
+	 * @fb_blank:
+	 *
+	 * When the FBIOBLANK ioctl is called fb_blank is set to the
+	 * blank parameter and the update_status() operation is called.
+	 *
+	 * When the backlight device is enabled @fb_blank is set
+	 * to FB_BLANK_UNBLANK. When the backlight device is disabled
+	 * @fb_blank is set to FB_BLANK_POWERDOWN.
+	 *
+	 * This property must not be modified by a driver.
+	 * The backlight driver shall never read this variable,
+	 * as the necessary info is avaialble via the state.
+	 *
+	 * fb_blank is deprecated and will be removed.
+	 */
 	int fb_blank;
-	/* Backlight type */
+
+	/**
+	 * @type:
+	 *
+	 * The type of backlight supported.
+	 * The backlight type allows userspace to make appropriate
+	 * policy desicions based on the backlight type.
+	 *
+	 * This value must be set in the backlight_properties
+	 * passed to devm_backlight_device_register().
+	 */
 	enum backlight_type type;
-	/* Flags used to signal drivers of state changes */
+
+	/**
+	 * @state:
+	 *
+	 * The state property is used to inform drivers of state changes
+	 * when the update_status() operation is called.
+	 * The state is a bitmask. BL_CORE_FBBLANK is set when the display
+	 * is expected to be blank. BL_CORE_SUSPENDED is set when the
+	 * driver is suspended.
+	 *
+	 * This property must not be modified by a driver.
+	 */
 	unsigned int state;
-	/* Type of the brightness scale (linear, non-linear, ...) */
-	enum backlight_scale scale;
 
 #define BL_CORE_SUSPENDED	(1 << 0)	/* backlight is suspended */
 #define BL_CORE_FBBLANK		(1 << 1)	/* backlight is under an fb blank event */
 
+	/**
+	 * @scale:
+	 *
+	 * The type of the brightness scale (linear, non-linear, ...)
+	 */
+	enum backlight_scale scale;
 };
 
 struct backlight_device {
-- 
2.25.1

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