From cabf161335ca9fe695bb87469ed99be881cd08f5 Mon Sep 17 00:00:00 2001 From: Sam Ravnborg Date: Sun, 19 Jul 2020 10:07:28 +0200 Subject: [PATCH] backlight: backlight: Improve backlight_properties documentation Improve the documentation for backlight_properties and adapt it to kernel-doc style. Signed-off-by: Sam Ravnborg Reviewed-by: Daniel Thompson Reviewed-by: Emil Velikov Signed-off-by: Lee Jones --- include/linux/backlight.h | 96 +++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 85 insertions(+), 11 deletions(-) diff --git a/include/linux/backlight.h b/include/linux/backlight.h index 4ff6077..3554aef 100644 --- a/include/linux/backlight.h +++ b/include/linux/backlight.h @@ -117,28 +117,102 @@ 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 brightness requested by the user. + * + * The backlight core makes sure the range is (0 to max_brightness) + * when the brightness is set via the sysfs attribute: + * /sys/class/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() and shall not be modified by the + * driver after registration. + */ 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 can configure the power mode using the sysfs + * attribute: /sys/class/backlight//bl_power + * When the power property is updated update_status() is called. + * + * The possible values are: (0: full on, 1 to 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: The power state from the FBIOBLANK ioctl. + * + * 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. + * + * Backlight drivers should avoid using this property. It has been + * replaced by state & BL_CORE_FBLANK (although most drivers should + * use backlight_is_blank() as the preferred means to get the blank + * 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 decisions 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 of the backlight core. + * + * 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. + * + * backlight drivers are expected to use backlight_is_blank() + * in their update_status() operation rather than reading the + * state property. + * + * The state is maintained by the core and drivers may not modify it. + */ 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. + */ + enum backlight_scale scale; }; struct backlight_device { -- 2.7.4