kernel/linux.git/drivers/video/backlight/backlight.c, branch v6.1.168

backlight: backlight: Slighly simplify devm_of_find_backlight()

2022-03-08T10:47:28+00:00

Use devm_add_action_or_reset() instead of devm_add_action()+hand writing what is done in the release function, should an error occur. This is more straightforward and saves a few lines of code. While at it, remove a useless test in devm_backlight_release(). 'data' is known to be not NULL when this function is called. Signed-off-by: Christophe JAILLET Reviewed-by: Daniel Thompson Signed-off-by: Lee Jones Link: https://lore.kernel.org/r/f998a4291d865273afa0d1f85764a9ac7fbc1b64.1644738084.git.christophe.jaillet@wanadoo.fr

backlight: Propagate errors from get_brightness()

2021-09-23T09:48:00+00:00

backlight.h documents "struct backlight_ops->get_brightness()" to return a negative errno on failure. So far these errors have not been handled in the backlight core. This leads to negative values being exposed through sysfs although only positive values are documented to be reported. Signed-off-by: Thomas Weißschuh Reviewed-by: Daniel Thompson Signed-off-by: Lee Jones

video: backlight: Drop maximum brightness override for brightness zero

2021-09-22T07:32:48+00:00

The note in c2adda27d202f ("video: backlight: Add of_find_backlight helper in backlight.c") says that gpio-backlight uses brightness as power state. This has been fixed since in ec665b756e6f7 ("backlight: gpio-backlight: Correct initial power state handling") and other backlight drivers do not require this workaround. Drop the workaround. This fixes the case where e.g. pwm-backlight can perfectly well be set to brightness 0 on boot in DT, which without this patch leads to the display brightness to be max instead of off. Fixes: c2adda27d202f ("video: backlight: Add of_find_backlight helper in backlight.c") Cc: # 5.4+ Cc: # 4.19.x: ec665b756e6f7: backlight: gpio-backlight: Correct initial power state handling Signed-off-by: Marek Vasut Acked-by: Noralf Trønnes Reviewed-by: Daniel Thompson Signed-off-by: Lee Jones

backlight: backlight: Make of_find_backlight static

2020-07-20T09:27:11+00:00

There are no external users of of_find_backlight, as they have all changed to use the managed version. Make of_find_backlight static to prevent new external users. Signed-off-by: Sam Ravnborg Reviewed-by: Daniel Thompson Signed-off-by: Lee Jones

backlight: backlight: Drop backlight_put()

2020-07-20T09:27:09+00:00

There are no external users of backlight_put(). Drop it and open code the two users in backlight.c. Signed-off-by: Sam Ravnborg Reviewed-by: Daniel Thompson Signed-off-by: Lee Jones

backlight: backlight: Add overview and update existing doc

2020-07-20T09:26:20+00:00

Add overview chapter to backlight.c. Update existing kernel-doc to follow a more consistent style and drop kernel-doc for deprecated functions. Signed-off-by: Sam Ravnborg Reviewed-by: Daniel Thompson Reviewed-by: Emil Velikov Signed-off-by: Lee Jones

backlight: backlight: Refactor fb_notifier_callback()

2020-07-20T09:17:04+00:00

Increase readability of fb_notifier_callback() by removing a few indent levels. No functional change. Signed-off-by: Sam Ravnborg Reviewed-by: Daniel Thompson Reviewed-by: Emil Velikov Signed-off-by: Lee Jones

backlight: backlight: Supply description for function args in existing Kerneldocs

2020-07-06T07:11:42+00:00

Kerneldoc syntax is used, but not complete. Descriptions required. Prevents warnings like: drivers/video/backlight/backlight.c:329: warning: Function parameter or member 'reason' not described in 'backlight_force_update' drivers/video/backlight/backlight.c:354: warning: Function parameter or member 'props' not described in 'backlight_device_register' Cc: Bartlomiej Zolnierkiewicz Cc: Jamey Hicks Cc: Andrew Zabolotny Signed-off-by: Lee Jones Reviewed-by: Daniel Thompson Reviewed-by: Sam Ravnborg Signed-off-by: Lee Jones

backlight: Add backlight_device_get_by_name()

2020-05-11T06:39:16+00:00

Add a way to lookup a backlight device based on its name. Will be used by a USB display gadget getting the name from configfs. Signed-off-by: Noralf Trønnes Reviewed-by: Sam Ravnborg Reviewed-by: Daniel Thompson Acked-by: Jingoo Han Signed-off-by: Lee Jones

backlight: Expose brightness curve type through sysfs

2019-09-02T14:55:03+00:00

Backlight brightness curves can have different shapes. The two main types are linear and non-linear curves. The human eye doesn't perceive linearly increasing/decreasing brightness as linear (see also 88ba95bedb79 "backlight: pwm_bl: Compute brightness of LED linearly to human eye"), hence many backlights use non-linear (often logarithmic) brightness curves. The type of curve currently is opaque to userspace, so userspace often uses more or less reliable heuristics (like the number of brightness levels) to decide whether to treat a backlight device as linear or non-linear. Export the type of the brightness curve via the new sysfs attribute 'scale'. The value of the attribute can be 'linear', 'non-linear' or 'unknown'. For devices that don't provide information about the scale of their brightness curve the value of the 'scale' attribute is 'unknown'. Signed-off-by: Matthias Kaehlcke Reviewed-by: Daniel Thompson Signed-off-by: Lee Jones