Changes in sysfs-class-backlight

13d6f967 - docs: ABI: sysfs-class-backlight: unify ambient light zone nodes

Wed, 19 May 2021 08:51:45 +0000

docs: ABI: sysfs-class-backlight: unify ambient light zone nodes./scripts/get_abi.pl is warning about duplicated symboldefinition: Warning: /sys/class/backlight//l1_daylight_max is defined 2 times: ./Documentation/ABI/testing/sysfs-class-backlight-driver-adp8870:4 ./Documentation/ABI/testing/sysfs-class-backlight-adp8860:12What happens is that 3 drivers use the same pattern to reportmax and dim setting for different ambient light zones.It should be noticed that the adp8870 doc was missing anentry for l1_daylight_dim, which was fixed on this patch.While the ambient light zone is device-specific, the sysfsdefinition is actually common. So, unify them at: Documentation/ABI/testing/sysfs-class-backlightand use as the contact point, the e-mail reported byget_maintainers.pl for the subsystem.Signed-off-by: Mauro Carvalho Chehab Link: https://lore.kernel.org/r/c13c6ebd03cd04a0d15d89018f8d529918fc0a73.1621413933.git.mchehab+huawei@kernel.orgSigned-off-by: Jonathan Corbet List of files: /linux-6.15/Documentation/ABI/testing/sysfs-class-backlight

bd6e8441 - docs: ABI: sysfs-class-backlight: unify ABI documentation

Fri, 30 Oct 2020 07:40:56 +0000

docs: ABI: sysfs-class-backlight: unify ABI documentationBoth adp8860 and adp8870 define some extensions to thebacklight class. This causes warnings: Warning: /sys/class/backlight//ambient_light_level is defined 2 times: /sys/class/backlight//ambient_light_level:8 /sys/class/backlight//ambient_light_level:30 Warning: /sys/class/backlight//ambient_light_zone is defined 2 times: /sys/class/backlight//ambient_light_zone:18 /sys/class/backlight//ambient_light_zone:40As ABI definitions shouldn't be duplicated.Unfortunately, the ABI is dependent on the specific devicefeatures. As such, ambient_light_level range is somewhatdifferent among the supported devices.The ambient_light_zone is even worse: the meanings of eachpreset are different, and there's no ABI to retrievethe supported types nor their meanins. Unfortunately,it is too late to fix it without causing regressions,as this has been used since Kernel v2.6.35.Rewrite those ABI documentation using the current documentationas a reference, and double-checking at the datasheets: https://www.analog.com/media/en/technical-documentation/data-sheets/ADP8870.pdf https://www.analog.com/media/en/technical-documentation/data-sheets/ADP8860.pdfin order to properly document the differences between those twodrivers.Acked-by: Jonathan Corbet Signed-off-by: Mauro Carvalho Chehab Link: https://lore.kernel.org/r/342195ad5a819d9bcfcebc133c77ab69b4211672.1604042072.git.mchehab+huawei@kernel.orgSigned-off-by: Greg Kroah-Hartman List of files: /linux-6.15/Documentation/ABI/testing/sysfs-class-backlight

d55c028f - backlight: Expose brightness curve type through sysfs

Tue, 09 Jul 2019 19:00:05 +0000

backlight: Expose brightness curve type through sysfsBacklight brightness curves can have different shapes. The two maintypes are linear and non-linear curves. The human eye doesn'tperceive linearly increasing/decreasing brightness as linear (seealso 88ba95bedb79 "backlight: pwm_bl: Compute brightness of LEDlinearly to human eye"), hence many backlights use non-linear (oftenlogarithmic) brightness curves. The type of curve currently is opaqueto userspace, so userspace often uses more or less reliable heuristics(like the number of brightness levels) to decide whether to treat abacklight 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 scaleof 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 List of files: /linux-6.15/Documentation/ABI/testing/sysfs-class-backlight