diff options
author | Linus Torvalds | 2019-09-23 19:33:56 -0700 |
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committer | Linus Torvalds | 2019-09-23 19:33:56 -0700 |
commit | d0b3cfee333eb7eecb6ce72f06f5a02d249b9bdf (patch) | |
tree | bd884989b8e0d08a64cb40384819a6e670ccf470 /Documentation | |
parent | 299d14d4c31aff3b37a03894e012edf8421676ee (diff) | |
parent | c0b64faf0fe6ca2574a00faed1ae833130db4e08 (diff) |
Merge tag 'backlight-next-5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight
Pull backlight updates from Lee Jones:
"Core Frameworks
- Obtain scale type through sysfs
New Functionality:
- Provide Device Tree functionality in rave-sp-backlight
- Calculate if scale type is (non-)linear in pwm_bl
Fix-ups:
- Simplify code in lm3630a_bl
- Trivial rename/whitespace/typo fixes in lms283gf05
- Remove superfluous NULL check in tosa_lcd
- Fix power state initialisation in gpio_backlight
- List supported file in MAINTAINERS
Bug Fixes:
- Kconfig - default to not building unless requested in
{LED,BACKLIGHT}_CLASS_DEVICE"
* tag 'backlight-next-5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight:
backlight: pwm_bl: Set scale type for brightness curves specified in the DT
backlight: pwm_bl: Set scale type for CIE 1931 curves
backlight: Expose brightness curve type through sysfs
MAINTAINERS: Add entry for stable backlight sysfs ABI documentation
backlight: gpio-backlight: Correct initial power state handling
video: backlight: tosa_lcd: drop check because i2c_unregister_device() is NULL safe
video: backlight: Drop default m for {LCD,BACKLIGHT_CLASS_DEVICE}
backlight: lms283gf05: Fix a typo in the description passed to 'devm_gpio_request_one()'
backlight: lm3630a: Switch to use fwnode_property_count_uXX()
backlight: rave-sp: Leave initial state and register with correct device
Diffstat (limited to 'Documentation')
-rw-r--r-- | Documentation/ABI/testing/sysfs-class-backlight | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-class-backlight b/Documentation/ABI/testing/sysfs-class-backlight new file mode 100644 index 000000000000..3ab175a3f5cb --- /dev/null +++ b/Documentation/ABI/testing/sysfs-class-backlight @@ -0,0 +1,26 @@ +What: /sys/class/backlight/<backlight>/scale +Date: July 2019 +KernelVersion: 5.4 +Contact: Daniel Thompson <daniel.thompson@linaro.org> +Description: + Description of the scale of the brightness curve. + + The human eye senses brightness approximately logarithmically, + hence linear changes in brightness are perceived as being + non-linear. To achieve a linear perception of brightness changes + controls like sliders need to apply a logarithmic mapping for + backlights with a linear brightness curve. + + Possible values of the attribute are: + + unknown + The scale of the brightness curve is unknown. + + linear + The brightness changes linearly with each step. Brightness + controls should apply a logarithmic mapping for a linear + perception. + + non-linear + The brightness changes non-linearly with each step. Brightness + controls should use a linear mapping for a linear perception. |