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Diffstat (limited to 'Documentation/ABI/testing/sysfs-class-backlight')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-class-backlight | 86 |
1 files changed, 86 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-class-backlight b/Documentation/ABI/testing/sysfs-class-backlight new file mode 100644 index 000000000..1fc86401b --- /dev/null +++ b/Documentation/ABI/testing/sysfs-class-backlight @@ -0,0 +1,86 @@ +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. + +What: /sys/class/backlight/<backlight>/ambient_light_level +Date: Apr, 2010 +KernelVersion: v2.6.35 +Contact: Michael Hennerich <michael.hennerich@analog.com> +Description: + (RO) Get conversion value of the light sensor. + + The value is automatically updated every 80 ms when the + light sensor is enabled. + + The value range is device-driver specific: + + For ADP8870: + + It returns integer between 0 (dark) and 8000 (max ambient + brightness). + + For ADP8860: + + It returns a 13-bits integer. + +What: /sys/class/backlight/<backlight>/ambient_light_zone +Date: Apr, 2010 +KernelVersion: v2.6.35 +Contact: Michael Hennerich <michael.hennerich@analog.com>, + device-drivers-devel@blackfin.uclinux.org + +Description: + (RW) Read or write the specific brightness level at which the + backlight operates. + + The value meaning is device-driver specific: + + For ADP8860: + + == ========================== + 0 Off: Backlight set to 0 mA + 1 Level 1: daylight + 2 Level 2: bright + 3 Level 3: dark + == ========================== + + For ADP8870: + + == ========================== + 0 Off: Backlight set to 0 mA + 1 Level 1: daylight + 2 Level 2: bright + 3 Level 3: office + 4 Level 4: indoor + 5 Level 5: dark + == ========================== + + Writing 0 returns to normal/automatic ambient light level + operation. + + It can be enabled by writing the value stored in + /sys/class/backlight/<backlight>/max_brightness to + /sys/class/backlight/<backlight>/brightness. |