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- 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.
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