What: /sys/class/backlight/<backlight>/scale
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Date: July 2019
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KernelVersion: 5.4
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Contact: Daniel Thompson <daniel.thompson@linaro.org>
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Description:
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Description of the scale of the brightness curve.
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The human eye senses brightness approximately logarithmically,
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hence linear changes in brightness are perceived as being
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non-linear. To achieve a linear perception of brightness changes
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controls like sliders need to apply a logarithmic mapping for
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backlights with a linear brightness curve.
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Possible values of the attribute are:
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unknown
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The scale of the brightness curve is unknown.
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linear
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The brightness changes linearly with each step. Brightness
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controls should apply a logarithmic mapping for a linear
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perception.
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non-linear
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The brightness changes non-linearly with each step. Brightness
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controls should use a linear mapping for a linear perception.
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What: /sys/class/backlight/<backlight>/ambient_light_level
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Date: Apr, 2010
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KernelVersion: v2.6.35
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Contact: Michael Hennerich <michael.hennerich@analog.com>
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Description:
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(RO) Get conversion value of the light sensor.
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The value is automatically updated every 80 ms when the
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light sensor is enabled.
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The value range is device-driver specific:
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For ADP8870:
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It returns integer between 0 (dark) and 8000 (max ambient
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brightness).
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For ADP8860:
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It returns a 13-bits integer.
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What: /sys/class/backlight/<backlight>/ambient_light_zone
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Date: Apr, 2010
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KernelVersion: v2.6.35
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Contact: Michael Hennerich <michael.hennerich@analog.com>,
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device-drivers-devel@blackfin.uclinux.org
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Description:
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(RW) Read or write the specific brightness level at which the
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backlight operates.
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The value meaning is device-driver specific:
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For ADP8860:
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== ==========================
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0 Off: Backlight set to 0 mA
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1 Level 1: daylight
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2 Level 2: bright
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3 Level 3: dark
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== ==========================
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For ADP8870:
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== ==========================
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0 Off: Backlight set to 0 mA
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1 Level 1: daylight
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2 Level 2: bright
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3 Level 3: office
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4 Level 4: indoor
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5 Level 5: dark
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== ==========================
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Writing 0 returns to normal/automatic ambient light level
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operation.
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It can be enabled by writing the value stored in
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/sys/class/backlight/<backlight>/max_brightness to
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/sys/class/backlight/<backlight>/brightness.
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