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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.
+
+What: /sys/class/backlight/<backlight>/<ambient light zone>_max
+Date: Sep, 2009
+KernelVersion: v2.6.32
+Contact: device-drivers-devel@blackfin.uclinux.org
+Description:
+ Control the maximum brightness for <ambient light zone>
+ on this <backlight>. Values are between 0 and 127. This file
+ will also show the brightness level stored for this
+ <ambient light zone>.
+
+ The <ambient light zone> is device-driver specific:
+
+ For ADP5520 and ADP5501, <ambient light zone> can be:
+
+ =========== ================================================
+ Ambient sysfs entry
+ light zone
+ =========== ================================================
+ daylight /sys/class/backlight/<backlight>/daylight_max
+ office /sys/class/backlight/<backlight>/office_max
+ dark /sys/class/backlight/<backlight>/dark_max
+ =========== ================================================
+
+ For ADP8860, <ambient light zone> can be:
+
+ =========== ================================================
+ Ambient sysfs entry
+ light zone
+ =========== ================================================
+ l1_daylight /sys/class/backlight/<backlight>/l1_daylight_max
+ l2_office /sys/class/backlight/<backlight>/l2_office_max
+ l3_dark /sys/class/backlight/<backlight>/l3_dark_max
+ =========== ================================================
+
+ For ADP8870, <ambient light zone> can be:
+
+ =========== ================================================
+ Ambient sysfs entry
+ light zone
+ =========== ================================================
+ l1_daylight /sys/class/backlight/<backlight>/l1_daylight_max
+ l2_bright /sys/class/backlight/<backlight>/l2_bright_max
+ l3_office /sys/class/backlight/<backlight>/l3_office_max
+ l4_indoor /sys/class/backlight/<backlight>/l4_indoor_max
+ l5_dark /sys/class/backlight/<backlight>/l5_dark_max
+ =========== ================================================
+
+ See also: /sys/class/backlight/<backlight>/ambient_light_zone.
+
+What: /sys/class/backlight/<backlight>/<ambient light zone>_dim
+Date: Sep, 2009
+KernelVersion: v2.6.32
+Contact: device-drivers-devel@blackfin.uclinux.org
+Description:
+ Control the dim brightness for <ambient light zone>
+ on this <backlight>. Values are between 0 and 127, typically
+ set to 0. Full off when the backlight is disabled.
+ This file will also show the dim brightness level stored for
+ this <ambient light zone>.
+
+ The <ambient light zone> is device-driver specific:
+
+ For ADP5520 and ADP5501, <ambient light zone> can be:
+
+ =========== ================================================
+ Ambient sysfs entry
+ light zone
+ =========== ================================================
+ daylight /sys/class/backlight/<backlight>/daylight_dim
+ office /sys/class/backlight/<backlight>/office_dim
+ dark /sys/class/backlight/<backlight>/dark_dim
+ =========== ================================================
+
+ For ADP8860, <ambient light zone> can be:
+
+ =========== ================================================
+ Ambient sysfs entry
+ light zone
+ =========== ================================================
+ l1_daylight /sys/class/backlight/<backlight>/l1_daylight_dim
+ l2_office /sys/class/backlight/<backlight>/l2_office_dim
+ l3_dark /sys/class/backlight/<backlight>/l3_dark_dim
+ =========== ================================================
+
+ For ADP8870, <ambient light zone> can be:
+
+ =========== ================================================
+ Ambient sysfs entry
+ light zone
+ =========== ================================================
+ l1_daylight /sys/class/backlight/<backlight>/l1_daylight_dim
+ l2_bright /sys/class/backlight/<backlight>/l2_bright_dim
+ l3_office /sys/class/backlight/<backlight>/l3_office_dim
+ l4_indoor /sys/class/backlight/<backlight>/l4_indoor_dim
+ l5_dark /sys/class/backlight/<backlight>/l5_dark_dim
+ =========== ================================================
+
+ See also: /sys/class/backlight/<backlight>/ambient_light_zone.
+