1What:		/sys/class/backlight/<backlight>/scale
2Date:		July 2019
3KernelVersion:	5.4
4Contact:	Daniel Thompson <daniel.thompson@linaro.org>
5Description:
6		Description of the scale of the brightness curve.
7
8		The human eye senses brightness approximately logarithmically,
9		hence linear changes in brightness are perceived as being
10		non-linear. To achieve a linear perception of brightness changes
11		controls like sliders need to apply a logarithmic mapping for
12		backlights with a linear brightness curve.
13
14		Possible values of the attribute are:
15
16		unknown
17		  The scale of the brightness curve is unknown.
18
19		linear
20		  The brightness changes linearly with each step. Brightness
21		  controls should apply a logarithmic mapping for a linear
22		  perception.
23
24		non-linear
25		  The brightness changes non-linearly with each step. Brightness
26		  controls should use a linear mapping for a linear perception.
27
28What:		/sys/class/backlight/<backlight>/ambient_light_level
29Date:		Apr, 2010
30KernelVersion:	v2.6.35
31Contact:	Michael Hennerich <michael.hennerich@analog.com>
32Description:
33		(RO) Get conversion value of the light sensor.
34
35		The value is automatically updated every 80 ms when the
36		light sensor is enabled.
37
38		The value range is device-driver specific:
39
40		For ADP8870:
41
42		  It returns integer between 0 (dark) and 8000 (max ambient
43		  brightness).
44
45		For ADP8860:
46
47		  It returns a 13-bits integer.
48
49What:		/sys/class/backlight/<backlight>/ambient_light_zone
50Date:		Apr, 2010
51KernelVersion:	v2.6.35
52Contact:	Michael Hennerich <michael.hennerich@analog.com>,
53		device-drivers-devel@blackfin.uclinux.org
54
55Description:
56		(RW) Read or write the specific brightness level at which the
57		backlight operates.
58
59		The value meaning is device-driver specific:
60
61		For ADP8860:
62
63		  ==	==========================
64		   0	Off: Backlight set to 0 mA
65		   1	Level 1: daylight
66		   2	Level 2: bright
67		   3	Level 3: dark
68		  ==	==========================
69
70		For ADP8870:
71
72		  ==	==========================
73		   0	Off: Backlight set to 0 mA
74		   1	Level 1: daylight
75		   2	Level 2: bright
76		   3	Level 3: office
77		   4	Level 4: indoor
78		   5	Level 5: dark
79		  ==	==========================
80
81		Writing 0 returns to normal/automatic ambient light level
82		operation.
83
84		It can be enabled by writing the value stored in
85		/sys/class/backlight/<backlight>/max_brightness to
86		/sys/class/backlight/<backlight>/brightness.
87