1 What: /sys/class/backlight/<backligh 1 What: /sys/class/backlight/<backlight>/scale
2 Date: July 2019 2 Date: July 2019
3 KernelVersion: 5.4 3 KernelVersion: 5.4
4 Contact: Daniel Thompson <daniel.thompso 4 Contact: Daniel Thompson <daniel.thompson@linaro.org>
5 Description: 5 Description:
6 Description of the scale of th 6 Description of the scale of the brightness curve.
7 7
8 The human eye senses brightnes 8 The human eye senses brightness approximately logarithmically,
9 hence linear changes in bright 9 hence linear changes in brightness are perceived as being
10 non-linear. To achieve a linea 10 non-linear. To achieve a linear perception of brightness changes
11 controls like sliders need to 11 controls like sliders need to apply a logarithmic mapping for
12 backlights with a linear brigh 12 backlights with a linear brightness curve.
13 13
14 Possible values of the attribu 14 Possible values of the attribute are:
15 15
16 unknown 16 unknown
17 The scale of the brightness 17 The scale of the brightness curve is unknown.
18 18
19 linear 19 linear
20 The brightness changes linea 20 The brightness changes linearly with each step. Brightness
21 controls should apply a loga 21 controls should apply a logarithmic mapping for a linear
22 perception. 22 perception.
23 23
24 non-linear 24 non-linear
25 The brightness changes non-l 25 The brightness changes non-linearly with each step. Brightness
26 controls should use a linear 26 controls should use a linear mapping for a linear perception.
27 27
28 What: /sys/class/backlight/<backligh 28 What: /sys/class/backlight/<backlight>/ambient_light_level
29 Date: Apr, 2010 29 Date: Apr, 2010
30 KernelVersion: v2.6.35 30 KernelVersion: v2.6.35
31 Contact: Michael Hennerich <michael.henn 31 Contact: Michael Hennerich <michael.hennerich@analog.com>
32 Description: 32 Description:
33 (RO) Get conversion value of t 33 (RO) Get conversion value of the light sensor.
34 34
35 The value is automatically upd 35 The value is automatically updated every 80 ms when the
36 light sensor is enabled. 36 light sensor is enabled.
37 37
38 The value range is device-driv 38 The value range is device-driver specific:
39 39
40 For ADP8870: 40 For ADP8870:
41 41
42 It returns integer between 0 42 It returns integer between 0 (dark) and 8000 (max ambient
43 brightness). 43 brightness).
44 44
45 For ADP8860: 45 For ADP8860:
46 46
47 It returns a 13-bits integer 47 It returns a 13-bits integer.
48 48
49 What: /sys/class/backlight/<backligh 49 What: /sys/class/backlight/<backlight>/ambient_light_zone
50 Date: Apr, 2010 50 Date: Apr, 2010
51 KernelVersion: v2.6.35 51 KernelVersion: v2.6.35
52 Contact: Michael Hennerich <michael.henn 52 Contact: Michael Hennerich <michael.hennerich@analog.com>,
53 device-drivers-devel@blackfin. 53 device-drivers-devel@blackfin.uclinux.org
54 54
55 Description: 55 Description:
56 (RW) Read or write the specifi 56 (RW) Read or write the specific brightness level at which the
57 backlight operates. 57 backlight operates.
58 58
59 The value meaning is device-dr 59 The value meaning is device-driver specific:
60 60
61 For ADP8860: 61 For ADP8860:
62 62
63 == ====================== 63 == ==========================
64 0 Off: Backlight set to 64 0 Off: Backlight set to 0 mA
65 1 Level 1: daylight 65 1 Level 1: daylight
66 2 Level 2: bright 66 2 Level 2: bright
67 3 Level 3: dark 67 3 Level 3: dark
68 == ====================== 68 == ==========================
69 69
70 For ADP8870: 70 For ADP8870:
71 71
72 == ====================== 72 == ==========================
73 0 Off: Backlight set to 73 0 Off: Backlight set to 0 mA
74 1 Level 1: daylight 74 1 Level 1: daylight
75 2 Level 2: bright 75 2 Level 2: bright
76 3 Level 3: office 76 3 Level 3: office
77 4 Level 4: indoor 77 4 Level 4: indoor
78 5 Level 5: dark 78 5 Level 5: dark
79 == ====================== 79 == ==========================
80 80
81 Writing 0 returns to normal/au 81 Writing 0 returns to normal/automatic ambient light level
82 operation. 82 operation.
83 83
84 It can be enabled by writing t 84 It can be enabled by writing the value stored in
85 /sys/class/backlight/<backligh 85 /sys/class/backlight/<backlight>/max_brightness to
86 /sys/class/backlight/<backligh 86 /sys/class/backlight/<backlight>/brightness.
87 <<
88 What: /sys/class/backlight/<backligh <<
89 Date: Sep, 2009 <<
90 KernelVersion: v2.6.32 <<
91 Contact: device-drivers-devel@blackfin. <<
92 Description: <<
93 Control the maximum brightness <<
94 on this <backlight>. Values ar <<
95 will also show the brightness <<
96 <ambient light zone>. <<
97 <<
98 The <ambient light zone> is de <<
99 <<
100 For ADP5520 and ADP5501, <ambi <<
101 <<
102 =========== ================= <<
103 Ambient sysfs entry <<
104 light zone <<
105 =========== ================= <<
106 daylight /sys/class/backli <<
107 office /sys/class/backli <<
108 dark /sys/class/backli <<
109 =========== ================= <<
110 <<
111 For ADP8860, <ambient light zo <<
112 <<
113 =========== ================= <<
114 Ambient sysfs entry <<
115 light zone <<
116 =========== ================= <<
117 l1_daylight /sys/class/backli <<
118 l2_office /sys/class/backli <<
119 l3_dark /sys/class/backli <<
120 =========== ================= <<
121 <<
122 For ADP8870, <ambient light zo <<
123 <<
124 =========== ================= <<
125 Ambient sysfs entry <<
126 light zone <<
127 =========== ================= <<
128 l1_daylight /sys/class/backli <<
129 l2_bright /sys/class/backli <<
130 l3_office /sys/class/backli <<
131 l4_indoor /sys/class/backli <<
132 l5_dark /sys/class/backli <<
133 =========== ================= <<
134 <<
135 See also: /sys/class/backlight <<
136 <<
137 What: /sys/class/backlight/<backligh <<
138 Date: Sep, 2009 <<
139 KernelVersion: v2.6.32 <<
140 Contact: device-drivers-devel@blackfin. <<
141 Description: <<
142 Control the dim brightness for <<
143 on this <backlight>. Values ar <<
144 set to 0. Full off when the ba <<
145 This file will also show the d <<
146 this <ambient light zone>. <<
147 <<
148 The <ambient light zone> is de <<
149 <<
150 For ADP5520 and ADP5501, <ambi <<
151 <<
152 =========== ================= <<
153 Ambient sysfs entry <<
154 light zone <<
155 =========== ================= <<
156 daylight /sys/class/backli <<
157 office /sys/class/backli <<
158 dark /sys/class/backli <<
159 =========== ================= <<
160 <<
161 For ADP8860, <ambient light zo <<
162 <<
163 =========== ================= <<
164 Ambient sysfs entry <<
165 light zone <<
166 =========== ================= <<
167 l1_daylight /sys/class/backli <<
168 l2_office /sys/class/backli <<
169 l3_dark /sys/class/backli <<
170 =========== ================= <<
171 <<
172 For ADP8870, <ambient light zo <<
173 <<
174 =========== ================= <<
175 Ambient sysfs entry <<
176 light zone <<
177 =========== ================= <<
178 l1_daylight /sys/class/backli <<
179 l2_bright /sys/class/backli <<
180 l3_office /sys/class/backli <<
181 l4_indoor /sys/class/backli <<
182 l5_dark /sys/class/backli <<
183 =========== ================= <<
184 <<
185 See also: /sys/class/backlight <<
186 <<
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