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 87
88 What: /sys/class/backlight/<backligh 88 What: /sys/class/backlight/<backlight>/<ambient light zone>_max
89 Date: Sep, 2009 89 Date: Sep, 2009
90 KernelVersion: v2.6.32 90 KernelVersion: v2.6.32
91 Contact: device-drivers-devel@blackfin. 91 Contact: device-drivers-devel@blackfin.uclinux.org
92 Description: 92 Description:
93 Control the maximum brightness 93 Control the maximum brightness for <ambient light zone>
94 on this <backlight>. Values ar 94 on this <backlight>. Values are between 0 and 127. This file
95 will also show the brightness 95 will also show the brightness level stored for this
96 <ambient light zone>. 96 <ambient light zone>.
97 97
98 The <ambient light zone> is de 98 The <ambient light zone> is device-driver specific:
99 99
100 For ADP5520 and ADP5501, <ambi 100 For ADP5520 and ADP5501, <ambient light zone> can be:
101 101
102 =========== ================= 102 =========== ================================================
103 Ambient sysfs entry 103 Ambient sysfs entry
104 light zone 104 light zone
105 =========== ================= 105 =========== ================================================
106 daylight /sys/class/backli 106 daylight /sys/class/backlight/<backlight>/daylight_max
107 office /sys/class/backli 107 office /sys/class/backlight/<backlight>/office_max
108 dark /sys/class/backli 108 dark /sys/class/backlight/<backlight>/dark_max
109 =========== ================= 109 =========== ================================================
110 110
111 For ADP8860, <ambient light zo 111 For ADP8860, <ambient light zone> can be:
112 112
113 =========== ================= 113 =========== ================================================
114 Ambient sysfs entry 114 Ambient sysfs entry
115 light zone 115 light zone
116 =========== ================= 116 =========== ================================================
117 l1_daylight /sys/class/backli 117 l1_daylight /sys/class/backlight/<backlight>/l1_daylight_max
118 l2_office /sys/class/backli 118 l2_office /sys/class/backlight/<backlight>/l2_office_max
119 l3_dark /sys/class/backli 119 l3_dark /sys/class/backlight/<backlight>/l3_dark_max
120 =========== ================= 120 =========== ================================================
121 121
122 For ADP8870, <ambient light zo 122 For ADP8870, <ambient light zone> can be:
123 123
124 =========== ================= 124 =========== ================================================
125 Ambient sysfs entry 125 Ambient sysfs entry
126 light zone 126 light zone
127 =========== ================= 127 =========== ================================================
128 l1_daylight /sys/class/backli 128 l1_daylight /sys/class/backlight/<backlight>/l1_daylight_max
129 l2_bright /sys/class/backli 129 l2_bright /sys/class/backlight/<backlight>/l2_bright_max
130 l3_office /sys/class/backli 130 l3_office /sys/class/backlight/<backlight>/l3_office_max
131 l4_indoor /sys/class/backli 131 l4_indoor /sys/class/backlight/<backlight>/l4_indoor_max
132 l5_dark /sys/class/backli 132 l5_dark /sys/class/backlight/<backlight>/l5_dark_max
133 =========== ================= 133 =========== ================================================
134 134
135 See also: /sys/class/backlight 135 See also: /sys/class/backlight/<backlight>/ambient_light_zone.
136 136
137 What: /sys/class/backlight/<backligh 137 What: /sys/class/backlight/<backlight>/<ambient light zone>_dim
138 Date: Sep, 2009 138 Date: Sep, 2009
139 KernelVersion: v2.6.32 139 KernelVersion: v2.6.32
140 Contact: device-drivers-devel@blackfin. 140 Contact: device-drivers-devel@blackfin.uclinux.org
141 Description: 141 Description:
142 Control the dim brightness for 142 Control the dim brightness for <ambient light zone>
143 on this <backlight>. Values ar 143 on this <backlight>. Values are between 0 and 127, typically
144 set to 0. Full off when the ba 144 set to 0. Full off when the backlight is disabled.
145 This file will also show the d 145 This file will also show the dim brightness level stored for
146 this <ambient light zone>. 146 this <ambient light zone>.
147 147
148 The <ambient light zone> is de 148 The <ambient light zone> is device-driver specific:
149 149
150 For ADP5520 and ADP5501, <ambi 150 For ADP5520 and ADP5501, <ambient light zone> can be:
151 151
152 =========== ================= 152 =========== ================================================
153 Ambient sysfs entry 153 Ambient sysfs entry
154 light zone 154 light zone
155 =========== ================= 155 =========== ================================================
156 daylight /sys/class/backli 156 daylight /sys/class/backlight/<backlight>/daylight_dim
157 office /sys/class/backli 157 office /sys/class/backlight/<backlight>/office_dim
158 dark /sys/class/backli 158 dark /sys/class/backlight/<backlight>/dark_dim
159 =========== ================= 159 =========== ================================================
160 160
161 For ADP8860, <ambient light zo 161 For ADP8860, <ambient light zone> can be:
162 162
163 =========== ================= 163 =========== ================================================
164 Ambient sysfs entry 164 Ambient sysfs entry
165 light zone 165 light zone
166 =========== ================= 166 =========== ================================================
167 l1_daylight /sys/class/backli 167 l1_daylight /sys/class/backlight/<backlight>/l1_daylight_dim
168 l2_office /sys/class/backli 168 l2_office /sys/class/backlight/<backlight>/l2_office_dim
169 l3_dark /sys/class/backli 169 l3_dark /sys/class/backlight/<backlight>/l3_dark_dim
170 =========== ================= 170 =========== ================================================
171 171
172 For ADP8870, <ambient light zo 172 For ADP8870, <ambient light zone> can be:
173 173
174 =========== ================= 174 =========== ================================================
175 Ambient sysfs entry 175 Ambient sysfs entry
176 light zone 176 light zone
177 =========== ================= 177 =========== ================================================
178 l1_daylight /sys/class/backli 178 l1_daylight /sys/class/backlight/<backlight>/l1_daylight_dim
179 l2_bright /sys/class/backli 179 l2_bright /sys/class/backlight/<backlight>/l2_bright_dim
180 l3_office /sys/class/backli 180 l3_office /sys/class/backlight/<backlight>/l3_office_dim
181 l4_indoor /sys/class/backli 181 l4_indoor /sys/class/backlight/<backlight>/l4_indoor_dim
182 l5_dark /sys/class/backli 182 l5_dark /sys/class/backlight/<backlight>/l5_dark_dim
183 =========== ================= 183 =========== ================================================
184 184
185 See also: /sys/class/backlight 185 See also: /sys/class/backlight/<backlight>/ambient_light_zone.
186 186
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