Documentation/ABI/testing/sysfs-class-backlight

   1 What:           /sys/class/backlight/<backlight>/scale
   2 Date:           July 2019
   3 KernelVersion:  5.4
   4 Contact:        Daniel Thompson <daniel.thompson@linaro.org>
   5 Description:
   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
  28 What:           /sys/class/backlight/<backlight>/ambient_light_level
  29 Date:           Apr, 2010
  30 KernelVersion:  v2.6.35
  31 Contact:        Michael Hennerich <michael.hennerich@analog.com>
  32 Description:
  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
  49 What:           /sys/class/backlight/<backlight>/ambient_light_zone
  50 Date:           Apr, 2010
  51 KernelVersion:  v2.6.35
  52 Contact:        Michael Hennerich <michael.hennerich@analog.com>,
  53                 device-drivers-devel@blackfin.uclinux.org
  54
  55 Description:
  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
  88 What:           /sys/class/backlight/<backlight>/<ambient light zone>_max
  89 Date:           Sep, 2009
  90 KernelVersion:  v2.6.32
  91 Contact:        device-drivers-devel@blackfin.uclinux.org
  92 Description:
  93                 Control the maximum brightness for <ambient light zone>
  94                 on this <backlight>. Values are between 0 and 127. This file
  95                 will also show the brightness level stored for this
  96                 <ambient light zone>.
  97
  98                 The <ambient light zone> is device-driver specific:
  99
 100                 For ADP5520 and ADP5501, <ambient light zone> can be:
 101
 102                 ===========  ================================================
 103                 Ambient      sysfs entry
 104                 light zone
 105                 ===========  ================================================
 106                 daylight     /sys/class/backlight/<backlight>/daylight_max
 107                 office       /sys/class/backlight/<backlight>/office_max
 108                 dark         /sys/class/backlight/<backlight>/dark_max
 109                 ===========  ================================================
 110
 111                 For ADP8860, <ambient light zone> can be:
 112
 113                 ===========  ================================================
 114                 Ambient      sysfs entry
 115                 light zone
 116                 ===========  ================================================
 117                 l1_daylight  /sys/class/backlight/<backlight>/l1_daylight_max
 118                 l2_office    /sys/class/backlight/<backlight>/l2_office_max
 119                 l3_dark      /sys/class/backlight/<backlight>/l3_dark_max
 120                 ===========  ================================================
 121
 122                 For ADP8870, <ambient light zone> can be:
 123
 124                 ===========  ================================================
 125                 Ambient      sysfs entry
 126                 light zone
 127                 ===========  ================================================
 128                 l1_daylight  /sys/class/backlight/<backlight>/l1_daylight_max
 129                 l2_bright    /sys/class/backlight/<backlight>/l2_bright_max
 130                 l3_office    /sys/class/backlight/<backlight>/l3_office_max
 131                 l4_indoor    /sys/class/backlight/<backlight>/l4_indoor_max
 132                 l5_dark      /sys/class/backlight/<backlight>/l5_dark_max
 133                 ===========  ================================================
 134
 135                 See also: /sys/class/backlight/<backlight>/ambient_light_zone.
 136
 137 What:           /sys/class/backlight/<backlight>/<ambient light zone>_dim
 138 Date:           Sep, 2009
 139 KernelVersion:  v2.6.32
 140 Contact:        device-drivers-devel@blackfin.uclinux.org
 141 Description:
 142                 Control the dim brightness for <ambient light zone>
 143                 on this <backlight>. Values are between 0 and 127, typically
 144                 set to 0. Full off when the backlight is disabled.
 145                 This file will also show the dim brightness level stored for
 146                 this <ambient light zone>.
 147
 148                 The <ambient light zone> is device-driver specific:
 149
 150                 For ADP5520 and ADP5501, <ambient light zone> can be:
 151
 152                 ===========  ================================================
 153                 Ambient      sysfs entry
 154                 light zone
 155                 ===========  ================================================
 156                 daylight     /sys/class/backlight/<backlight>/daylight_dim
 157                 office       /sys/class/backlight/<backlight>/office_dim
 158                 dark         /sys/class/backlight/<backlight>/dark_dim
 159                 ===========  ================================================
 160
 161                 For ADP8860, <ambient light zone> can be:
 162
 163                 ===========  ================================================
 164                 Ambient      sysfs entry
 165                 light zone
 166                 ===========  ================================================
 167                 l1_daylight  /sys/class/backlight/<backlight>/l1_daylight_dim
 168                 l2_office    /sys/class/backlight/<backlight>/l2_office_dim
 169                 l3_dark      /sys/class/backlight/<backlight>/l3_dark_dim
 170                 ===========  ================================================
 171
 172                 For ADP8870, <ambient light zone> can be:
 173
 174                 ===========  ================================================
 175                 Ambient      sysfs entry
 176                 light zone
 177                 ===========  ================================================
 178                 l1_daylight  /sys/class/backlight/<backlight>/l1_daylight_dim
 179                 l2_bright    /sys/class/backlight/<backlight>/l2_bright_dim
 180                 l3_office    /sys/class/backlight/<backlight>/l3_office_dim
 181                 l4_indoor    /sys/class/backlight/<backlight>/l4_indoor_dim
 182                 l5_dark      /sys/class/backlight/<backlight>/l5_dark_dim
 183                 ===========  ================================================
 184
 185                 See also: /sys/class/backlight/<backlight>/ambient_light_zone.
 186