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