| David Brazdil | 0f672f6 | 2019-12-10 10:32:29 +0000 | [diff] [blame] | 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. |
| Olivier Deprez | 157378f | 2022-04-04 15:47:50 +0200 | [diff] [blame^] | 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. |