| What: /sys/class/backlight/<backlight>/scale |
| Date: July 2019 |
| KernelVersion: 5.4 |
| Contact: Daniel Thompson <daniel.thompson@linaro.org> |
| Description: |
| Description of the scale of the brightness curve. |
| |
| The human eye senses brightness approximately logarithmically, |
| hence linear changes in brightness are perceived as being |
| non-linear. To achieve a linear perception of brightness changes |
| controls like sliders need to apply a logarithmic mapping for |
| backlights with a linear brightness curve. |
| |
| Possible values of the attribute are: |
| |
| unknown |
| The scale of the brightness curve is unknown. |
| |
| linear |
| The brightness changes linearly with each step. Brightness |
| controls should apply a logarithmic mapping for a linear |
| perception. |
| |
| non-linear |
| The brightness changes non-linearly with each step. Brightness |
| controls should use a linear mapping for a linear perception. |
| |
| What: /sys/class/backlight/<backlight>/ambient_light_level |
| Date: Apr, 2010 |
| KernelVersion: v2.6.35 |
| Contact: Michael Hennerich <michael.hennerich@analog.com> |
| Description: |
| (RO) Get conversion value of the light sensor. |
| |
| The value is automatically updated every 80 ms when the |
| light sensor is enabled. |
| |
| The value range is device-driver specific: |
| |
| For ADP8870: |
| |
| It returns integer between 0 (dark) and 8000 (max ambient |
| brightness). |
| |
| For ADP8860: |
| |
| It returns a 13-bits integer. |
| |
| What: /sys/class/backlight/<backlight>/ambient_light_zone |
| Date: Apr, 2010 |
| KernelVersion: v2.6.35 |
| Contact: Michael Hennerich <michael.hennerich@analog.com>, |
| device-drivers-devel@blackfin.uclinux.org |
| |
| Description: |
| (RW) Read or write the specific brightness level at which the |
| backlight operates. |
| |
| The value meaning is device-driver specific: |
| |
| For ADP8860: |
| |
| == ========================== |
| 0 Off: Backlight set to 0 mA |
| 1 Level 1: daylight |
| 2 Level 2: bright |
| 3 Level 3: dark |
| == ========================== |
| |
| For ADP8870: |
| |
| == ========================== |
| 0 Off: Backlight set to 0 mA |
| 1 Level 1: daylight |
| 2 Level 2: bright |
| 3 Level 3: office |
| 4 Level 4: indoor |
| 5 Level 5: dark |
| == ========================== |
| |
| Writing 0 returns to normal/automatic ambient light level |
| operation. |
| |
| It can be enabled by writing the value stored in |
| /sys/class/backlight/<backlight>/max_brightness to |
| /sys/class/backlight/<backlight>/brightness. |