|Version 1 (modified by 6 years ago) ( diff ),
Linux Backlight class digital display backlights
A digital display which has a backlight may have a Linux backlight driver which provides a sysfs API. Typically these are implemented via PWM signals allowing a variable brightness or a GPIO signal allowing a simple on/off.
Mapping A backlight driver to a PWM, GPIO, or other controller is done in the board support file or in the case of more modern kernels such as Ventana in the device-tree. See the backlight node in the gw54xx device-tree for example.
To list available backlight controllers:
To see current/available brightness values:
cat /sys/class/backlight/*/brightness # current brightness cat /sys/class/backlight/*/max_brightness # max brightness
To set brightness (to a value equal or less than max_brightness)
echo 0 > /sys/class/backlight/*/brightness # turn off backlight
Here are some other useful references from our wiki: