I'm using a 3.5 inch SPI screen on a Raspberry PI3.
I would like to know how is it possible to control the backlight value with a shell command.
I try to use the command
echo %s > /sys/class/backlight/rpi_backlight/brightness but the rpi_backlight folder doesn't exist.
The OS is Raspbian Strech HW : RPi 3 B+ Display : http://www.lcdwiki.com/3.5inch_RPi_Display