掌機 - Miyoo Mini - Stock - 設定屏背光


參考資訊：
https://github.com/jimgraygit/Onion

步驟如下： 

# echo 0 > /sys/devices/soc0/soc/1f003400.pwm/pwm/pwmchip0/pwm0/duty_cycle
# echo 100 > /sys/devices/soc0/soc/1f003400.pwm/pwm/pwmchip0/pwm0/duty_cycle