Here is a slightly updated version of Chen-Yu's backlight
patches, also adding support for the backlight found on A13
based q8 tablets.
If i compile your dtsi with (obviously) pwm support enable , backlight switch off after kernel start,
if i disable pwm in menuconfig,it stay on, all seem correct (pwm on PB2 in original script.bin),
but there is somewhere a bug in pwm or dtsi description of backlight.
Silviop