screen brightness (backlight pwm)

[hal80]

Do we have a chance of implementing a backlight brightness control via PWM modulation, like this one here: https://ozzmaker.com/forums/topic/screen-brightness/

Tests done so far: I have the official V2 kit OzzMaker PiScreen 3.5' touch-display. I followed the steps in the link above and get to this point:

root@zynthian:~/pi-blaster# sudo ./pi-blaster 22
Using hardware:                   PWM
Number of channels:                 1
PWM frequency:                 100 Hz
PWM steps:                       1000
Maximum period (100  %):      10000us
Minimum period (0.100%):         10us
pi-blaster: Page 0 not present (pfn 0xa1000000000624c0)
root@zynthian:~/pi-blaster# 

Screen brightness doesn't change with the given commands (echo "0=.5" > /dev/pi-blaster, echo "0=1" > /dev/pi-blaster), it just stays at max. brightness.