FAN control on Rock 3a

[BARS]

Hi.

I need to run FAN control on the Rock 3a board. But i don't have rk3568-pwm8-m0-fan.dtbo in boot/dtb-6.0.10-rk35xx/rockchip/overlay. I copied rk3568-pwm8-m0-fan.dtbo from 4.19.193-67-rockchip folder. This script applied on the start:

Applying kernel provided DT overlay rk3568-pwm8-m0-fan.dtbo
2698 bytes read in 52 ms (49.8 KiB/s)

 

The /sys/devices/platform/fe6f0000.pwm folder is being created. I apllyed this commands:

root@rock-3a:~# echo 0 > /sys/devices/platform/fe*.pwm/pwm/pwmchip*/export
root@rock-3a:~# echo 10000 > /sys/devices/platform/fe*.pwm/pwm/pwmchip*/pwm0/period
root@rock-3a:~# echo 5000 > /sys/devices/platform/fe*.pwm/pwm/pwmchip*/pwm0/duty_cycle
root@rock-3a:~# echo normal > /sys/devices/platform/fe*.pwm/pwm/pwmchip*/pwm0/polarity
root@rock-3a:~# echo 1 > /sys/devices/platform/fe*.pwm/pwm/pwmchip*/pwm0/enable # Turn on fan
root@rock-3a:~# echo 0 > /sys/devices/platform/fe*.pwm/pwm/pwmchip*/pwm0/enable # Turn off fan

But there is no PWM on the FAN connector. I see 800 mV DC voltage on the PWM pinin the FAN connector. How I can run the FAN PWM?

[BARS]

I'm not apllyed command

root@rock-3a:~# echo 0 > /sys/devices/platform/fe*.pwm/pwm/pwmchip*/pwm0/enable # Turn off fan

 

only 

root@rock-3a:~# echo 1 > /sys/devices/platform/fe*.pwm/pwm/pwmchip*/pwm0/enable # Turn on fan

Edited March 19, 2023 by BARS