pwm err on Xavier l4t R32.3.1

I used pwm gpio pin 18, on l4t R32.2.3, it can be used by changed the pinmux config tegra19x-mb1-pinmux-p2888-0000-a04-p2822-0000-b01.cfg

pinmux.0x02434090 = 0x00000401; # soc_gpio12_ph0: rsvd0, pull-down, tristate-enable, input-enable, lpdr-disable

But when upgraded to l4t R32.3.1, nerther changing the pinmux config nor using the new tools Jetson‑IO, the pwm pin can’t be used normally.
Tested by Jetson.GPIO, it show

Traceback (most recent call last):
  File "/home/zhkj-robot/Documents/jetson-gpio/samples/", line 52, in <module>
  File "/home/zhkj-robot/Documents/jetson-gpio/samples/", line 40, in main
    p = GPIO.PWM(output_pin, 50)
  File "/home/zhkj-robot/Documents/jetson-gpio/lib/python/Jetson/GPIO/", line 597, in __init__
    self._reconfigure(frequency_hz, 50.0)
  File "/home/zhkj-robot/Documents/jetson-gpio/lib/python/Jetson/GPIO/", line 635, in _reconfigure
    _set_pwm_period(self._ch_info, self._period_ns)
  File "/home/zhkj-robot/Documents/jetson-gpio/lib/python/Jetson/GPIO/", line 245, in _set_pwm_period
IOError: [Errno 22] Invalid argument


Can you read the value of the register once the system is booted?
devmem2 0x02434090

Are you not seeing 0x00000401


Hello bbasu,

I can see the value 0x401

/dev/mem opened.
Memory mapped at address 0x7faba35000.
Value at address 0x2434090 (0x7faba35090): 0x401

The error is due to low PWM frequency request of 50Hz in the script.
To get it to work at 50Hz, please change the kernel dtb to add “pwm-minimum-frequency-hz = 10;” property under
pwm@32c0000 {

pwm-minimum-frequency-hz = <10>;

you can just change the frequency to 200Hz to make it work by changing script by changing line40 to
p = GPIO.PWM(output_pin, 200)