Is it possible to change the polarity of the PWM controller at the hardware level?

Robotics & Edge Computing Jetson Systems Jetson AGX Orin
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1

I’m using a Jetson AGX Orin DevKit Jetpack 7.2 and need to output two trigger signals with different frequencies. I’ve already activated the PWM1 and PWM5 controllers on pins 15 and 18, configured the parents clock to my parameters, and synchronized between signals, but I ran into a problem where the low-frequency signal edge (1) corresponds to 0 on the high-frequency signal, and I need a simultaneous trigger. I tried changing the polarity of one PWM5, including in the file “/sys/class/pwm/pwmchip2/pwm0/polarity”, but nothing worked. The Orin driver file “drivers/pwm/pwm-tegra.c” also doesn’t have a polarity bit. Is this even possible?

Or is it possible to change the starting state from 0 to 1 through the .dtbo overlay setting?

3

This is not supported by the current Tegra PWM controller implementation on Jetson AGX Orin.
The pwm-tegra driver does not support inverted polarity, and the controller register interface used by the driver does not expose a polarity bit.
Therefore, changing sysfs polarity or adding polarity in DT overlay will not invert the output, and there is no DT setting to start the PWM from logic high.
If simultaneous active edges are required, this will need to be solved externally or with a different signal source/controller.