Hey @crsl,
The X1 pins 19 and 21 can be controlled via the Flex Timer Module. Here is the documentation for modifying the device tree : FTM for BSP 6.
A few things to keep in mind:
What OS you are using (I linked for downstream BSP 6) Is this correct?
You will also need to disable device tree nodes that are currently utilizing those pins.
You will need to utilize pin multiplexing for a new pinctrl group via to reference in your new FTM pwm nodes.
Looking at the source driver, it does look like the FTM driver adds the pwm chip to the pwm framework. So you should be able to see it in userspace. I have not validated this though.
-Eric