I used “TX enable” to refer to the /RE and DE inputs on your transceiver. If you’ve verified that they toggle appropriately based on transmit and receive modes, then I guess you’re good. You didn’t list the gpio hog stuff from your device tree in the original post, so I assume you’re manually moving them around in your application?
The kernel docs have this and this and toradex has this
A pretty good discussion on the board regarding these kinds of things is here:
This code looks promising for testing.
Seems like you might have some sort of DE/RE issue going on or perhaps those lines aren’t tied into the serial driver device tree using things like uart-has-rtscts or rts-gpios? So maybe you’re never really in receive mode so the driver isn’t receiving? Or maybe you’re getting lucky with some sort of default rts/cts behavior and it’s enabling your receiver for a while and then not?