qmk_kernel_module VS nanoCH32V203

With QMK Kernel Module one could skip MCU altogether and just use one Linux SBC. But sadly that module is not maintained.

Currently I'm trying to get the qmk linux kernal module up and working properly. Is there any recent projects or documentation on using a rpi0 for keyboards? I could write out a device tree program, but that would be a pretty big headache.

My ideal scenario here would be to just use a pi 0 as the controller fully, but from what I can tell, the only real options for that are attempt to extend/iterate the kernel module that u/jackhumbert wrote for fun as it isn't feature complete qmk or write something in circuitpython or similar. Given the choice I'd rather not reinvent the wheel and just have full fat qmk on tap.

If you are willing to try r/RISCV ones, then nanoCH32V203 (with two Full-Speed interfaces) and nanoCH32V305 (with one Full-Speed and one High-Speed interface) might be enough.

There are dual USB r/RISCV boards with GPIO pins exposed, like nanoCH32V203 and nanoCH32V305.

Another alternative is to use dual USB MCU board like nanoCH32V203 as USB CDC relay.

RISC-V boards cost $3-$6 depending if you want high speed USB or full speed one.

Their earlier boards like nanoCH32V203 and nanoCH32V305 were more user friendly, one could flash those via USB without WCH-Link.

Muse Lab has MCU boards like nanoCH32V203 and nanoCH32V305.

The same form factor as nanoCH32V203, but with more RAM and storage, also one of USB interfaces is high speed and SDIO is native this time. Comparable to CH32V307 boards, but lacks ethernet port.

Speaking of hardware there is very nice $3 RISC-V board that would fit well USB to USB converter use case. No keyboard firmware is ported to it yet.