QMK kernel module - connect your keyboard switches directly to the gpio of your raspberry pi, no keyboard controller needed!
I found this while looking for ways to make cyberdecks smaller - a keyboard controller board can be just as big as a pi zero, wasting much needed space. The QMK kernel module allows the raspberry pi to be used as a keyboard controller, while still running a full os.
https://github.com/qmk/qmk_kernel_moduleOpen linkView original on feddit.de