Building in-tree kernel module

[KestutisMa]

• PYNQ version (e.g. v2.6): v3.0.1
• Board name (e.g. Pynq-Z2): Pynq-Z2
• Pull request type (bug fix / new feature): Question/Feature

Amazing work, thanks for your time on this project!
I am trying to build in-tree kernel module (SPI LCD). I see there are Pynq bsp recipies, and read that these are the way of building modules in Peta Linux, but I'm doing this for first time. I've spent many days of trying to figure out things myself. Also, I didn't got response in Pynq forums (maybe no many kernel devs there) for 3 months so asking here.

Question: What is recommended general way of building in-tree kernel module? Is it possible to build it without rebuilding whole system image?