Nuttx is BSD, osmocom code is GPL. So, shall osmocom code for Nuttx be relicensed and only the application-repro contain GPL-code (probably no problem for drivers, but what about l1-code)? Or are we keeping GPL and keep in sync with upstream on our own (merging could get quite ugly if that diverges too much)?
I'd keep GPL for everything except custom modification of nuttx code (if even required).
There is no problem to have mixed BSD and GPL code in the same repository as long as the header of each file has clear mention. All our drivers (even for board / platforms / ...) will be new files and all of L1 as well.
Keeping in sync with upstream shouldn't be that hard if done periodically. I also assume they don't rewrite their whole API every month ...
Cheers,
Sylvain