Hardware register layouts, bit meanings, and constants are facts about the hardware, not a creative expression by Linux developers. So you can look at Linux code to reverse-engineer and understand how the hardware works, even if you don't release your code under the GPL. But of course if you can look at non-GPL code, it's always safer.
The best approach to reverse engineering when in doubt about copyright is the "clean-room" approach: https://en.wikipedia.org/wiki/Clean-room_design However, this requires a minimum of two people working on the project. I think RPI4 support (especially with ethernet) would be a great addition to NuttX. But given my previous experience in embedded reverse engineering - it's a waste of time. Projects like these are impossible to estimate and always take more time (and nerves) than we would like (and there is no guarantee that it'll succeed). czw., 28 sie 2025 o 21:46 Michał Łyszczek <michal.lyszc...@bofc.pl> napisał(a): > On 2025-08-28 16:21:55, Alan C. Assis wrote: > > We cannot look at the Linux source code, because it is GPL license, but > we > > can look at the FreeBSD code: > https://wiki.freebsd.org/arm/Raspberry%20Pi > > Like who's even gonna prove you've looked at GPL code when implementing rpi > support? If you don't copy paste code, but learn protocol and what > register to > write in what order noone is gonna do anything. With that logic in mind, > my last > project must be turned into GPL because I peeked into Linux kernel how they > drive some peripheral. You must have read some GPL code in your life. You > probably even wrote something *very* similar. Does that make code GPL? > > If I was implementing something in Linux for rpi4 does that disqualify me > from contributing? > > Don't blatantly copy-paste code from Linux Kernel, but learn from it and > implement with your own way. You don't copy code, you learn from it. This > is > not copywritable. > > If you reverse engineer some secret nvidia gpu, yes, you want to be crazy > extra > and just reject anyone that had anything to do with nvidia. But this is > open source and free code. And you are doing open source and free software. > I think it's 100% safe to look at Linux to leare how things work - not to > steal > the code. >
