[AnthonyMouse]

> If you want to avoid licensing the other versions of your driver under GPLv2, you'd have to carefully avoid copying any code from the main kernel into your translation layer (rewriting any helper functions you end up using), and even then there's the idea of API copyright to contend with.

Isn't the point supposed to be to not have other versions of your driver, so you can use the same one on every platform?

[comex]

By "other versions" I mean the codebase used for a given non-Linux platform, which would (hypothetically) include most of the Linux driver's code plus a translation layer from Linux APIs to that platform's.

[AnthonyMouse]

The translation layer isn't where the interesting bits are. The parts hardware companies want to keep secret are the hardware-specific parts, not the OS-specific parts. It might even help them to open source the translation layers because then others could potentially use them and shoulder some of the maintenance cost.

I can't speak to the legal status of GPL drivers for Windows, but several seem to exist already (e.g. Windows ext4 driver), and if they were actually worried about it they could always get explicit permission from the copyright holders of the relevant code. Either they say yes and you're fine or they say no you know what pieces of code to replace.