Hello, Stefan!
Actually, I doesn't real Linux C programmer - I just passed by. :)
So, I just tried to get into this area, but get very distracted by wretchedness and inconvenience of Linux development tools. I don't think there's will be next time. :) I just "threw patch away", hoping that this programmer widely enough available and somebody, having proper skills, finishes it. Seems to be, my thoughts was wrong, but till now I don't be sad.
Now I surprised! Thank you for your precious time to finish this patch, Stefan!
I marked them as untested because I think that my one working quick dirty patch is not an reliable proof of testing.
It doesn't need any enable routine - it has no logic, no triggers/relay - just resistors and buffer.