Hi!
I've been working on a driver for the new 390 channels RME MADI FX.
For those who are interested, I've made the source available here:
https://github.com/adiknoth/madifx
As mentioned there, I only had remote access, so not all possible hardware configurations have been tested. This might change next year, until then, consider everything as "coincidentally working" ;)
Most importantly, the userspace API isn't stable, yet, since we still have to develop new tools for metering and mixer adjustments. If we exclude this API (the ioctls) for now, it is moderately safe to go mainline, though we definitely lack decent test coverage.
ALSA devs: Feel free to demand any changes that are required for mainline inclusion. The github repo is meant to serve as an incubator from which we'll eventually derive the final kernel patch.
Cheers