FM Radio

[drpi]

you can push two(or many more) channels(stereo) of digital audio in the i2c stream along with control and other data

This is a non-sense. I2C can't transport digital audio.

In theory there's enough bandwidth even on a standard mode bus for compressed audio, so it could be done. In practice so far as I know none of the FM radio chips don't support that, and there's no standard I've heard of for it. If either exist I'd be interested to learn more. I suspect there's some confusion between i2c which we're talking about here, and i2s which is commonly used for stereo audio.

I2C standard speed is 100kb/s. Not enough throughput for audio, even compressed (100kb/s is raw throughput, effective throughput is much less).
Fast speed is 400kb/s. Achieving 128kb/s compressed audio might be possible in theory.
But, keep in mind the bus is shared with other chips, and you have to find a way to do hard real time communication from user/kernel app.