I haven't had a lot of time to dedicate to this project recently. A few months ago, however, I finished some HDL and C to get the SuperAudioBoard working with my Spartan 6 Microboard FPGA dev kit. I just never got around to actually putting the code up until now.
If you check the github repo, you'll see a new folder called S6MicroBoard_PoC. This has all the HDL and C needed to get the SuperAudioBoard working with this particular FPGA board, along with instructions to get started using Xilinx ISE 14.7 and the Xilinx SDK.
The files include some pretty simple I2C and I2S interfaces that I built from scratch, and the overall FPGA image also includes a microblaze microprocessor system core to handle initializing the CS4272 and send and receive audio data.
The I2S and I2C modules are meant to interface with the microblaze MCS interface bus, which is a very simple bus, so these modules should be easy to extend to other bus types for use in other FPGAs or applications.
The code is pretty specific to the Xilinx platform, but could probably be easily modified to work on any other soft core.