Kodi controller mapping question

So I have installed Kodi on my retropie, however the only form of input I have for the Pi is the iBuffalo SNES USB controller, which isn't natively supported in Kodi. I was wondering if anyone here knew how to map the controller to Kodi without needing a keyboard plugged into the pi? Is there something I can change in the Pi's SD card? any help appreciated, thank you.