I think 4cc it bit useless with RGB stuff (or maybe i just don't understand 4cc). For instance i think we want uniq different id for RGB555, RGB565,RGBX8888, RGBA8888, BGRA8888 ... it seems 4cc just says rgb and than rely on additional informations for color order or components size.
Yes - grep "fourcc" include/linux/videodev2.h
plus see the docs - I think its sufficient for pretty much all of it we would end up needing except maybe a few texture formats like S3TC (which are of course 4CC codes too)
Alan