Forward port for 1.13 was done by Marko Saukko, all I did was a tweak for 1.14 and corrected some paths here and there to match dss changes in more recent kernels, packaging etc. For kernel driver, I bluntly removed dependency to dss bits that appeared to be not upstreamed. I'm not sure at all it's done right, or if it's enough but at least it's been usable for 2D, and the few GLES tests I've done, did work.
So, we have usable driver, which is somewhat faster and more featurefull than the plain fbdev to use until someone comes up with a better one. Unfortunately I don't possess the skills to do that.