As usual, some internal interfaces changed. Patches to follow...
Created attachment 197683 [details, diff]
Patch for the driver itself.
Created attachment 197684 [details, diff]
... and the patch for the ebuild.
NVIDIA and Gentoo, both do not support release candidate kernels.
Well, presumably this incompatibility will remain in 2.6.31-final, and I'm sure nvidia won't have a new release ready, so you could at least leave it open till then...
(At least the i2c change will certainly be in 2.6.31, as the struct members removed have been on the kernel feature removal list for a while.)
Why is it "RESOLVED WONTFIX" ??