There is a patch for NVIDIA driver 325.15 kernel 3.11 support, in the pastebin link in this thread, thanks to Milos_SD:

https://devtalk.nvidia.com/default/topic/549532/linux/linux-3-10-solved-3-11-solved-incompatibility-in-function-lsquo-nv_i2c_del_adapter-rsquo-error/2/

Now compiles cleanly, on kernel 3.11-rc4..

Robert Gadsdon.   August 6, 2013.