Wii U GamePad
Official Controller for the Wii U
Steam Input support
No
Linux Kernel Support
No
Ongoing projects
A list of projects and drivers that try to make the Wii U controller work on Linux.
libdrc
There has been efforts of adding by the libdrc team of add their hid-wiiu-drc to the Linux Kernel.
Linux WiiU
Is a Linux distro that can be used on the Wii U machine. This seams to have a working hid-wiiu-drc
But the efforts to add it to the kernel seams to have been stalled.