William Sowerbutts was the author of the Linux PowerMate driver, but his website was down for over a year, so I kept the code up to date and mirrored it here. Eventually the code got picked back up and is now in the official kernel, and his PowerMate Site is back up.
The PowerMate driver was incorporated in Linux Kernel 2.4.21 and released in RedHat 9. You will find also find it in Fedora natively, so you don't need to compile the kernel or compile modules.
These applications are not really OS level drivers, but programs to make your PowerMate work with existing applications.
brightenthat lets you control with the LED by turning and pushing. Derived from William R. Sowerbutts powermate-1.0, with the addition of brighten.c and a refactoring of some powermate_pulse_led and some definitions into findpowermate.c and findpowermate.h.
It's likely that the Griffin Powermate will already work with your kernel. If you have an old kernel or want to build it from scratch, you might need to read below.
Are you a KDE User? Perhaps you'd like to have PowerMate support in KDE. If so, please visit this feature request page: