driver using device trees, irqs, powerpc

[Alan Bennett]

Need help adding new driver to supports a custom FPGA.  Is there a
good driver that anyone would recommend I can look at that is fully
functional, works with 2.6.23 (powerpc style) and is described within
a device tree?

Bonus points:
  uses freescale interrupts (timers/irq's from mpc 82xx/etc...)
  isn't enet / cpm_uart (I've already looked at these)

-Alan