I've written a touch-screen controller driver for the Linux kernel. It seems to work.

BTW:
> The CE has P/N 80000113-057 rev e04.
> The CPLD reports revision number 0x20a

I haven't been able to determine the role of the PIRQ bit. When I clear the bit, the touch interrupt bit goes low. However, if I leave PIRQ high, the touch controller appears to work correctly.

The documentation states that the touch interrupt pin has to be driven for correct operation of the touch controller. But the version of the datasheet that I've found makes no mention of this.