Pen Controller specs needed

[Chris Schumann <whizkid@home.dwave.net>]

Since IBM is never going to write a pen driver for my ThinkPad 750P for
Windows 95 nor Windows NT, I've decided to write one myself. (Perhaps the
knowledge learned will help someone else write a Linux or FreeBSD driver
as well.)

Where can I get information on the interface logic? I imagine I'll need 
things like the part number and manufacturer. Once I have those, I can 
get spec. sheets with register maps and such. (I do know that I can 
change the address and IRQ of the controller even under Win95, but no 
driver I have will use it.)

I plan to make the device appear as another mouse for now, so the pen 
functionality (handwriting, gestures and such) will not be present.

Thanks much in advance,
Chris Schumann