Trouble detecting touchscreen

I have a hitaci visionplate webpad, it came with
2.4 "midori" linux and I'm trying to get it to work with a recent
debian distro. I haven't been able to get the touchscreen to work.

lspci doesn't report anything that looks like a touchscreen
When the system starts up there's no dev that seems to correspond to the
touchscreen. I think the ts is a mk712 (because the old system came with a
mk712 driver and no other touchscreen drivers) but I'm not really sure
(because the driver appears not to be used). If I do a modprobe mk712
it creates /dev/input/ts0 and /dev/input/mouse0, but they appear not to
be actually doing anything.

Any suggestions?