Are you sure that you're not needing X drivers rather than kernel drivers? I did look into this a bit and it seemed that touchscreen is handled by
X drivers. If you have a particular kernel driver in mind let me know.
The thing is that I am not using X, but qws. I think the kernel driver is USB Tochscreen (CONFIG_TOUCHSCREEN_USB_COMPOSITE).
the output from lsusb is now :
Bus 001 Device 022: ID 17e9:401a Newnham Research
Bus 001 Device 021: ID 1ac7:0001
Bus 001 Device 020: ID 0ac8:c339 Z-Star Microelectronics Corp.
Bus 001 Device 019: ID 058f:6254 Alcor Micro Corp. USB Hub
Bus 001 Device 018: ID 050d:0234 Belkin Components F5U234 USB 2.0 4-Port Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
The second one is the usb touch device.