QNX4: How to use /dev/elousb0 ?

I need to develop driver for ELO touchscreen (2216 AccuTouch) connected via usb for QNX Windows (not Photon). I know what to do on QNX Windows side, this is no problem. I have also new usb driver, io-usb and devu-elo which provides /dev/elousb0. I would need to know how to employ the device to communicate with the touchscreen. I desperately tried to open the device, but nothing is coming automatically and if I try a command from smartset protocol (which the touchscreen should use), there is no response - no suprise as Input use generic interface (Input generic fd -d/dev/elousb0). If I can see the part of code of Input which use device for elo touchscreen, I would be able to manage it, I believe. But it seems to me this source code is not public. Any advice?