Extend device driver?

Hi everyone,

I want to implement some custom functions of my mouse (Madcatz RAT5) in 
Linux, e.g custom DPI-values. As this requires writing over USB to the 
firmware of the mouse I was thinking of writing a module to accomplish 
this. However I don't want to reimplement a whole mouse-driver,so I 
wanted to ask if there is a possibility of binding the device to 2 
modules or having my module extend usbhid, so that my module would only 
be used to perform these custom operations while usbhid stays in charge 
of the whole "mouse business".


Thanks

Pol