Extend device driver?

[Greg KH]

On Sat, Sep 10, 2016 at 04:41:34PM +0200, Pol Eyschen wrote:
> 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".

Please just use the hidraw userspace driver/library instead, that way
you don't have to unbind the kernel driver and everything should work
just fine without having to touch the kernel at all.

Hope this helps,

greg k-h