Re: USB driver
'firmware' and 'drivers' are not really the same. not sure if your after PC side
'drivers', or device side 'firmware', maybe both?
Firmware on the device should adhere to a standard protocol, if you want it to insert via a standard driver. Luckily, the various protocols are well documented.
Device only or OTG, picbridge,? Your device may require hosting capability.
Data streaming?, consider bandwidth, dropout, onboard buffering.
Power, port supplied?
You may want to concentrate on one of the classes, and become intimate with it.