Reddit mentions of Linux-Treiber entwickeln.

I will just dump a few things I gathered:

Linux Device Drivers, Third Edition. Pretty old, still the standard.

If you understand German, check out Linuxtreiber entwickeln.

There used to be (recently closed) eudyptula challenge, for which you can search. There are some github repos with both the tasks and the trainees answers, like this one.

Also, check out /r/kernel/, kernel newbies and lwn (general). Less abut drivers, more about the low level stuff is this hobbyist git-book.

I'm sorry for being so unconcrete, as I haven't done a lot until now myself. If you just want to get a USB device running, maybe taking a look at PyUSB can help.

Edit: Here's how some folks managed to "hack the kinect". Very handy: If you have a working usb device + driver for windows, you can use wireshark +usbpcap to learn more about their inner workings.