Cypress USB device from Windows to Linux

[Dave Smith]

I've got a Cypress-based USB device that has been solely used with Windows in 
the past. Now I want to make that device work under Linux. I imagine this 
means I'll have to do some hacking to create a driver (but maybe not). This is 
not a "standard" device like a keyboard, hard drive, or webcam. It has its 
own, in-house-developed command set for interacting with the device. When I 
connect the device to my Arch box, this appears in /var/log/messages.log:

  kernel: usb 1-1: new high speed USB device using ehci_hcd and address 2
  kernel: usb 1-1: config 1 interface 0 altsetting 0 bulk endpoint 0x81 has 
invalid maxpacket 64
  kernel: usb 1-1: configuration #1 chosen from 1 choice

I don't really know where to get started. Can anyone recommend a starting 
point? Books? Other resources? General advice?

Thanks!

--Dave