libusb

This site is the home for the libusb project. It aims to create a library for use by user level applications to access USB devices regardless of OS. (from libusb)

延伸閱讀：
libusb
libusb 的底層追蹤 (libusb thread support and the relation with kernel usbfs)
★ USB 驅動程式「libusb 函式庫」的介紹及其使用範例 ★
Snooping the USB Data Stream
Writing a Real Driver—In User Space