reset_usb.py

#!/usr/bin/env python

import os
import fcntl
import subprocess
import sys

# Equivalent of the _IO('U', 20) constant in the linux kernel.
USBDEVFS_RESET = ord('U') << (4*2) | 20

if __name__ == '__main__':
    proc = subprocess.Popen(['lsusb'], stdout=subprocess.PIPE)
    lines = proc.communicate()[0].split('\n')
    path = None
    for line in lines:
        if sys.argv[1] in line:
            parts = line.split()
            bus = parts[1]
            dev = parts[3][:3]
            path = '/dev/bus/usb/%s/%s' % (bus, dev)
            fd = os.open(path, os.O_WRONLY)
            try:
                fcntl.ioctl(fd, USBDEVFS_RESET, 0)
            finally:
                os.close(fd)
            break