#!/usr/bin/env python2

import fcntl
import os
import subprocess
import sys
import time

if not sys.platform.startswith("linux"):
    print >>sys.stderr, "Sorry, this tool requires Linux"
    sys.exit(1)

try:
    search_usb_id = sys.argv[1].lower()
except IndexError:
    print >>sys.stderr, "Usage: %s vendorid:devid" % sys.argv[0]
    print >>sys.stderr, "\nThis tool will reset all USB devices with the given ID (eg 1f4d:a803)"
    sys.exit(1)


USBDEVFS_RESET = 21780

os.umask(0007)

p = subprocess.Popen(["lsusb"], stdout=subprocess.PIPE)
for line in p.stdout:
    line = line.split()
    usb_id = line[5].lower()
    if usb_id != search_usb_id:
        continue
    bus = line[1]
    dev = line[3].replace(":", "")

    filename = "/dev/bus/usb/%s/%s" % (bus, dev)
    print "Resetting", filename, "...",
    sys.stdout.flush()
    fd = os.open(filename, os.O_WRONLY)
    ret = fcntl.ioctl(fd, USBDEVFS_RESET, 0)
    if ret < 0:
        print >>sys.stderr, "\nError in ioctl:", ret
        sys.exit(1)
    os.close(fd)
    time.sleep(1)
    print "done"