raspberry pi reset usb code example
Example: reset usb port on rasbry pi
##--------------------
##--- Author: Pradeep Singh
##--- Blog: https://iotbytes.wordpress.com/
##--- Date: 1st Dec 2017
##--- Version: 1.0
##--- Python Ver: 2.7
##--- Description: This python code will reset a USB port connected to Raspberry Pi
##--------------------
import subprocess
import os
import fcntl
# Define "USB_DEV_NAME" variable based on the Device/Manufacturer name as shown
# in the output of the "lsusb" command on the linux shell
#
# For Example -
#
# I am using U.S. Robotics Analog USB Modem and want to reset it
# as shown in the following output my Modem is listed as "U.S. Robotics"
# hence I will use "U.S. Robotics" in the USB_DEV_NAME variable -
#
# pi@RaPi3:~ $ lsusb
# Bus 001 Device 004: ID 0baf:0303 U.S. Robotics <<<<<=========
# Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp. SMSC9512/9514 Fast Ethernet Adapter
# Bus 001 Device 002: ID 0424:9514 Standard Microsystems Corp.
# Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
# pi@RaPi3:~ $
USB_DEV_NAME = 'U.S. Robotics'
#===============================
# Reset Modem
#===============================
def reset_USB_Device():
# Same as _IO('U', 20) constant in the linux kernel.
CONST_USB_DEV_FS_RESET_CODE = ord('U') << (4*2) | 20
usb_dev_path = ""
# Based on 'lsusb' command, get the usb device path in the following format -
# /dev/bus/usb//
proc = subprocess.Popen(['lsusb'], stdout=subprocess.PIPE)
cmd_output = proc.communicate()[0]
usb_device_list = cmd_output.split('\n')
for device in usb_device_list:
if USB_DEV_NAME in device:
print device
usb_dev_details = device.split()
usb_bus = usb_dev_details[1]
usb_dev = usb_dev_details[3][:3]
usb_dev_path = '/dev/bus/usb/%s/%s' % (usb_bus, usb_dev)
try:
if usb_dev_path != "":
print "Trying to reset USB Device: " + usb_dev_path
device_file = os.open(usb_dev_path, os.O_WRONLY)
fcntl.ioctl(device_file, CONST_USB_DEV_FS_RESET_CODE, 0)
print "USB Device reset successful."
else:
print "Device not found."
except:
print "Failed to reset the USB Device."
finally:
try:
os.close(device_file)
except:
pass
#===============================
reset_USB_Device()