extra/usb_serial/add_usb_serial_id

#!/bin/sh -e
#
# Copyright 2016 The ChromiumOS Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
#
# Add a USB VID:PID device ID to the usbserial list of handled devices

if [ $# -ne 2 ]; then
    echo ""
    echo "Usage: $0 <VID> <PID>"
    echo ""
    echo "Add a USB VID:PID device identification pair to the list of devices"
    echo "that usbserial will recognize.  This script ensures that a device is"
    echo "not added more than once."
    echo ""
    exit 1
fi

#
# Firts ensure that the usbserial module is loaded.  This is required as there
# may be no other USB serial adaptor connected yet.
#
modprobe usbserial

device_id="$1 $2"
file="/sys/bus/usb-serial/drivers/generic/new_id"

#
# Only add the device ID pair if it isn't already in the ID list.
#
grep -q "$device_id" $file || echo $device_id > $file