#!/bin/bash

# This script is a helper for the following udev rules:
#
#   KERNEL=="ttyUSB*", PROGRAM="ttyUSB_id %p", SYMLINK+="tty-%c"
#   KERNEL=="ttyACM*", PROGRAM="ttyUSB_id %p", SYMLINK+="tty-%c"
#
# For use with these rules, copy or link this script to
# /lib/udev/ttyUSB_id or provide an absolute path in the `PROGRAM'
# parameter above.
#
#

[ -z "$1" ] \
    && echo -e "usage:   $0 <device-name>\nexample: $0 /class/tty/ttyUSB0" \
    && exit 1
TTYDEV=$1

# We support both the full class name as passed by udev, or just the
# tty name for command line convenience.
DIR1=/sys/$TTYDEV/device
DIR2=/sys/class/tty/$TTYDEV/device

if   [ -x $DIR1 ]; then cd $DIR1;
elif [ -x $DIR2 ]; then cd $DIR2;
else 
    echo "Can't find $DIR1 nor $DIR2" >&2
    exit 1
fi

# bus/hub-port physical tree address.
# Note that this is not unique if there are multiple interfaces per device!
# use one less .. to get the :<configuration>.<interface> tags too.
DEVTREE=$(basename $(readlink -f ../../))
# echo $@ DEVTREE=$DEVTREE >>/tmp/ttyUSB_id.log



# Follow symlink to usb device entry.
cd `pwd -P`
cd ../../


if   [ -f serial ]; then ID=`cat serial`;
elif [ ! -z "$DEVTREE" ]; then ID="$DEVTREE"
elif [ -f idProduct ]; then ID=`cat idVendor``cat idProduct`
else 
    echo "No serial, and can't use idVendor, idProduct" >&2
    exit 1
fi

echo $ID
exit 0