The 'RUN' directive is necessary to set /dev/bus/usb/PORT/ADDRESS permissions along with /dev/usb_endpointPORT.ADDRESS_epNN The script is as follows http://www.segger2.com/index.php?page=Thread&threadID=103

gistfile1.sh

BUS!="usb", ACTION!="add", SUBSYSTEM!=="usb_endpoint", GOTO="kcontrol_rules_end"
SUBSYSTEM=="usb_endpoint", ATTRS{idProduct}=="0101", ATTRS{idVendor}=="1366", MODE="0666", GROUP="usbusergroup", RUN+="/usr/local/bin/chk_jlink"
LABEL="kcontrol_rules_end"

gistfile2.sh

#!/bin/bash

GROUP="usbusergroup"

# Get the bus directory
BUS_DIR=`echo $DEVNAME | sed -e "s|/dev/usbdev\([0-9]*\).\([0-9]*\)_.*|\1 \2|" | awk '{printf "%03d/%03d",$1,$2}'`

FULL_PATH=/dev/bus/usb/$BUS_DIR

# Set permissions for FULL_PATH
chgrp -f --preserve-root $GROUP $FULL_PATH
chmod 0664 $FULL_PATH

exit 0