switcher

#!/bin/sh

# This script allows selects which device (host or target) the micro SD card is
# connected to

# assumptions:
# 1. this script is running on a rpi3 model b and that the mux select pin is attached to gpio 23
# 2. target is device 1, host is device 2
# 3. host plug is plugged into ugen0.4

toggle_pin=23
host_select=0
target_select=1
host_device=0.4

usage()
{
	echo "usage: switcher [-h|-t]"
	echo "-h	Attach to host"
	echo "-t	Attach to target"
	exit 1
}

setup_gpio()
{
	gpioctl -c $toggle_pin OUT
}

configure_host_usb()
{
	usbconfig -d "${host_device}" power_off
	usbconfig -d "${host_device}" power_on
}

host()
{
	echo "attaching to host"
	setup_gpio
	gpioctl $toggle_pin $host_select
	configure_host_usb
}

target()
{
	echo "attaching to target"
	setup_gpio
	gpioctl $toggle_pin $target_select
	configure_host_usb
	# Ideally the target device is connected to a controllable power source
	# and set to reboot on a power cycle. During testing no such 
	# power source was available so:
	echo "please power cycle target"
}

if [ $# -ne 1 ];
then
	usage
fi

case $1 in
	"-h") host;;
	"-t") target;;
	*) usage;;
esac

exit 1