#!/bin/sh

# $Id: pwr-switch 122491 2022-06-02 13:30:06Z sluijtma $
# $URL: https://svn.uvt.nl/its-unix/systems/hastur/usr/local/sbin/pwr-switch $

INIT_PIN(){
	# the PWR-SWITCH is connected to GPIO 15 and the presceding ground pin
	# reference page https://pinout.xyz/pinout/
	[ -d /sys/class/gpio/gpio15 ] && echo "Pin already initialised" && exit 0
	echo 15 > /sys/class/gpio/export
	echo out > /sys/class/gpio/gpio15/direction
}

DEINIT_PIN(){
	[ -d /sys/class/gpio/gpio15 ] || echo "Pin not initialised" && exit 0
	echo 15 > /sys/class/gpio/unexport
}

PIN_STATUS(){
	if [ -d /sys/class/gpio/gpio15 ] ; then
		echo "pin status: Pin initialised"
	else
		echo "pin status: Pin not initialised"
	fi
}

SWITCH_ON(){
	# initialise pin before doing anything
	[ -d /sys/class/gpio/gpio15 ] || INIT_PIN
	echo 1 > /sys/class/gpio/gpio15/value
}

SWITCH_OFF(){
	# initialise pin before doing anything
	[ -d /sys/class/gpio/gpio15 ] || INIT_PIN
	echo 0 > /sys/class/gpio/gpio15/value
}

TOGGLE_SWITCH(){
	# initialise pin before doing anything
	[ -d /sys/class/gpio/gpio15 ] || INIT_PIN
	case $(cat /sys/class/gpio/gpio15/value) in
		1) SWITCH_OFF;;
		0) SWITCH_ON;;
	esac
}

USAGE(){
	cat >&2 <<EOF
Usage: pwr-switch <on|off|init|deinit|help>
	on: send on signal
	off: send off signal
	init: initialise pin
	deinit: deinitialise pin
	status: show pin initialisation state
	toggle: toggle on/off signal
EOF
}

case $1 in
	on) SWITCH_ON;;
	off) SWITCH_OFF;;
	init) INIT_PIN;;
	deinit) DEINIT_PIN;;
	status) PIN_STATUS;;
	toggle) TOGGLE_SWITCH;;
	*) USAGE;;
esac