Bluetooth joypad-watching daemon for RetroPie

jsdaemon.sh

#!/bin/bash
# For my RetroPie-based Game Frame
# When a bluetooth controller is connected, will turn on the screen, put the processor into 
# "performance" mode, and start EmulationStation
# When any controller presses L+R+Start+Select, the reverse will occur:
# ES is killed, the processor is put into "ondemand" mode, HDMI is turned off, and all BT 
# devices are disconnected.

watch_pad() {
	DEV=/dev/input/$1
	CONNECT="$2"
	DISCONNECT="$3"
	SIG_POWER="$4"
	CONNECT_STATE="$(test -e /dev/input/$1 && echo "yes" || echo "no")"
	while true; do
		SKIP=4
		if [[ ! -e /dev/input/$1 ]]; then
			sleep 5
		else
			if [[ "$CONNECT_STATE" == "no" ]]; then
				$CONNECT $DEV
			fi
			CONNECT_STATE="yes"
			jstest --event /dev/input/$1 2>/dev/null | 
			while read event; do 
				if [[ $SKIP -eq 0 ]]; then
					event=$(echo "$event" | cut -d : -f 2)
					type=$(echo "$event" | cut -d ',' -f 1 | cut -d \  -f 3)
					if [[ $type -ge 128 ]]; then
						type=$(expr $type - 128)
					fi
					number=$(echo "$event" | cut -d ',' -f 3 | cut -d \  -f 3)

					state=$(echo "$event" | cut -d ',' -f 4 | cut -d \  -f 3)
					eval "T${type}_N${number}=$state"
					if [[ $T1_N6 == 1 && $T1_N7 == 1 && $T1_N10 == 1 && $T1_N11 == 1 ]]; then 
						$SIG_POWER $DEV
					fi
				else
					SKIP=$(expr $SKIP - 1)
				fi
			done
			CONNECT_STATE="no"
			$DISCONNECT $DEV
		fi
	done
	trap 
}

PIDS=
watch_pad js0 'retropie-wake.sh' 'echo disconnect' 'retropie-suspend.sh' & PIDS="$PIDS $!"
watch_pad js1 'retropie-wake.sh' 'echo disconnect' 'retropie-suspend.sh' & PIDS="$PIDS $!"
watch_pad js2 'retropie-wake.sh' 'echo disconnect' 'retropie-suspend.sh' & PIDS="$PIDS $!"
watch_pad js3 'retropie-wake.sh' 'echo disconnect' 'retropie-suspend.sh' & PIDS="$PIDS $!"

kill_jobs() {
	for pid in $PIDS; do
		CHILDREN=$(ps -opid,ppid -A | grep -E '[0-9]+ '"$pid" | grep -Eo '^[0-9]+')
		echo "killing $CHILDREN $pid"
		kill -9 $CHILDREN > /dev/null
		kill -9 $pid > /dev/null
	done
	sleep 5
}
trap kill_jobs EXIT

for pid in $PIDS; do
	wait $pid >/dev/null
done

retropie-suspend.sh

#!/bin/bash
tv_is_on() {
	if [[ -n "$(tvservice -s | grep '0x120002')" ]]; then
		return 1
	else
		return 0
	fi
}
any_bt_connected() {
	if [[ -n "$(hidd --list)" ]]; then
		return 0
	else
		return 1
	fi
}
echo "ondemand" | sudo tee /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor >/dev/null
if ps -C emulationstation > /dev/null; then
	killall emulationstation
fi
if tv_is_on; then
	tvservice -o
fi
if any_bt_connected; then
	sudo hciconfig hci0 down
	sleep 1
	sudo hciconfig hci0 up
	sudo hciconfig hci0 pscan
fi

retropie-wake.sh

#!/bin/bash
tv_is_off() {
	if [[ -z "$(tvservice -s | grep '0x120002')" ]]; then
		return 1
	else
		return 0
	fi
}
if tv_is_off; then
	tvservice -p
	sleep 1
	fbset -accel false
	fbset -accel true
fi
echo "performance" | sudo tee /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor >/dev/null
if ! ps -C emulationstation > /dev/null 2>&1; then
	echo "Starting EmulationStation"
	emulationstation &
fi