comparison resources/shutdown_switch.sh @ 274:cf98c06c72fd prerelease

merge

+#!/bin/bash
+#
+# shutdown_switch.sh: script for gracefully halting the BeagleBone Black
+# when an onboard button is pressed. 
+#
+# (c) 2016 Andrew McPherson, C4DM, QMUL
+# Developed for Bela: http://bela.io
+
+
+# Prepare P9.27 as input (will be configured with pullup)
+# via BB-BONE-PRU-BELA overlay
+
+BUTTON_PIN=115
+
+echo $BUTTON_PIN > /sys/class/gpio/export
+echo in > /sys/class/gpio/gpio"$BUTTON_PIN"/direction
+
+if [ ! -r /sys/class/gpio/gpio"$BUTTON_PIN"/value ]
+then
+	echo "$(basename $0): Unable to read GPIO pin $BUTTON_PIN for shutdown button."
+	exit
+fi
+
+# First, wait for pin to go high. If it starts at 0, that's more
+# likely that the GPIO is not set correctly, so do not treat this
+# as a button press
+
+while [ $(cat /sys/class/gpio/gpio"$BUTTON_PIN"/value) -ne 1 ]; do
+	# Keep checking pin is readable in case it gets unexported
+	if [ ! -r /sys/class/gpio/gpio"$BUTTON_PIN"/value ]
+	then
+		echo "$(basename $0): Unable to read GPIO pin $BUTTON_PIN for shutdown button."
+		exit
+	fi
+	sleep 0.5
+done
+
+# Now for button press. Make sure the button is held at least
+# 1 second before shutting down
+
+PRESS_COUNT=0
+
+while true; do
+  # Keep checking pin is readable in case it gets unexported
+  if [ ! -r /sys/class/gpio/gpio"$BUTTON_PIN"/value ]
+  then
+    echo "$(basename $0): Unable to read GPIO pin $BUTTON_PIN for shutdown button."
+	exit
+  fi
+	
+  # Button pressed? (pressed = low)
+  if [ $(cat /sys/class/gpio/gpio"$BUTTON_PIN"/value) -eq 0 ]
+  then
+    PRESS_COUNT=$((PRESS_COUNT+1))
+	if [ "$PRESS_COUNT" -ge 4 ]
+	then
+    	echo "$(basename $0): Shutdown button pressed. Halting system..."
+		halt
+		exit 1
+	fi
+  else
+    PRESS_COUNT=0
+  fi
+  sleep 0.5
+done