pru: Add documentation and install scripts for running on the PRU

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

scripts/klipper-pru-start.sh

@@ -0,0 +1,36 @@
+#!/bin/sh
+# System startup script to start the PRU firmware
+
+### BEGIN INIT INFO
+# Provides:          klipper_pru
+# Required-Start:    $local_fs
+# Required-Stop:
+# Default-Start:     3 4 5
+# Default-Stop:      0 1 2 6
+# Short-Description: Klipper_PRU daemon
+# Description:       Starts the PRU for Klipper.
+### END INIT INFO
+
+PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
+DESC="klipper_pru startup"
+NAME="klipper_pru"
+
+. /lib/lsb/init-functions
+
+case "$1" in
+start)  log_daemon_msg "Starting klipper_pru" $NAME
+        # Enable ADC module
+        echo 'BB-ADC' > /sys/devices/platform/bone_capemgr/slots
+        # Start PRU firmware
+        if [ ! -c /dev/rpmsg_pru30 ]; then
+            rmmod -f pru_rproc
+            modprobe pru_rproc
+        fi
+        ;;
+stop|restart|reload|force-reload|status)
+        ;;
+*)      log_action_msg "Usage: /etc/init.d/klipper_pru {start|stop|status|restart|reload|force-reload}"
+        exit 2
+        ;;
+esac
+exit 0