shell script for configuring raspicomm rtc clock on startup

rpc-rtc-inst.sh

#! /bin/sh

# The content of the raspberry pi revision
# Content of the file /etc/init.d/rtc.sh
RTC_SCRIPT_HEADER="#! /bin/sh\n\n### BEGIN INIT INFO\n# Provides:          rtc\n# Required-Start:    $remote_fs $syslog\n# Required-Stop:     $local_fs\n# Default-Start:     2 3 4 5\n# Default-Stop:      0 1 6\n# Short-Description: Creates the real time clock i2c device when executed\n### END INIT INFO\n\n# Activate the real time clock\n"

RTC_SCRIPT_BODY_REVISION1="echo ds1307 0x68 > /sys/class/i2c-adapter/i2c-0/new_device"
RTC_SCRIPT_BODY_REVISION2="echo ds1307 0x68 > /sys/class/i2c-adapter/i2c-1/new_device"

RTC_SCRIPT_REVISION1=$RTC_SCRIPT_HEADER$RTC_SCRIPT_BODY_REVISION1
RTC_SCRIPT_REVISION2=$RTC_SCRIPT_HEADER$RTC_SCRIPT_BODY_REVISION2

revision=0
validinput=0

# Repeat the question 
while [ $validinput -eq 0 ]; do

  # Ask the user which revision of the raspberry pi he is using
	echo -n "Please specify the revision of the raspberry pi you are using [1,2]: "
	
	# read user input
	read revision
	
	if [ $revision -eq 1 ] ; then
		validinput=1	
	elif [ $revision -eq 2 ] ; then
		validinput=1
	fi

done

i2cMissing=0
# check if the i2c-devices exist before
if [ $revision -eq 1 ] ; then
	if [ ! -w "/sys/class/i2c-adapter/i2c-0/new_device" ] ; then
		echo "Error: /sys/class/i2c-adapter/i2c-0/new_device does not exist or not writable."
		i2cMissing=1
	fi
elif [ $revision -eq 2 ]; then
	if [ ! -w "/sys/clr,,pass/i2c-adapter/i2c-1/new_device" ] ; then
		echo "Error: /sys/class/i2c-adapter/i2c-1/new_device does not exist or not writeable."
		i2cMissing=1
	fi
fi

if [ $i2cMissing -eq 1 ] ; then	

	echo "It seems that your kernel is not configured for i2c device support, which is required for accessing the real time clock."

	enableI2C="n"
	echo -n "Do you want to enable i2c support? [y,n]: "
	read enableI2C

	if [ "$enableI2C" = "y" ]; then
		echo "trying to enable i2c support..."

		kernel=`uname -r`
		echo 'You using the kernel version' $kernel

		echo "loading i2c_bcm2708 module"
		modprobe i2c_bcm2708

		# check if i2c_bcm2708 is already added to /etc/modules
		installed=`cat /etc/modules | grep i2c_bcm2708 -c`
		if [ $installed = 0 ] ; then
			# if not, add i2c_bcm2708 to /etc/modules
			echo "adding i2c_bcm2708 module to startup"	
			echo "i2c_bcm2708" >> /etc/modules
		else
			echo "i2c_bcm2708 already added to /etc/modules"
		fi

	else
		echo "exiting..."
		exit			
	fi

fi


# Tell the user what we're doing
echo "deploying real time clock startup script /etc/init.d/rtc.sh for raspberry pi revision $revision"

# Depending on the revision deploy a startup script for the real time clock
if [ $revision -eq 1 ]; then
	echo $RTC_SCRIPT_REVISION1 > /etc/init.d/rtc.sh
else
	echo $RTC_SCRIPT_REVISION2 > /etc/init.d/rtc.sh
fi

echo Set /etc/init.d/rtc.sh to autostart

# Make the file executable
chmod +x /etc/init.d/rtc.sh

# Set the real time clock to be automatically started
update-rc.d rtc.sh defaults 80

# Execute the script right now to create the rtc i2c device
/etc/init.d/rtc.sh

exit 0