#!/bin/bash
#
# Simple script implementing a temperature dependent fan speed control
#
# Version 0.61
#
# Usage: fancontrol [CONFIGFILE]
#
# Dependencies:
#   bash, awk, egrep, sed, lm_sensors :)
#
# Please send any questions, comments or success stories to
# marius.reiner@hdev.de
# Thanks!
#
# The latest version of this script is available at:
# http://www.hdev.de/fancontrol/fancontrol.html
# or in the CVS version of lm_sensors
#
# For configuration instructions and warnings please see fancontrol.txt, which
# can be found in the doc/ directory or at the website mentioned above.
#
#
#    Copyright 2003 Marius Reiner <marius.reiner@hdev.de>
#
#    This program is free software; you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation; either version 2 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program; if not, write to the Free Software
#    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
#
#

echo $$ > /var/run/fancontrol.pid

function LoadConfig {
	echo "Loading configuration from $1 ..."
	# grep configuration from file
	INTERVAL=`egrep '^INTERVAL=.*$' $1 | sed -e 's/INTERVAL=//g'`
	FCTEMPS=`egrep '^FCTEMPS=.*$' $1 | sed -e 's/FCTEMPS=//g'`
	MINTEMP=`egrep '^MINTEMP=.*$' $1 | sed -e 's/MINTEMP=//g'`
	MAXTEMP=`egrep '^MAXTEMP=.*$' $1 | sed -e 's/MAXTEMP=//g'`
	MINSTART=`egrep '^MINSTART=.*$' $1 | sed -e 's/MINSTART=//g'`
	MINSTOP=`egrep '^MINSTOP=.*$' $1 | sed -e 's/MINSTOP=//g'`

	if [ "$INTERVAL" = "" ]
	then
		echo "Some settings missing..."
		exit 1
	fi
	# here the other settings should be verified
	

	# write settings to arrays for easier use and print them
        echo
	echo "Common settings:"
	echo "  INTERVAL=$INTERVAL"
						
	let fcvcount=0
	for fcv in $FCTEMPS
	do
		AFCPWM[$fcvcount]=`echo $fcv |cut -d'=' -f1`
		AFCTEMP[$fcvcount]=`echo $fcv |cut -d'=' -f2`
		AFCMINTEMP[$fcvcount]=`echo $MINTEMP |sed -s 's/ /\n/g' |egrep "${AFCPWM[$fcvcount]}" |cut -d'=' -f2`
		AFCMAXTEMP[$fcvcount]=`echo $MAXTEMP |sed -s 's/ /\n/g' |egrep "${AFCPWM[$fcvcount]}" |cut -d'=' -f2`
		AFCMINSTART[$fcvcount]=`echo $MINSTART |sed -s 's/ /\n/g' |egrep "${AFCPWM[$fcvcount]}" |cut -d'=' -f2`
		AFCMINSTOP[$fcvcount]=`echo $MINSTOP |sed -s 's/ /\n/g' |egrep "${AFCPWM[$fcvcount]}" |cut -d'=' -f2`
		echo
		echo "Settings for ${AFCPWM[$fcvcount]}:"
		echo "  Depends on ${AFCTEMP[$fcvcount]}"
		echo "  MINTEMP=${AFCMINTEMP[$fcvcount]}"
		echo "  MAXTEMP=${AFCMAXTEMP[$fcvcount]}"
		echo "  MINSTART=${AFCMINSTART[$fcvcount]}"
		echo "  MINSTOP=${AFCMINSTOP[$fcvcount]}"
		let fcvcount=fcvcount+1
	done
	echo
}

if [ -f "$1" ]
then 
	LoadConfig $1
else
	LoadConfig /etc/fancontrol
fi

cd /proc/sys/dev/sensors/

if (( $? != 0 )) ; then 
  echo "Directory /proc/sys/dev/sensors/ does not exist, did you load the necessary kernel modules?"
  exit 1
fi

# function doing all the math
function calc () {
	awk "BEGIN { print $@ }"
}

# main function
function UpdateFanSpeeds {
	let fcvcount=0
	while (( $fcvcount < ${#AFCPWM[@]} )) # go through all pwm outputs
	do
		#hopefully shorter vars will improve readability:
		pwmo=${AFCPWM[$fcvcount]}
		tsens=${AFCTEMP[$fcvcount]}
		mint=${AFCMINTEMP[$fcvcount]}
		maxt=${AFCMAXTEMP[$fcvcount]}
		minsa=${AFCMINSTART[$fcvcount]}
		minso=${AFCMINSTOP[$fcvcount]}
		
		tval=`cat ${tsens} |cut -d' ' -f3 |cut -d'.' -f1`
		pwmpval=`cat ${pwmo}`
		
		# debug info
		#echo "pwmo=$pwmo"
		#echo "tsens=$tsens"
		#echo "mint=$mint"
		#echo "maxt=$maxt"
		#echo "minsa=$minsa"
		#echo "minso=$minso"
		#echo "tval=$tval"
		#echo "pwmpval=$pwmpval"
		
		if (( $tval <= $mint ))
		  then pwmval=0 # at specified mintemp shut fan off
		elif (( $tval >= $maxt ))
		  then pwmval=255 # at specified maxtemp switch to 100%
		else 
		  # calculate the new value from temperature and settings
		  pwmval=`calc "((10/(${maxt}-${mint})*(${tval}-${mint}))^2/1000*(${maxt}-${mint})*(255-${minso})+${minso})" |cut -d'.' -f1`
		  if (( $pwmpval == 0 ))
		  then # if fan was stopped start it using a safe value
		  	echo $minsa > $pwmo
			sleep 1
		  fi
		fi
		echo $pwmval > $pwmo # write new value to pwm output
		fcvcount=$fcvcount+1
	done
}

# main loop calling the main function at specified intervals
while true
do
	UpdateFanSpeeds
	sleep $INTERVAL
done

# some old stuff/missing features, will clean this up soon
#if ( test "$regulationtype" = "quad" ) ; then
#  while true ; do
#    temp=`cat ${temp1} | cut -b 12-13`
#    if (( ${temp} < ${mintemp} )) ;
#    	then pwm=0
#    elif (( ${temp} > ${maxtemp} )) ;
#    	then pwm=255
#    else
#	pwm=`calc "((10/(${maxtemp}-${mintemp})*(${temp}-${mintemp}))^2/1000*(${maxtemp}-${mintemp})*(255-${minspeed})+${minspeed})"`
#	#no optimization here for readability (or sloth :))
#    fi ;
#    echo $pwm > ${pwm1} ;
#
#    sleep 10 ;
#  done ;

#elif ( test "$regulationtype" = "exp" ) ; then
  #add support for exponential calculation here

#else
#  pwmconst=$[(255-${minspeed})/(${maxtemp}-${mintemp})]
#  while true ; do
#    let temp=`cat temp1 | cut -b 12-13` ;
#    if (( ${temp} < ${mintemp} )) ;
#        then pwm=0
#    elif (( ${temp} > ${maxtemp} )) ;
#        then pwm=255
#    else
#    	pwm=$[(${temp}-${mintemp})*${pwmconst}+${minspeed}]
#    fi ;
#    echo $pwm > pwm2 ;
#
#    sleep 10 ;
#  done ;
#fi