Simple script to control pwm fans using a defined curve; requires a companion script to actually send the correct command to the fan controller.

fancontrol.sh

#!/bin/bash

INTERVAL="10s"
INPUT_DRIVER="coretemp"
#TEMP_PATH="/sys/class/hwmon/hwmon3/temp1_input"
FAN_CMD="/usr/bin/fan.sh"

# Find correct input temperature path
for hwmon in `ls /sys/class/hwmon/`; do
        driver=$(</sys/class/hwmon/$hwmon/name)
        if [ "$driver" == "$INPUT_DRIVER" ]; then
                break
        fi
done
TEMP_PATH="/sys/class/hwmon/$hwmon/temp1_input"


CURVE=lin_curve

lin_curve() {
        m=11
        q=-640
        echo "obase=16; r = $m * $1 + $q; if ( r<48 ) 0 else r" | bc
}

while true; do
        temp="$(( $(cat $TEMP_PATH) / 1000 ))"
        ${FAN_CMD} "$($CURVE $temp)"
        sleep "${INTERVAL}"
done