diff --git a/scripts/amd-fan-control b/scripts/amd-fan-control
index 5b0d7a9..e014acf 100755
--- a/scripts/amd-fan-control
+++ b/scripts/amd-fan-control
@@ -2,85 +2,144 @@
 
 set -e
 
-DEVICE="$1" # eg: /sys/class/drm/card1/device
-HWMON=$(echo "$DEVICE"/hwmon/hwmon*)
-
-exit() {
-    echo "Setting controll to auto" >&2
-    echo 2 > "$HWMON/pwm1_enable"
-}
-
-trap exit EXIT INT
-
 bail() {
     echo "Error: $@" >&2
     echo "Exiting..." >&2
     exit 1
 }
 
-if ! [ -d "$HWMON" ]; then
-    bail "Invalid HWMON"
-fi
+map_range() {
+    VALUE="$1"
+    MIN_INPUT="$2"
+    MAX_INPUT="$3"
+    INPUT_RANGE=$(( $MAX_INPUT - $MIN_INPUT ))
+    MIN_OUTPUT="$4"
+    MAX_OUTPUT="$5"
+    OUTPUT_RANGE=$(( $MAX_OUTPUT - $MIN_OUTPUT ))
 
-TEMP_INPUT="$HWMON/temp2_input"
+    echo $(( ($VALUE - $MIN_INPUT) * $OUTPUT_RANGE / $INPUT_RANGE  + $MIN_OUTPUT ))
+}
 
-if ! [ -f $TEMP_INPUT ]; then
-    bail "Invalid TEMP_INPUT"
-fi
+clamp() {
+    VALUE="$1"
 
-TEMP_MIN="$2"
-TEMP_MAX="$3"
+    MIN="$2"
+    MAX="$3"
 
-if [ -z "$TEMP_MIN" ];then
-  bail "No minimum temperature provided"
-fi
-
-if [ -z "$TEMP_MAX" ];then
-  bail "No maximum temperature provided"
-fi
-
-PWM_MIN_PCT="$4"
-PWM_MAX_PCT="$5"
-
-if [ -z "$PWM_MIN_PCT" ];then
-  bail "No minimum fan speed % not provided"
-fi
-
-if [ -z "$PWM_MAX_PCT" ];then
-  bail "No maximum fan speed % not provided"
-fi
-
-PWM_MIN="$(( $PWM_MIN_PCT * 255 / 100))"
-PWM_MAX="$(( $PWM_MAX_PCT * 255 / 100))"
-
-echo "Running..." >&2
-
-echo "TEMP_MIN=$TEMP_MIN°C"
-echo "TEMP_MAX=$TEMP_MAX°C"
-echo "FAN_MIN=$PWM_MIN_PCT%"
-echo "FAN_MAX=$PWM_MAX_PCT%"
-
-echo 1 > "$HWMON/pwm1_enable"
-
-PREV=0
-
-while true; do
-    TEMPERATURE_RAW=$(cat "$TEMP_INPUT")
-    TEMPERATURE="$(( $TEMPERATURE_RAW / 1000 ))"
-    # Remap from a number between 60_000..90_000 to 0..255
-    PWM=$(( ($TEMPERATURE - $TEMP_MIN) * $PWM_MAX / ($TEMP_MAX - $TEMP_MIN) ))
-
-    if [ "$PWM" -gt $PWM_MAX ]; then
-        PWM=$PWM_MAX
-    elif [ "$PWM" -lt $PWM_MIN ]; then
-        PWM=$PWM_MIN
+    VALUE=$VALUE
+    if [ "$VALUE" -gt $MAX ]; then
+        VALUE=$MAX
+    elif [ "$VALUE" -lt $MIN ]; then
+        VALUE=$MIN
     fi
 
-    AVG="$(( ($PWM * 20 + $PREV * 80) / 100 ))"
+    echo $VALUE
+}
 
-    echo "$AVG"
+cleanup() {
+    echo "Setting controll to auto" >&2
+    if test -f "$HWMON/pwm1_enable"; then
+        echo 2 > "$HWMON/pwm1_enable"
+    fi
+}
+trap cleanup EXIT INT
 
-    echo "$AVG" > "$HWMON/pwm1"
-    PREV="$AVG"
+usage() {
+    echo "Usage: $0 <device> <min-temp> <max-temp> <min-fan> <max-fan>" >&2
+    echo "Example: $0 /sys/class/drm/card1/device 60 100 10 80" >&2
+    exit 1
+}
+
+parse_cli() {
+    if test -n "$AMDGPU_FAN_CRONTROL_DEBUG"; then
+        echo parse_cli "$@" >&2
+    fi
+
+    DEVICE="$1" # eg: /sys/class/drm/card1/device
+    HWMON=$(echo "$DEVICE"/hwmon/hwmon*)
+    TEMP_INPUT="$HWMON/temp2_input"
+
+    TEMP_MIN="$2"
+    TEMP_MAX="$3"
+
+    PWM_MIN_PCT="$4"
+    PWM_MAX_PCT="$5"
+}
+
+validate_variables() {
+    if ! [ -d "$HWMON" ]; then
+        bail "Invalid drm-device: '$HWMON' is not a directory"
+    fi
+
+    if ! [ -f "$TEMP_INPUT" ]; then
+        bail "Error: Could not find hotspot temperature at '$TEMP_INPUT'"
+    fi
+
+    if [ -z "$TEMP_MIN" -o -z "$TEMP_MAX" -o -z "$PWM_MIN_PCT" -o -z "$PWM_MAX_PCT" ];then
+        usage
+    fi
+}
+
+setup() {
+    PWM_MIN=$(map_range $PWM_MIN_PCT 0 100 0 255)
+    PWM_MAX=$(map_range $PWM_MAX_PCT 0 100 0 255)
+
+    echo "Running..." >&2
+
+    if test -n "$AMDGPU_FAN_CRONTROL_DEBUG"; then
+        echo "TEMP_MIN=$TEMP_MIN°C" >&2
+        echo "TEMP_MAX=$TEMP_MAX°C" >&2
+        echo "FAN_MIN=$PWM_MIN_PCT% (PWM=$PWM_MIN)" >&2
+        echo "FAN_MAX=$PWM_MAX_PCT% (PWM=$PWM_MAX)" >&2
+    fi
+
+    # Set fan control mode to manual, this will be reverted in the cleanup trap
+    echo 1 > "$HWMON/pwm1_enable"
+
+    PREV_PWM=0
+}
+
+main_loop() {
+    TEMPERATURE_RAW=$(cat "$TEMP_INPUT")
+    TEMPERATURE="$(( $TEMPERATURE_RAW / 1000 ))" # 60_000 = 60°C
+
+    # Calculate the fan speed we would want to reach given infinite time
+    TARGET_PWM=$(map_range $TEMPERATURE $TEMP_MIN $TEMP_MAX $PWM_MIN $PWM_MAX)
+
+    # Calculate an appropriate amount to "walk" in the direction of target fan speed
+    DIFFERENCE=$(( $TARGET_PWM - $PREV_PWM ))
+    ADJUSTMENT=$(( $DIFFERENCE * 20 / 100 ))
+
+    NEXT_PWM=$(( $PREV_PWM + $ADJUSTMENT ))
+
+    NEXT_PWM=$(clamp $NEXT_PWM $PWM_MIN $PWM_MAX)
+    NEXT_PWM_PCT=$(map_range $NEXT_PWM 0 255 0 100 )
+
+    if test -n "$AMDGPU_FAN_CRONTROL_DEBUG"; then
+        for var in \
+            "Temperature=$TEMPERATURE°C" \
+            "Fan speed=$NEXT_PWM_PCT%" \
+        ; do
+            echo -en "$var\t"
+        done
+        echo
+    fi
+
+    # Apply the new fan speed
+    echo "$NEXT_PWM" > "$HWMON/pwm1"
+
+    # Wait for next iteratino
+    PREV_PWM="$NEXT_PWM"
     sleep .1s
-done
+}
+
+main() {
+    parse_cli "$@"
+    validate_variables
+    setup
+    while true; do
+        main_loop
+    done
+}
+
+main "$@"