Ie: download the script and systemd service, edit the script to your liking (or try default) and activate the service.
As default It configures to user_space and checks temps every 10s.
https://raw.githubusercontent.com/c0m4r/radxa_rock5c_lite/refs/heads/main/usr/local/bin/rock5c_fan_pwm
##########################################################
# Radxa Rock 5C fan PWM control script
# Author: https:///github.com/c0m4r
# License: Public Domain
##########################################################
# PWM control path
PWM_PATH="/sys/devices/platform/pwm-fan/hwmon"
# Configuration
INTERVAL=10 # Temperature check interval (seconds)
FAN_OFF=1 # 1 = turn off fan below MIN_TEMP after cooldown, 0 = keep at min RPM
COOLDOWN=300 # time to wait before turning off the fan when FAN_OFF=1
# Critical temp protection
POWEROFF_ON_CRIT=1 # 1 = shutdown when the temperature reaches a critical value, 0 = disable
CRITICAL_TEMP=70 # Critical temperature (shutdown)
# PWM Values (proper)
SAFE_PWM_MIN=105 # Safe minimum PWM to keep fan spinning
PWM_LOW=125 # 45–50°C (~50% speed)
PWM_MID=165 # 50–55°C (~65% speed)
PWM_HIGH=200 # 55–60°C (~80% speed)
PWM_MAX=255 # >60°C (100% speed)
# PWM Values (temporary - use these instead of proper if the fan spins at max all the time)
#SAFE_PWM_MIN=50 # Safe minimum PWM to keep fan spinning
#PWM_LOW=60 # 45–50°C (~50% speed)
#PWM_MID=70 # 50–55°C (~65% speed)
#PWM_HIGH=80 # 55–60°C (~80% speed)
#PWM_MAX=255 # >60°C (100% speed)
# Constants (requires also changes in code)
MIN_TEMP=47 # Minimum temperature (PWM_MIN)
MAX_TEMP=60 # Maximum temperature (PWM_MAX)
# Set thermal policy
thermal_zones=$(ls -1 /sys/class/thermal | grep thermal_zone)
if [[ "$thermal_zones" ]]; then
for i in /sys/class/thermal/thermal_zone*/policy ; do
echo "user_space" > "$i"
done
else
echo "No sensors found, check kernel support, setting fan to high for now!"
echo $PWM_HIGH > ${PWM_PATH}/hwmon*/pwm1
exit 1
fi
# Set PWM_MIN based on FAN_OFF mode
if [ "$FAN_OFF" -eq 1 ]; then
PWM_MIN=0 # Allow fan to turn off after cooldown
else
PWM_MIN=$SAFE_PWM_MIN # Keep fan at minimal safe RPM all the time
fi
# Validate PWM path
if [ ! -d "$PWM_PATH" ]; then
echo "Error: PWM control file not found: $PWM_PATH"
exit 1
fi
# Initialize variables
current_pwm=$(cat ${PWM_PATH}/hwmon*/pwm1) # Start at current PWM
last_high_temp_time=0 # Track last high temp for cooldown
echo "Initializing fan at PWM $current_pwm"
echo "$current_pwm" > ${PWM_PATH}/hwmon*/pwm1
# Main loop
while true; do
for i in /sys/class/thermal/thermal_zone*/policy ; do
echo "user_space" > "$i"
done
<snip>
