The current Armbian image (as of 2024-11-02) for the CM3588 doesn't enable the fan control node in the Device Tree, so instead, we can set the GPIO chip connected to the fan connector to PWM mode and use that to control fan speed.
sudo cp fanctl.service /etc/systemd/system
sudo cp fanctl /usr/local/sbin
sudo systemctl daemon-reload
sudo systemctl enable --now fanctl
If after starting the service, the fan emits coild whine and doesn't spin up, you need to increase the minium speed. Either change it in the script directly and restart the service, or stop the service and echo the values (multipiled with 1000, value must be betwen 1 and 100000) to sysfs:
# set speed to 50 of 100:
echo 50000 | sudo tee /sys/class/pwm/pwmchip0/pwm0/duty_cycle
My Noctua fan needed only 30, while the fan that was delivered with the metal case needed between 42 and 46 to reliably spin up.