Fan speed control with pwm0

This is a tiny service to drive the Fan speed according to CPU Temp. Higher Cpu temperature makes the Fan speed faster.

Currently there are 6 Cpu temp. and it can be adjusted to your Fan model. This has been tested with snowfan model in NanoPi R2S and mainline kernel.

The mainline kernel must expose the pwm0.

Install instructions

Run in the shell:

make
sudo make install

After the installation you can check if the service is running, by hearing the Fan spinning lower or checking the service:

• Status of the service

    sudo systemctl status fan-monitor
  
    ● fan-monitor.service - FAN speed control
         Loaded: loaded (/lib/systemd/system/fan-monitor.service; enabled; vendor preset: enabled)
         Active: active (exited) since Tue 2020-10-06 18:14:34 UTC; 26min ago
        Process: 536 ExecStart=/usr/local/bin/fan-monitor64 (code=exited, status=0/SUCCESS)
       Main PID: 536 (code=exited, status=0/SUCCESS)
          Tasks: 1 (limit: 1145)
         Memory: 184.0K
         CGroup: /system.slice/fan-monitor.service
                 └─538 /usr/local/bin/fan-monitor64
    
    Oct 06 18:14:34 nanopi-r2s systemd[1]: Starting FAN speed control...
    Oct 06 18:14:34 nanopi-r2s systemd[1]: Finished FAN speed control.
  

• Stop the service

    sudo systemctl stop fan-monitor
  

• Start the service

    sudo systemctl start fan-monitor
  

Enhancements

• Polarity support

You can build the service to set pwm0 with 'normal' polarity instead of 'inversed'.

	make clean
	EXTRAFLAGS='-DPOLARITY=1' make

• Update the running servide with:

    sudo systemctl stop fan-monitor
    sudo make update
    sudo systemctl start fan-monitor