https://github.com/mgdm/argonone-utils

A fan control daemon for the Argon ONE case for the Raspberry Pi 4.
https://github.com/mgdm/argonone-utils

Last synced: 2 months ago
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A fan control daemon for the Argon ONE case for the Raspberry Pi 4.

• Host: GitHub
• URL: https://github.com/mgdm/argonone-utils
• Owner: mgdm
• License: bsd-2-clause
• Created: 2021-09-19T19:55:22.000Z (over 3 years ago)
• Default Branch: main
• Last Pushed: 2022-01-10T14:54:32.000Z (almost 3 years ago)
• Last Synced: 2024-06-21T18:03:13.839Z (6 months ago)
• Language: Nix
• Size: 10.7 KB
• Stars: 8
• Watchers: 2
• Forks: 3
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# Argon ONE utils

This repo provides two things:

* A port of the logic of the [Argon ONE fan control daemon script](https://download.argon40.com/argon1.sh) to Go instead of Python.

* Some systemd and device tree configuration to make the power button shut down the machine cleanly.

**This probably won't work for you**. I use this on my [Raspberry Pi 4B running NixOS](https://mgdm.net/weblog/nixos-on-raspberry-pi-4/). Everything is hard coded to work on that machine with no accounting for other OSes or configurations.

**There's no warranty of any kind for this.**

## I'm using NixOS! How do I set up the fan control daemon?

The Argon ONE's fan is controlled using I2C. On Raspbian, enabling I2C is a simple matter of using `raspi-config`, which will add a line similar to `dtparam=i2c_arm=on` to `/boot/config.txt`, and rebooting. This doesn't work for me on NixOS even using the Raspberry Pi vendor kernel, so I had to work on a device tree overlay to enable it instead. For some reason I think the I2C bus names under NixOS are swapped, so this code works with `i2c-1` whereas on Raspbian I believe it would be `i2c-0`, though I have not tested this.

The overlay looks like [nix/hardware/i2c.nix](nix/hardware/i2c.nix). Copy that somewhere under `/etc/nixos` and include that in your `configuration.nix` as follows:

```nix

{   

    imports =

    [

        ./hardware-configuration.nix

        ./hardware/i2c.nix

    ];

    # Other settings go here...

    hardware.raspberry-pi."4".i2c.enable = true;

}

```

(This option name uses the convention of the [nixos-hardware overlay](https://github.com/NixOS/nixos-hardware/), to which I will eventually PR this).

Then to configure the service:

```nix

{

#    Import the overlay to provide the argonone-utils package

    nixpkgs.overlays = [ (import ./overlays) ];

    systemd.services.argonone-fancontrold = {

        enable = true;

        wantedBy = [ "default.target" ];

        serviceConfig = {

            DynamicUser = true;

            Group = "i2c";

            ExecStart = "${pkgs.argonone-utils}/bin/argonone-fancontrold";

        };

    };

}

```

In `hardware-configuration.nix`, I made the following additions:

```nix

{

    boot.initrd.kernelModules = [  "i2c-dev" "i2c-bcm2835"  ];

    boot.kernelModules = [ "i2c-dev" "i2c-bcm2835" ];

    hardware.i2c.enable = true; # This adds the i2c group

}

```

Hopefully that should be it!

## I'm using NixOS! How do I make the power button work?

Most of the functionality for making the power button turn the machine off already exists in the kernel and systemd. There's no need for a script to monitor the GPIOs unless you want to do something different like a quick press for reboot or a long press for shut down. The supplied Argon ONE script monitors the GPIO at 100Hz in order to do this. 

I thought about rewriting this like I did with the fan control, but using interrupts, but then I got told by [@adventureloop](https://github.com/adventureloop/) about the `gpio-keys` kernel module. This needs some device tree overlays to set up on NixOS (again, it's probably simpler on Raspbian), but once the overlay is applied systemd will respond to a double tap on the power button by shutting down. This is only the first step--it doesn't turn off the power to the Pi. However, with a quick systemd one-shot unit, we can poke the right I2C command at the board to make it cut the power just after everything else is shut down.

To use it:

* include [power-button.nix](nix/hardware/power-button.nix) in your configuration

* add `gpio-keys` to boot.kernelModules (I will add this to power-button.nix eventually)

* enable it using `hardware.argon-one.power-button.enable = true;`

After a rebuild, a double tap the power button should cleanly shut down and turn the machine off.