nixos-config/modules/fancontrol.nix

# SPDX-FileCopyrightText: 2023 Simon Bruder <simon@sbruder.de>
#
# SPDX-License-Identifier: AGPL-3.0-or-later

{ config, lib, pkgs, ... }:
let
  cfg = config.sbruder.fancontrol;
in
{
  options.sbruder.fancontrol = {
    enable = lib.mkEnableOption "afancontrol based fancontrol";
    package = lib.mkOption {
      type = lib.types.package;
      default = pkgs.afancontrol;
      description = "The afancontrol package to use.";
    };
    interval = lib.mkOption {
      type = lib.types.int;
      default = 1;
      description = "Interval in seconds the fan speeds should be calculated and set.";
    };
    enableDefaultMapping = lib.mkEnableOption "the default mapping, mapping all sensors to all fans";
    fans = lib.mkOption {
      type = lib.types.attrsOf (lib.types.submodule {
        options = {
          pwmFile = lib.mkOption {
            type = lib.types.path;
            description = "File to write the PWM duty cycle to.";
          };
          pwmLineStart = lib.mkOption {
            type = lib.types.int;
            default = 0;
            description = "PWM value at which the linear correlation of PWM/RPM starts.";
          };
          pwmLineEnd = lib.mkOption {
            type = lib.types.int;
            default = 255;
            description = "PWM value at which the linear correlation of PWM/RPM ends.";
          };
          rpmFile = lib.mkOption {
            type = lib.types.path;
            description = "File to read the fan RPM from.";
          };
          neverStop = lib.mkOption {
            type = lib.types.bool;
            default = false;
            description = "Whether to stop the fan on speed 0% (otherwise runs with pwmLineStart).";
          };
        };
      });
      default = { };
    };
    sensors = lib.mkOption {
      type = lib.types.attrsOf (lib.types.submodule {
        options = {
          file = lib.mkOption {
            type = lib.types.path;
            description = "File to read the temperature (in m°C) from.";
          };
          min = lib.mkOption {
            type = lib.types.int;
            description = "Temperature at which the fan speed is lowest.";
          };
          max = lib.mkOption {
            type = lib.types.int;
            description = "Temperature at which the fan speed is highest.";
          };
        };
      });
      default = { };
    };
    mappings = lib.mkOption {
      type = lib.types.attrsOf (lib.types.submodule {
        options = {
          fans = lib.mkOption {
            type = lib.types.listOf (lib.types.str);
            description = "Fans to map.";
          };
          sensors = lib.mkOption {
            type = lib.types.listOf (lib.types.str);
            description = "Sensors to map.";
          };
        };
      });
      default =
        if cfg.enableDefaultMapping then {
          all = {
            fans = lib.attrNames cfg.fans;
            sensors = lib.attrNames cfg.sensors;
          };
        } else { };
    };
  };
  config = lib.mkIf cfg.enable {
    # makes some assumptions
    #systemd.packages = [ cfg.package ];

    systemd.services.afancontrol = {
      wantedBy = [ "multi-user.target" ];
      serviceConfig = {
        LimitNOFILE = 8192;
        ExecStartPre = "${cfg.package}/bin/afancontrol daemon --test";
        ExecStart = "${cfg.package}/bin/afancontrol daemon --pidfile /run/afancontrol.pid";
        PIDFile = "/run/afancontrol.pid";
        Restart = "always";
      };
    };

    environment.etc."afancontrol/afancontrol.conf".text = lib.generators.toINI
      {
        mkKeyValue = lib.generators.mkKeyValueDefault
          {
            mkValueString = v:
              if lib.isList v then lib.concatMapStringsSep ", " toString v
              else lib.generators.mkValueStringDefault { } v;
          }
          ":";
      }
      ({
        daemon = {
          interval = 1;
        };

        actions = {
          report_cmd = "true";
        };
      } // (lib.mapAttrs'
        (name: config: lib.nameValuePair "fan: ${name}" {
          type = "linux";
          pwm = config.pwmFile;
          fan_input = config.rpmFile;
          pwm_line_start = config.pwmLineStart;
          pwm_line_end = config.pwmLineEnd;
          never_stop = config.neverStop;
        })
        cfg.fans
      ) // (lib.mapAttrs'
        (name: config: lib.nameValuePair "temp: ${name}" {
          type = "file";
          path = config.file;
          inherit (config) min max;
        })
        cfg.sensors
      ) // (lib.mapAttrs'
        (name: config: lib.nameValuePair "mapping: ${name}" {
          inherit (config) fans;
          temps = config.sensors;
        })
        cfg.mappings
      ));
  };
}