services: port amdgpu services from private config

modules/services/hardware/amdgpu-fan.nix

@@ -0,0 +1,71 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+
+  acfg = config.services.amdgpu;
+  cfg = config.services.amdgpu.fan;
+
+in
+
+{
+  options.services.amdgpu.fan = {
+    enable = mkEnableOption "amdgpu-fan";
+
+    speedMatrix = mkOption {
+      type = with types; listOf (listOf int);
+      # Translated from upstream default config. Since it tries to write the
+      # config if it's not found, we want some kind of default.
+      default = [
+        [ 0 0 ]
+        [ 30 33 ]
+        [ 45 50 ]
+        [ 60 66 ]
+        [ 65 69 ]
+        [ 70 75 ]
+        [ 75 89 ]
+        [ 80 100 ]
+      ];
+      example = literalExample ''
+        [
+          [ 0 0 ]
+          [ 40 30 ]
+          [ 60 50 ]
+          [ 80 100 ]
+        ]
+      '';
+      description = ''
+        A list of temperature-fan speed pairs. The temperature is specified in
+        degrees celcius, and speed is specified in %.
+      '';
+    };
+  };
+
+  config = mkIf cfg.enable {
+    assertions = singleton {
+      assertion = all (speeds: length speeds == 2) cfg.speedMatrix;
+      message = "services.amdgpu-fan.speedMatrix must be a list of paired lists";
+    };
+
+    environment.etc."amdgpu-fan.yml".text = builtins.toJSON {
+      speed_matrix = cfg.speedMatrix;
+      cards = acfg.cards;
+    };
+
+    powerManagement.resumeCommands = "${pkgs.systemd}/bin/systemctl try-restart amdgpu-fan";
+
+    # Translated from the upstream service file.
+    systemd.services = {
+      amdgpu-fan = {
+        description = "amdgpu fan controller";
+        wantedBy = [ "default.target" ];
+        after = [ "enable-manual-amdgpu-fan.service" ];
+        serviceConfig = {
+          ExecStart = "${pkgs.amdgpu-fan}/bin/amdgpu-fan";
+          Restart = "always";
+        };
+      };
+    };
+  };
+}