hitagi: Add manual fan control for case fans

The firmware does not allow using multiple sensors (CPU and GPU) for one
fan output.

machines/hitagi/hardware-configuration.nix

@@ -6,8 +6,13 @@
   ];
 
   boot = {
-    kernelModules = [ "kvm-amd" ];
-    extraModulePackages = [ ];
+    # fan control configuration from https://gist.github.com/bakman2/e801f342aaa7cade62d7bd54fd3eabd8
+    kernelModules = [ "kvm-amd" "it87" ];
+    kernelParams = [ "acpi_enforce_resources=lax" ]; # allow it87 to load
+    extraModulePackages = with config.boot.kernelPackages; [ it87 ];
+    extraModprobeConfig = ''
+      options it87 force_id=0x8688
+    '';
     loader = {
       grub.enable = false;
       systemd-boot.enable = true;
@@ -98,4 +103,38 @@
       Type = "oneshot";
     };
   };
+
+  sbruder.fancontrol = {
+    enable = true;
+    enableDefaultMapping = true;
+    fans = {
+      front = {
+        pwmFile = "/sys/class/hwmon/hwmon1/pwm4";
+        rpmFile = "/sys/class/hwmon/hwmon1/fan4_input";
+        pwmLineStart = 50;
+        neverStop = true;
+      };
+      back = {
+        pwmFile = "/sys/class/hwmon/hwmon1/pwm2";
+        rpmFile = "/sys/class/hwmon/hwmon1/fan2_input";
+      };
+    };
+    sensors = {
+      cpu = {
+        file = "/sys/class/hwmon/hwmon2/temp3_input";
+        min = 50;
+        max = 80;
+      };
+      gpu = {
+        file = "/sys/class/hwmon/hwmon4/temp1_input";
+        min = 50;
+        max = 70;
+      };
+      nvme = {
+        file = "/sys/class/hwmon/hwmon0/temp1_input";
+        min = 40;
+        max = 70;
+      };
+    };
+  };
 }