From 15d9ec616a5b046fb6983947e973f11f430a0499 Mon Sep 17 00:00:00 2001
From: Johannes Arnold <jarnold@b1-systems.de>
Date: Sun, 25 May 2025 22:16:35 +0200
Subject: [PATCH] nixos/tuxedo-drivers: add optional udev parameters

---
 nixos/modules/hardware/tuxedo-drivers.nix | 77 ++++++++++++++++++++++-
 1 file changed, 75 insertions(+), 2 deletions(-)

diff --git a/nixos/modules/hardware/tuxedo-drivers.nix b/nixos/modules/hardware/tuxedo-drivers.nix
index 154eb09fc895..f53e1297f137 100644
--- a/nixos/modules/hardware/tuxedo-drivers.nix
+++ b/nixos/modules/hardware/tuxedo-drivers.nix
@@ -1,7 +1,25 @@
-{ config, lib, ... }:
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
 let
   cfg = config.hardware.tuxedo-drivers;
   tuxedo-drivers = config.boot.kernelPackages.tuxedo-drivers;
+  udevRule =
+    attr: val:
+    let
+      # Workaround to evaluate true to "1" and false to "0".
+      # Otherwise, true evaluates to "1" and false to "".
+      newVal = if lib.isBool val then (if val then "1" else "0") else val;
+    in
+    lib.concatStringsSep ", " [
+      ''SUBSYSTEM=="platform"''
+      ''DRIVER=="tuxedo_keyboard"''
+      ''ATTR{${attr}}="${newVal}"''
+    ];
+  optUdevRule = attr: val: lib.optional (val != null) (udevRule attr val);
 in
 {
   imports = [
@@ -26,11 +44,66 @@ in
 
       For more inforation it is best to check at the source code description: <https://gitlab.com/tuxedocomputers/development/packages/tuxedo-drivers>
     '';
+    settings = {
+      charging-profile = lib.mkOption {
+        type = lib.types.nullOr (
+          lib.types.enum [
+            "high_capacity"
+            "balanced"
+            "stationary"
+          ]
+        );
+        default = null;
+        description = ''
+          The maximum charge level to help reduce battery wear:
+          - `high_capacity` charges to 100% (driver default)
+          - `balanced` charges to 90%
+          - `stationary` charges to 80% (maximum lifespan)
+
+          **Note:** Regardless of the configured charging profile, the operating system will always report the battery as being charged to 100%.
+        '';
+      };
+      charging-priority = lib.mkOption {
+        type = lib.types.nullOr (
+          lib.types.enum [
+            "charge_battery"
+            "performance"
+          ]
+        );
+        default = null;
+        description = ''
+          These options manage the trade-off between battery charging and CPU performance when the USB-C power supply cannot provide sufficient power for both simultaneously:
+          - `charge_battery` prioritizes battery charging (driver default)
+          - `performance` prioritizes maximum CPU performance
+        '';
+      };
+      fn-lock = lib.mkOption {
+        type = lib.types.nullOr lib.types.bool;
+        default = null;
+        description = ''
+          Enables or disables the laptop keyboard's Function (Fn) lock at boot.
+
+          When set to `true`, the Fn lock is enabled, allowing the function keys (F1–F12) to control brightness, volume etc.
+        '';
+      };
+    };
   };
 
   config = lib.mkIf cfg.enable {
     boot.kernelModules = [ "tuxedo_keyboard" ];
     boot.extraModulePackages = [ tuxedo-drivers ];
-    services.udev.packages = [ tuxedo-drivers ];
+    services.udev.packages = [
+      tuxedo-drivers
+      lib.mkIf
+      (lib.any (v: v != null) cfg.settings)
+      (pkgs.writeTextDir "etc/udev/rules.d/90-tuxedo.rules" (
+        lib.concatLines (
+          [ "# Custom rules for TUXEDO laptops" ]
+          ++ (optUdevRule "charging_profile/charging_profile" cfg.settings.charging-profile)
+          ++ (optUdevRule "charging_priority/charging_prio" cfg.settings.charging-priority)
+          ++ (optUdevRule "fn_lock" cfg.settings.fn-lock)
+        )
+      ))
+    ];
   };
 }