Add Nix support

Makefile

@@ -26,7 +26,7 @@ modules:
 install: modules_modules
 
 modules_modules:
-	$(foreach mod,$(DRIVER),/usr/bin/install -m 644 -D $(mod).ko $($(mod)_DEST_DIR)/$(mod).ko;)
+	$(foreach mod,$(DRIVER),install -m 644 -D $(mod).ko $($(mod)_DEST_DIR)/$(mod).ko;)
 	depmod -a -F $(SYSTEM_MAP) $(TARGET)
 
 clean:

flake.nix

@@ -0,0 +1,63 @@
+{
+  description = "Install Asustor kernel modules on NixOS";
+
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
+  };
+
+  outputs = { self, nixpkgs }:
+    let
+      system = "x86_64-linux";
+      pkgs = nixpkgs.legacyPackages.${system};
+      module =
+        ({ stdenv, lib, kernel, kmod, ... }:
+
+          stdenv.mkDerivation rec {
+            name = "asustor-platform-driver-${version}-${kernel.version}";
+            version = "0.1";
+
+            src = ./.;
+
+            hardeningDisable = [ "pic" "format" ];
+            # Install kmod for depmod dependency if we need it
+            #nativeBuildInputs = kernel.moduleBuildDependencies ++ [ kmod ];
+            nativeBuildInputs = kernel.moduleBuildDependencies;
+
+            buildFlags = [
+              "KERNEL_MODULES=${kernel.dev}/lib/modules/${kernel.modDirVersion}"
+            ];
+            installFlags = [
+              "KERNEL_MODULES=${placeholder "out"}/lib/modules/${kernel.modDirVersion}"
+            ];
+
+            # TODO: check if we need depmod.
+            preConfigure = ''
+              sed -i 's|depmod|#depmod|' Makefile
+            '';
+
+            meta = with lib; {
+              description = "A kernel module to support Asustor devices";
+              homepage = "https://github.com/mafredri/asustor-platform-driver";
+              license = licenses.gpl3;
+              maintainers = [ ];
+              platforms = platforms.linux;
+            };
+          });
+    in
+    {
+      packages.${system}.default = pkgs.callPackage ./default.nix { };
+      nixosModules.default = ({ config, lib, ... }:
+        let
+          asustor-platform-driver = config.boot.kernelPackages.callPackage module { };
+        in
+        {
+          options = {
+            hardware.asustor.enable = lib.mkEnableOption "Enable the Asustor kernel module";
+          };
+          config = lib.mkIf config.hardware.asustor.enable {
+            boot.extraModulePackages = [ asustor-platform-driver ];
+          };
+        });
+      formatter.${system} = pkgs.nixpkgs-fmt;
+    };
+}