nix: basic packaging

Signed-off-by: NotAShelf <raf@notashelf.dev>
Change-Id: I6a6a6964c848d4871ead297560a06c2e1dd2f14d

nix/kmod.nix

@@ -0,0 +1,76 @@
+{
+  lib,
+  stdenv,
+  linuxPackages_latest,
+  kernel ? linuxPackages_latest.kernel,
+  ...
+}: let
+  pname = "deepcool";
+  version = "0.1.0";
+in
+  stdenv.mkDerivation {
+    inherit pname version;
+
+    src = let
+      fs = lib.fileset;
+      sp = ../.;
+    in
+      fs.toSource {
+        root = sp;
+        fileset = fs.unions [
+          (sp + /deepcool.c)
+          (sp + /Makefile)
+        ];
+      };
+
+    enableParallelBuilding = true;
+    nativeBuildInputs = kernel.moduleBuildDependencies;
+    hardeningDisable = ["pic" "format"];
+
+    env = {
+      KVERSION = kernel.modDirVersion;
+      INSTALL_MOD_PATH = builtins.placeholder "out";
+    };
+
+    buildPhase = ''
+      runHook preBuild
+      echo "Kernel version: $KVERSION"
+      make -C ${kernel.dev}/lib/modules/${kernel.modDirVersion}/build \
+        M=$(pwd) \
+        modules
+      runHook postBuild
+    '';
+
+    installPhase = ''
+      runHook preInstall
+      echo "Module Installation Path: $INSTALL_MOD_PATH"
+      make -C ${kernel.dev}/lib/modules/${kernel.modDirVersion}/build \
+        M=$(pwd) \
+        modules_install
+      runHook postInstall
+    '';
+
+    postInstall = ''
+      if [ -d $out/lib/modules/${kernel.modDirVersion}/extra ]; then
+        mkdir -p $out/lib/modules/${kernel.modDirVersion}/kernel/drivers/hid
+        find $out/lib/modules/${kernel.modDirVersion}/extra -name "*.ko*" \
+          -exec mv {} $out/lib/modules/${kernel.modDirVersion}/kernel/drivers/hid/ \;
+        rmdir $out/lib/modules/${kernel.modDirVersion}/extra 2>/dev/null || true
+      fi
+    '';
+
+    passthru = {
+      inherit kernel;
+      kernelVersion = kernel.modDirVersion;
+      moduleName = "deepcool_digital";
+      modulePath = "kernel/drivers/hid/deepcool_digital.ko";
+    };
+
+    meta = {
+      description = "Linux kernel module for Deepcool Digital USB HID devices";
+      license = lib.licenses.gpl2Plus;
+      maintainers = [];
+      platforms = lib.platforms.linux;
+      broken = lib.versionOlder kernel.version "5.10";
+    };
+  }