ethercat: add kernel module

pkgs/by-name/et/ethercat/kernel-module.nix

@@ -0,0 +1,70 @@
+ethercat:
+{
+  lib,
+  stdenv,
+  kernelModuleMakeFlags,
+  kernel,
+}:
+let
+  # Aside from a generic drivers there are special drivers for specific NICs
+  # (for example r8139, r8169, e100, e1000, e1000e) which are only available
+  # for these kernel versions
+  extraSupportedKernel = lib.elem (lib.versions.majorMinor kernel.version) [
+    "5.10"
+    "5.14"
+    "5.15"
+    "6.1"
+    "6.4"
+    "6.12"
+  ];
+in
+stdenv.mkDerivation {
+  pname = "ethercat";
+  version = "${kernel.version}-${ethercat.version}";
+
+  __structuredAttrs = true;
+
+  enableParallelBuilding = true;
+
+  inherit (ethercat) src;
+
+  nativeBuildInputs = kernel.moduleBuildDependencies ++ ethercat.nativeBuildInputs;
+
+  configureFlags = [
+    "--with-linux-dir=${kernel.dev}/lib/modules/${kernel.modDirVersion}/build"
+    "--enable-userlib=no"
+    "--enable-tool=no"
+    "--enable-kernel=yes"
+    "--enable-ccat=yes"
+  ]
+  ++ lib.optionals extraSupportedKernel [
+    "--enable-e100=yes"
+    "--enable-e1000=yes"
+    "--enable-e1000e=yes"
+    "--enable-r8169=yes"
+    "--enable-igb=yes"
+  ]
+  ++ lib.optionals (extraSupportedKernel && lib.versionAtLeast kernel.version "5.14") [
+    "--enable-igc=yes"
+  ];
+
+  makeFlags = kernelModuleMakeFlags ++ [
+    "INSTALL_MOD_PATH=${placeholder "out"}"
+  ];
+
+  buildFlags = [ "modules" ];
+
+  installTargets = [ "modules_install" ];
+
+  meta = {
+    description = ethercat.meta.description + " - kernel modules";
+
+    inherit (ethercat.meta)
+      homepage
+      changelog
+      license
+      maintainers
+      platforms
+      ;
+  };
+}

pkgs/by-name/et/ethercat/package.nix

@@ -29,7 +29,10 @@ stdenv.mkDerivation (finalAttrs: {
     "--enable-kernel=no"
   ];
 
-  passthru.updateScript = gitUpdater { };
+  passthru = {
+    kernelModule = import ./kernel-module.nix finalAttrs.finalPackage;
+    updateScript = gitUpdater { };
+  };
 
   meta = {
     description = "IgH EtherCAT Master for Linux";

pkgs/top-level/linux-kernels.nix

@@ -332,6 +332,8 @@ in
           inherit kernel;
         };
 
+        ethercat = callPackage pkgs.ethercat.kernelModule { };
+
         evdi = callPackage ../os-specific/linux/evdi { };
 
         fanout = callPackage ../os-specific/linux/fanout { };