config.hardware.onlykey configuration option

By default, OnlyKey device (https://crp.to/p/) won't work on Linux (and,
therefore, NixOS). This is unintuitive and requires one to search for a
solution in the documentation.

This change allows one to enable OnlyKey device support directly from
their NixOS configuration.

nixos/modules/hardware/onlykey.nix

@@ -0,0 +1,33 @@
+{ config, lib, ... }:
+
+with lib;
+
+{
+
+  ####### interface
+
+  options = {
+
+    hardware.onlykey = {
+      enable = mkOption {
+        type = types.bool;
+        default = false;
+        description = ''
+          Enable OnlyKey device (https://crp.to/p/) support.
+        '';
+      };
+    };
+
+  };
+
+  ## As per OnlyKey's documentation piece (hhttps://docs.google.com/document/d/1Go_Rs218fKUx-j_JKhddbSVTqY6P0vQO831t2MKCJC8),
+  ## it is important to add udev rule for OnlyKey for it to work on Linux
+
+  ####### implementation
+
+  config = mkIf config.hardware.onlykey.enable {
+    services.udev.extraRules = builtin.readFile ./onlykey.udev;
+  };
+
+
+}

nixos/modules/hardware/onlykey.udev

@@ -0,0 +1,4 @@
+ATTRS{idVendor}=="16c0", ATTRS{idProduct}=="04[789B]?", ENV{ID_MM_DEVICE_IGNORE}="1"
+ATTRS{idVendor}=="16c0", ATTRS{idProduct}=="04[789A]?", ENV{MTP_NO_PROBE}="1"
+SUBSYSTEMS=="usb", ATTRS{idVendor}=="16c0", ATTRS{idProduct}=="04[789ABCD]?", GROUP+="plugdev"
+KERNEL=="ttyACM*", ATTRS{idVendor}=="16c0", ATTRS{idProduct}=="04[789B]?", GROUP+="plugdev"

nixos/modules/module-list.nix

@@ -41,6 +41,7 @@
   ./hardware/pcmcia.nix
   ./hardware/raid/hpsa.nix
   ./hardware/usb-wwan.nix
+  ./hardware/onlykey.nix
   ./hardware/video/amdgpu.nix
   ./hardware/video/amdgpu-pro.nix
   ./hardware/video/ati.nix