Add an initial stab at a GD32 mcu support driver

src/kaleidoscope/driver/mcu/GD32.h

@@ -0,0 +1,51 @@
+/* -*- mode: c++ -*-
+ * driver::MCU::GD32 -- GD32 MCU driver for Kaleidoscope, initially targeting the GD32F303 series
+ * Copyright (C) 2019, 2020  Keyboard.io, Inc
+ *
+ * This program is free software: you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License as published by the Free Software
+ * Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include "kaleidoscope/driver/mcu/Base.h"  // for Base, BaseProps
+
+namespace kaleidoscope {
+namespace driver {
+namespace mcu {
+
+struct GD32Props : public kaleidoscope::driver::mcu::BaseProps {
+};
+
+#ifndef KALEIDOSCOPE_VIRTUAL_BUILD
+template<typename _Props>
+class GD32 : public kaleidoscope::driver::mcu::Base<_Props> {
+ public:
+  void detachFromHost() {
+    USBCore::disconnect();
+  }
+  void attachToHost() {
+    USBCore::connect();
+  }
+
+
+  void setup() {
+  }
+};
+#else
+template<typename _Props>
+class GD32 : public kaleidoscope::driver::mcu::Base<_Props> {};
+#endif  // ifndef KALEIDOSCOPE_VIRTUAL_BUILD
+
+}  // namespace mcu
+}  // namespace driver
+}  // namespace kaleidoscope