stm32g4: Add support for USB

Co-authored-by: Ben Brewer <ben.brewer@codethink.co.uk>

include/libopencm3/stm32/g4/st_usbfs.h

@@ -0,0 +1,27 @@
+/*
+ * This file is part of the libopencm3 project.
+ *
+ * This library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This library 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 Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library.  If not, see <http://www.gnu.org/licenses/>.
+ */
+/* THIS FILE SHOULD NOT BE INCLUDED DIRECTLY !
+ * Use top-level <libopencm3/stm32/st_usbfs.h>
+ */
+
+#ifndef LIBOPENCM3_ST_USBFS_H
+#	error Do not include directly !
+#else
+
+#include <libopencm3/stm32/common/st_usbfs_v2.h>
+
+#endif

include/libopencm3/stm32/st_usbfs.h

@@ -35,6 +35,8 @@
 #       include <libopencm3/stm32/l1/st_usbfs.h>
 #elif defined(STM32L4)
 #       include <libopencm3/stm32/l4/st_usbfs.h>
+#elif defined(STM32G4)
+#       include <libopencm3/stm32/g4/st_usbfs.h>
 #else
 #       error "STM32 family not defined or not supported."
 #endif

lib/stm32/g4/Makefile

@@ -44,6 +44,10 @@ OBJS += pwr.o
 OBJS += rcc.o rcc_common_all.o
 OBJS += timer_common_all.o timer_common_f0234.o
 
+OBJS += usb.o usb_control.o usb_standard.o usb_msc.o
+OBJS += usb_hid.o
+OBJS += st_usbfs_core.o st_usbfs_v2.o
+
 VPATH += ../../usb:../:../../cm3:../common
 VPATH += ../../ethernet