USB: serial: add uPD78F0730 USB to Serial Adaptor Driver

The adaptor can be found on development boards for 78k, RL78 and V850
microcontrollers produced by Renesas Electronics Corporation.

This is not a full-featured USB to serial converter, however it allows
basic communication and simple control which is enough for programming of
on-board flash and debugging through a debug monitor.

uPD78F0730 is a USB-enabled microcontroller with USB-to-UART conversion
implemented in firmware.

This chip is also present in some debugging adaptors which use it for
USB-to-SPI conversion as well. The present driver doesn't cover SPI,
only USB-to-UART conversion is supported.
Signed-off-by: Maksim Salau <maksim.salau@gmail.com>
Signed-off-by: Johan Hovold <johan@kernel.org>

drivers/usb/serial/Kconfig

@@ -713,6 +713,15 @@ config USB_SERIAL_QT2
 	  To compile this driver as a module, choose M here: the
 	  module will be called quatech-serial.
 
+config USB_SERIAL_UPD78F0730
+	tristate "USB Renesas uPD78F0730 Single Port Serial Driver"
+	help
+	  Say Y here if you want to use the Renesas uPD78F0730
+	  serial driver.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called upd78f0730.
+
 config USB_SERIAL_DEBUG
 	tristate "USB Debugging Device"
 	help

drivers/usb/serial/Makefile

@@ -56,6 +56,7 @@ obj-$(CONFIG_USB_SERIAL_SSU100)			+= ssu100.o
 obj-$(CONFIG_USB_SERIAL_SYMBOL)			+= symbolserial.o
 obj-$(CONFIG_USB_SERIAL_WWAN)			+= usb_wwan.o
 obj-$(CONFIG_USB_SERIAL_TI)			+= ti_usb_3410_5052.o
+obj-$(CONFIG_USB_SERIAL_UPD78F0730)		+= upd78f0730.o
 obj-$(CONFIG_USB_SERIAL_VISOR)			+= visor.o
 obj-$(CONFIG_USB_SERIAL_WISHBONE)		+= wishbone-serial.o
 obj-$(CONFIG_USB_SERIAL_WHITEHEAT)		+= whiteheat.o