Bluetooth: mediatek: Add protocol support for MediaTek serial devices

This adds a driver based on serdev driver for the MediaTek serial protocol
based on running H:4, which can enable the built-in Bluetooth device inside
MT7622 SoC.
Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

drivers/bluetooth/Kconfig

@@ -365,6 +365,17 @@ config BT_WILINK
 	  Say Y here to compile support for Texas Instrument's WiLink7 driver
 	  into the kernel or say M to compile it as module (btwilink).
 
+config BT_MTKUART
+	tristate "MediaTek HCI UART driver"
+	depends on SERIAL_DEV_BUS
+	help
+	  MediaTek Bluetooth HCI UART driver.
+	  This driver is required if you want to use MediaTek Bluetooth
+	  with serial interface.
+
+	  Say Y here to compile support for MediaTek Bluetooth UART devices
+	  into the kernel or say M to compile it as module (btmtkuart).
+
 config BT_QCOMSMD
 	tristate "Qualcomm SMD based HCI support"
 	depends on RPMSG || (COMPILE_TEST && RPMSG=n)

drivers/bluetooth/Makefile

@@ -20,6 +20,7 @@ obj-$(CONFIG_BT_ATH3K)		+= ath3k.o
 obj-$(CONFIG_BT_MRVL)		+= btmrvl.o
 obj-$(CONFIG_BT_MRVL_SDIO)	+= btmrvl_sdio.o
 obj-$(CONFIG_BT_WILINK)		+= btwilink.o
+obj-$(CONFIG_BT_MTKUART)	+= btmtkuart.o
 obj-$(CONFIG_BT_QCOMSMD)	+= btqcomsmd.o
 obj-$(CONFIG_BT_BCM)		+= btbcm.o
 obj-$(CONFIG_BT_RTL)		+= btrtl.o