usb: musb: Add support for MediaTek musb controller

This adds support for MediaTek musb controller in
host, peripheral and otg mode.
There are some quirk of MediaTek musb controller, such as:
 -W1C interrupt status registers
 -Private data toggle registers
 -No dedicated DMA interrupt line
Signed-off-by: Min Guo <min.guo@mediatek.com>
Signed-off-by: Yonglong Wu <yonglong.wu@mediatek.com>
Signed-off-by: Bin Liu <b-liu@ti.com>
Link: https://lore.kernel.org/r/20200115132547.364-24-b-liu@ti.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/musb/Kconfig

@@ -115,6 +115,13 @@ config USB_MUSB_JZ4740
 	depends on USB_MUSB_GADGET
 	depends on USB=n || USB_OTG_BLACKLIST_HUB
 
+config USB_MUSB_MEDIATEK
+	tristate "MediaTek platforms"
+	depends on ARCH_MEDIATEK || COMPILE_TEST
+	depends on NOP_USB_XCEIV
+	depends on GENERIC_PHY
+	select USB_ROLE_SWITCH
+
 config USB_MUSB_AM335X_CHILD
 	tristate
 
@@ -141,7 +148,7 @@ config USB_UX500_DMA
 
 config USB_INVENTRA_DMA
 	bool 'Inventra'
-	depends on USB_MUSB_OMAP2PLUS
+	depends on USB_MUSB_OMAP2PLUS || USB_MUSB_MEDIATEK
 	help
 	  Enable DMA transfers using Mentor's engine.
 

drivers/usb/musb/Makefile

@@ -24,6 +24,7 @@ obj-$(CONFIG_USB_MUSB_DA8XX)			+= da8xx.o
 obj-$(CONFIG_USB_MUSB_UX500)			+= ux500.o
 obj-$(CONFIG_USB_MUSB_JZ4740)			+= jz4740.o
 obj-$(CONFIG_USB_MUSB_SUNXI)			+= sunxi.o
+obj-$(CONFIG_USB_MUSB_MEDIATEK)      		+= mediatek.o
 
 
 obj-$(CONFIG_USB_MUSB_AM335X_CHILD)		+= musb_am335x.o