usb: dwc2: Update Kconfig to support dual-role

Update DWC2 kconfig and makefile to support dual-role mode. The platform
file will always get compiled for the case where the controller is directly
connected to the CPU. So for loadable modules, only dwc2.ko is needed.
Signed-off-by: Dinh Nguyen <dinguyen@opensource.altera.com>
Acked-by: Paul Zimmerman <paulz@synopsys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/dwc2/Kconfig

 config USB_DWC2
-	bool "DesignWare USB2 DRD Core Support"
+	tristate "DesignWare USB2 DRD Core Support"
 	depends on USB
 	help
 	  Say Y here if your system has a Dual Role Hi-Speed USB
 	  controller based on the DesignWare HSOTG IP Core.
 
-	  For host mode, if you choose to build the driver as dynamically
-	  linked modules, the core module will be called dwc2.ko, the PCI
-	  bus interface module (if you have a PCI bus system) will be
-	  called dwc2_pci.ko, and the platform interface module (for
-	  controllers directly connected to the CPU) will be called
-	  dwc2_platform.ko. For gadget mode, there will be a single
-	  module called dwc2_gadget.ko.
-
-	  NOTE: The s3c-hsotg driver is now renamed to dwc2_gadget. The
-	  host and gadget drivers are still currently separate drivers.
-	  There are plans to merge the dwc2_gadget driver with the dwc2
-	  host driver in the near future to create a dual-role driver.
+	  If you choose to build the driver as dynamically
+	  linked modules, a single dwc2.ko(regardless of mode of operation)
+	  will get built for both platform IPs and PCI.
 
 if USB_DWC2
 
+choice
+	bool "DWC2 Mode Selection"
+	default USB_DWC2_DUAL_ROLE if (USB && USB_GADGET)
+	default USB_DWC2_HOST if (USB && !USB_GADGET)
+	default USB_DWC2_PERIPHERAL if (!USB && USB_GADGET)
+
 config USB_DWC2_HOST
-	tristate "Host only mode"
+	bool "Host only mode"
 	depends on USB
 	help
 	  The Designware USB2.0 high-speed host controller
-	  integrated into many SoCs.
-
-config USB_DWC2_PLATFORM
-	bool "DWC2 Platform"
-	depends on USB_DWC2_HOST
-	default USB_DWC2_HOST
-	help
-	  The Designware USB2.0 platform interface module for
-	  controllers directly connected to the CPU. This is only
-	  used for host mode.
+	  integrated into many SoCs. Select this option if you want the
+	  driver to operate in Host-only mode.
 
 config USB_DWC2_PCI
 	bool "DWC2 PCI"
@@ -47,11 +36,31 @@ config USB_DWC2_PCI
 comment "Gadget mode requires USB Gadget support to be enabled"
 
 config USB_DWC2_PERIPHERAL
-	tristate "Gadget only mode"
-	depends on USB_GADGET
+	bool "Gadget only mode"
+	depends on USB_GADGET=y || USB_GADGET=USB_DWC2
 	help
 	  The Designware USB2.0 high-speed gadget controller
-	  integrated into many SoCs.
+	  integrated into many SoCs. Select this option if you want the
+	  driver to operate in Peripheral-only mode. This option requires
+	  USB_GADGET=y.
+
+config USB_DWC2_DUAL_ROLE
+	bool "Dual Role mode"
+	depends on ((USB=y || USB=USB_DWC2) && (USB_GADGET=y || USB_GADGET=USB_DWC2))
+	help
+	  Select this option if you want the driver to work in a dual-role
+	  mode. In this mode both host and gadget features are enabled, and
+	  the role will be determined by the cable that gets plugged-in. This
+	  option requires USB_GADGET=y.
+endchoice
+
+config USB_DWC2_PLATFORM
+	bool
+        depends on !PCI
+        default y
+        help
+          The Designware USB2.0 platform interface module for
+          controllers directly connected to the CPU.
 
 config USB_DWC2_DEBUG
 	bool "Enable Debugging Messages"

drivers/usb/dwc2/Makefile

 ccflags-$(CONFIG_USB_DWC2_DEBUG)	+= -DDEBUG
 ccflags-$(CONFIG_USB_DWC2_VERBOSE)	+= -DVERBOSE_DEBUG
 
-obj-$(CONFIG_USB_DWC2_HOST)		+= dwc2.o
+obj-$(CONFIG_USB_DWC2)			+= dwc2.o
 dwc2-y					:= core.o core_intr.o
-dwc2-y					+= hcd.o hcd_intr.o
-dwc2-y					+= hcd_queue.o hcd_ddma.o
+
+ifneq ($(filter y,$(CONFIG_USB_DWC2_HOST) $(CONFIG_USB_DWC2_DUAL_ROLE)),)
+	dwc2-y				+= hcd.o hcd_intr.o
+	dwc2-y				+= hcd_queue.o hcd_ddma.o
+endif
+
+ifneq ($(filter y,$(CONFIG_USB_DWC2_PERIPHERAL) $(CONFIG_USB_DWC2_DUAL_ROLE)),)
+	dwc2-y       			+= gadget.o
+endif
 
 # NOTE: The previous s3c-hsotg peripheral mode only driver has been moved to
 # this location and renamed gadget.c. When building for dynamically linked
@@ -19,10 +26,4 @@ ifneq ($(CONFIG_USB_DWC2_PCI),)
 	dwc2_pci-y			:= pci.o
 endif
 
-ifneq ($(CONFIG_USB_DWC2_PLATFORM),)
-	obj-$(CONFIG_USB_DWC2_HOST)	+= dwc2_platform.o
-	dwc2_platform-y			:= platform.o
-endif
-
-obj-$(CONFIG_USB_DWC2_PERIPHERAL)	+= dwc2_gadget.o
-dwc2_gadget-y				:= gadget.o
+dwc2-$(CONFIG_USB_DWC2_PLATFORM) += platform.o