usb: phy: add a new driver for usb3 phy

Added a driver for usb3 phy that handles the interaction between usb phy
device and dwc3 controller.

This also includes device tree support for usb3 phy driver and
the documentation with device tree binding information is updated.

Currently writing to control module register is taken care in this
driver which will be removed once the control module driver is in place.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Moiz Sonasath <m-sonasath@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

Documentation/devicetree/bindings/usb/usb-phy.txt

@@ -17,3 +17,26 @@ usb2phy@4a0ad080 {
 	reg = <0x4a0ad080 0x58>;
 	ctrl-module = <&omap_control_usb>;
 };
+
+OMAP USB3 PHY
+
+Required properties:
+ - compatible: Should be "ti,omap-usb3"
+ - reg : Address and length of the register set for the device.
+ - reg-names: The names of the register addresses corresponding to the registers
+   filled in "reg".
+
+Optional properties:
+ - ctrl-module : phandle of the control module used by PHY driver to power on
+   the PHY.
+
+This is usually a subnode of ocp2scp to which it is connected.
+
+usb3phy@4a084400 {
+	compatible = "ti,omap-usb3";
+	reg = <0x4a084400 0x80>,
+	      <0x4a084800 0x64>,
+	      <0x4a084c00 0x40>;
+	reg-names = "phy_rx", "phy_tx", "pll_ctrl";
+	ctrl-module = <&omap_control_usb>;
+};

drivers/usb/phy/Kconfig

@@ -15,6 +15,16 @@ config OMAP_USB2
 	  The USB OTG controller communicates with the comparator using this
 	  driver.
 
+config OMAP_USB3
+	tristate "OMAP USB3 PHY Driver"
+	select USB_OTG_UTILS
+	select OMAP_CONTROL_USB
+	help
+	  Enable this to support the USB3 PHY that is part of SOC. This
+	  driver takes care of all the PHY functionality apart from comparator.
+	  This driver interacts with the "OMAP Control USB Driver" to power
+	  on/off the PHY.
+
 config OMAP_CONTROL_USB
 	tristate "OMAP CONTROL USB Driver"
 	depends on ARCH_OMAP2PLUS

drivers/usb/phy/Makefile

@@ -5,6 +5,7 @@
 ccflags-$(CONFIG_USB_DEBUG) := -DDEBUG
 
 obj-$(CONFIG_OMAP_USB2)			+= omap-usb2.o
+obj-$(CONFIG_OMAP_USB3)			+= omap-usb3.o
 obj-$(CONFIG_OMAP_CONTROL_USB)		+= omap-control-usb.o
 obj-$(CONFIG_USB_ISP1301)		+= isp1301.o
 obj-$(CONFIG_MV_U3D_PHY)		+= mv_u3d_phy.o