usb: add devicetree helpers for determining dr_mode and phy_type

This adds two little devicetree helper functions for determining the
dr_mode (host, peripheral, otg) and phy_type (utmi, ulpi,...) from
the devicetree.

Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Acked-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/include/linux/usb/otg.h b/include/linux/usb/otg.h
index 291e01b..154332b 100644
--- a/include/linux/usb/otg.h
+++ b/include/linux/usb/otg.h
@@ -92,4 +92,11 @@
 /* for OTG controller drivers (and maybe other stuff) */
 extern int usb_bus_start_enum(struct usb_bus *bus, unsigned port_num);
 
+enum usb_dr_mode {
+	USB_DR_MODE_UNKNOWN,
+	USB_DR_MODE_HOST,
+	USB_DR_MODE_PERIPHERAL,
+	USB_DR_MODE_OTG,
+};
+
 #endif /* __LINUX_USB_OTG_H */