usb: otg: Add ulpi viewport access ops

Add generic access ops for controllers with a ulpi viewport register
(e.g. Chipidea/ARC based controllers).

Signed-off-by: Benoit Goby <benoit@android.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/otg/Kconfig b/drivers/usb/otg/Kconfig
index ceb24fe..daf3e5f 100644
--- a/drivers/usb/otg/Kconfig
+++ b/drivers/usb/otg/Kconfig
@@ -49,6 +49,13 @@
 	  Enable this to support ULPI connected USB OTG transceivers which
 	  are likely found on embedded boards.
 
+config USB_ULPI_VIEWPORT
+	bool
+	depends on USB_ULPI
+	help
+	  Provides read/write operations to the ULPI phy register set for
+	  controllers with a viewport register (e.g. Chipidea/ARC controllers).
+
 config TWL4030_USB
 	tristate "TWL4030 USB Transceiver Driver"
 	depends on TWL4030_CORE && REGULATOR_TWL4030