phy: add a driver for the Rockchip SoC internal USB2.0 PHY

This patch to add a generic PHY driver for ROCKCHIP usb PHYs,
currently this driver can support RK3288. The RK3288 SoC have
three independent USB PHY IPs which are all configured through a
set of registers located in the GRF (general register files)
module.

Signed-off-by: Yunzhi Li <lyz@rock-chips.com>
Tested-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
diff --git a/drivers/phy/Kconfig b/drivers/phy/Kconfig
index ccad880..b24500a 100644
--- a/drivers/phy/Kconfig
+++ b/drivers/phy/Kconfig
@@ -239,6 +239,13 @@
 	depends on OF
 	select GENERIC_PHY
 
+config PHY_ROCKCHIP_USB
+	tristate "Rockchip USB2 PHY Driver"
+	depends on ARCH_ROCKCHIP && OF
+	select GENERIC_PHY
+	help
+	  Enable this to support the Rockchip USB 2.0 PHY.
+
 config PHY_ST_SPEAR1310_MIPHY
 	tristate "ST SPEAR1310-MIPHY driver"
 	select GENERIC_PHY