phy: realtek: usb: add new driver for the Realtek RTD SoC USB 2.0 PHY

Realtek DHC (digital home center) RTD SoCs support DWC3 XHCI USB
controller. Added the driver to drive the USB 2.0 PHY transceivers.

Note: New driver,remove the port status notification on legacy USB PHY.
Use the generic PHY to notify the usb device connect and disconnect.
To avoid using these PHYs would require describing the very same
PHY using both the generic "phy" property and the deprecated "usb-phy"
property.

Signed-off-by: Stanley Chang <stanley_chang@realtek.com>
Link: https://lore.kernel.org/r/20231213031203.4911-2-stanley_chang@realtek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/phy/Kconfig

@@ -87,6 +87,7 @@ source "drivers/phy/motorola/Kconfig"
 source "drivers/phy/mscc/Kconfig"
 source "drivers/phy/qualcomm/Kconfig"
 source "drivers/phy/ralink/Kconfig"
+source "drivers/phy/realtek/Kconfig"
 source "drivers/phy/renesas/Kconfig"
 source "drivers/phy/rockchip/Kconfig"
 source "drivers/phy/samsung/Kconfig"

drivers/phy/Makefile

@@ -26,6 +26,7 @@ obj-y					+= allwinner/	\
 					   mscc/	\
 					   qualcomm/	\
 					   ralink/	\
+					   realtek/	\
 					   renesas/	\
 					   rockchip/	\
 					   samsung/	\

drivers/phy/realtek/Kconfig

@@ -0,0 +1,20 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Phy drivers for Realtek platforms
+#
+
+if ARCH_REALTEK || COMPILE_TEST
+
+config PHY_RTK_RTD_USB2PHY
+	tristate "Realtek RTD USB2 PHY Transceiver Driver"
+	depends on USB_SUPPORT
+	select GENERIC_PHY
+	select USB_PHY
+	select USB_COMMON
+	help
+	  Enable this to support Realtek SoC USB2 phy transceiver.
+	  The DHC (digital home center) RTD series SoCs used the Synopsys
+	  DWC3 USB IP. This driver will do the PHY initialization
+	  of the parameters.
+
+endif # ARCH_REALTEK || COMPILE_TEST

drivers/phy/realtek/Makefile

@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_PHY_RTK_RTD_USB2PHY)	+= phy-rtk-usb2.o