phy: renesas: Add Renesas Ethernet SERDES driver for R-Car S4-8

Add Renesas Ethernet SERDES driver for R-Car S4-8 (r8a779f0).
The datasheet describes initialization procedure without any information
about registers' name/bits. So, this is all black magic to initialize
the hardware. Especially, all channels should be initialized at once.
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Link: https://lore.kernel.org/r/20221108005500.3011449-3-yoshihiro.shimoda.uh@renesas.comSigned-off-by: Vinod Koul <vkoul@kernel.org>

drivers/phy/renesas/Kconfig

@@ -2,6 +2,14 @@
 #
 # Phy drivers for Renesas platforms
 #
+# NOTE: Please sorted config names alphabetically.
+config PHY_R8A779F0_ETHERNET_SERDES
+	tristate "Renesas R-Car S4-8 Ethernet SERDES driver"
+	depends on ARCH_RENESAS || COMPILE_TEST
+	select GENERIC_PHY
+	help
+	  Support for Ethernet SERDES found on Renesas R-Car S4-8 SoCs.
+
 config PHY_RCAR_GEN2
 	tristate "Renesas R-Car generation 2 USB PHY driver"
 	depends on ARCH_RENESAS

drivers/phy/renesas/Makefile

 # SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_PHY_R8A779F0_ETHERNET_SERDES)	+= r8a779f0-ether-serdes.o
 obj-$(CONFIG_PHY_RCAR_GEN2)		+= phy-rcar-gen2.o
 obj-$(CONFIG_PHY_RCAR_GEN3_PCIE)	+= phy-rcar-gen3-pcie.o
 obj-$(CONFIG_PHY_RCAR_GEN3_USB2)	+= phy-rcar-gen3-usb2.o