arm64: dts: ti: k3-j721s2-common-proc-board: Enable SERDES0

Configure first lane to PCIe, the second lane to USB and the last two lanes
to eDP. Also, add sub-nodes to SERDES0 DT node to represent SERDES0 is
connected to PCIe.
Signed-off-by: Aswath Govindraju <a-govindraju@ti.com>
Signed-off-by: Matt Ranostay <mranostay@ti.com>
Signed-off-by: Ravi Gunasekaran <r-gunasekaran@ti.com>
Reviewed-by: Roger Quadros <rogerq@kernel.org>
Link: https://lore.kernel.org/r/20230331090028.8373-5-r-gunasekaran@ti.comSigned-off-by: Vignesh Raghavendra <vigneshr@ti.com>

arch/arm64/boot/dts/ti/k3-j721s2-common-proc-board.dts

@@ -9,6 +9,9 @@
 
 #include "k3-j721s2-som-p0.dtsi"
 #include <dt-bindings/net/ti-dp83867.h>
+#include <dt-bindings/phy/phy-cadence.h>
+#include <dt-bindings/phy/phy.h>
+#include <dt-bindings/mux/ti-serdes.h>
 
 / {
 	compatible = "ti,j721s2-evm", "ti,j721s2";
@@ -321,6 +324,26 @@ &cpsw_port1 {
 	phy-handle = <&phy0>;
 };
 
+&serdes_ln_ctrl {
+	idle-states = <J721S2_SERDES0_LANE0_PCIE1_LANE0>, <J721S2_SERDES0_LANE1_USB>,
+		      <J721S2_SERDES0_LANE2_EDP_LANE2>, <J721S2_SERDES0_LANE3_EDP_LANE3>;
+};
+
+&serdes_refclk {
+	clock-frequency = <100000000>;
+};
+
+&serdes0 {
+	status = "okay";
+	serdes0_pcie_link: phy@0 {
+		reg = <0>;
+		cdns,num-lanes = <1>;
+		#phy-cells = <0>;
+		cdns,phy-type = <PHY_TYPE_PCIE>;
+		resets = <&serdes_wiz0 1>;
+	};
+};
+
 &mcu_mcan0 {
 	status = "okay";
 	pinctrl-names = "default";