dt-bindings: phy: renesas: Document Renesas Ethernet SERDES

Document Renesas Etherent SERDES for R-Car S4-8 (r8a779f0).
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20221108005500.3011449-2-yoshihiro.shimoda.uh@renesas.comSigned-off-by: Vinod Koul <vkoul@kernel.org>

Documentation/devicetree/bindings/phy/renesas,r8a779f0-ether-serdes.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/phy/renesas,r8a779f0-ether-serdes.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Renesas Ethernet SERDES
+
+maintainers:
+  - Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
+
+properties:
+  compatible:
+    const: renesas,r8a779f0-ether-serdes
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  resets:
+    maxItems: 1
+
+  power-domains:
+    maxItems: 1
+
+  '#phy-cells':
+    description: Port number of SERDES.
+    const: 1
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - resets
+  - power-domains
+  - '#phy-cells'
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/r8a779f0-cpg-mssr.h>
+    #include <dt-bindings/power/r8a779f0-sysc.h>
+
+    phy@e6444000 {
+        compatible = "renesas,r8a779f0-ether-serdes";
+        reg = <0xe6444000 0xc00>;
+        clocks = <&cpg CPG_MOD 1506>;
+        power-domains = <&sysc R8A779F0_PD_ALWAYS_ON>;
+        resets = <&cpg 1506>;
+        #phy-cells = <1>;
+    };