dt-bindings: phy: Add StarFive JH7110 PCIe PHY

Add StarFive JH7110 SoC PCIe 2.0 PHY dt-binding.
PCIe PHY0 (phy@10210000) can be used as USB 3.0 PHY.
Signed-off-by: Minda Chen <minda.chen@starfivetech.com>
Reviewed-by: Hal Feng <hal.feng@starfivetech.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Roger Quadros <rogerq@kernel.org>
Link: https://lore.kernel.org/r/20230629075115.11934-3-minda.chen@starfivetech.comSigned-off-by: Vinod Koul <vkoul@kernel.org>

Documentation/devicetree/bindings/phy/starfive,jh7110-pcie-phy.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/phy/starfive,jh7110-pcie-phy.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: StarFive JH7110 PCIe 2.0 PHY
+
+maintainers:
+  - Minda Chen <minda.chen@starfivetech.com>
+
+properties:
+  compatible:
+    const: starfive,jh7110-pcie-phy
+
+  reg:
+    maxItems: 1
+
+  "#phy-cells":
+    const: 0
+
+  starfive,sys-syscon:
+    $ref: /schemas/types.yaml#/definitions/phandle-array
+    items:
+      - items:
+          - description: phandle to System Register Controller sys_syscon node.
+          - description: PHY connect offset of SYS_SYSCONSAIF__SYSCFG register for USB PHY.
+    description:
+      The phandle to System Register Controller syscon node and the PHY connect offset
+      of SYS_SYSCONSAIF__SYSCFG register. Connect PHY to USB3 controller.
+
+  starfive,stg-syscon:
+    $ref: /schemas/types.yaml#/definitions/phandle-array
+    items:
+      - items:
+          - description: phandle to System Register Controller stg_syscon node.
+          - description: PHY mode offset of STG_SYSCONSAIF__SYSCFG register.
+          - description: PHY enable for USB offset of STG_SYSCONSAIF__SYSCFG register.
+    description:
+      The phandle to System Register Controller syscon node and the offset
+      of STG_SYSCONSAIF__SYSCFG register for PCIe PHY. Total 2 regsisters offset.
+
+required:
+  - compatible
+  - reg
+  - "#phy-cells"
+
+additionalProperties: false
+
+examples:
+  - |
+    phy@10210000 {
+        compatible = "starfive,jh7110-pcie-phy";
+        reg = <0x10210000 0x10000>;
+        #phy-cells = <0>;
+        starfive,sys-syscon = <&sys_syscon 0x18>;
+        starfive,stg-syscon = <&stg_syscon 0x148 0x1f4>;
+    };