dt-bindings: phy: Add Spacemit K3 USB3/PCIe comb phy support

The USB3/PCIe comb PHY on the K3 is a complex PHY group that
can provide multiple phy for both PCIe and USB controller.
Its mux configuration is controlled by the APMU syscon device.

Signed-off-by: Inochi Amaoto <inochiama@gmail.com>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://patch.msgid.link/20260703021024.495433-2-inochiama@gmail.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

Documentation/devicetree/bindings/phy/spacemit,k3-combo-phy.yaml

@@ -0,0 +1,68 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/phy/spacemit,k3-combo-phy.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Spacemit K3 PCIE/USB3 Comb PHY
+
+maintainers:
+  - Inochi Amaoto <inochiama@gmail.com>
+
+properties:
+  compatible:
+    const: spacemit,k3-combo-phy
+
+  reg:
+    maxItems: 1
+
+  "#phy-cells":
+    const: 2
+    description:
+      The first one is phy id, the second one is phy type. This
+      only supports types are PCIe and USB .
+
+  spacemit,apb-spare:
+    $ref: /schemas/types.yaml#/definitions/phandle
+    description:
+      Phandle to APB SPARE system controller interface, used for
+      PHY calibration.
+
+  spacemit,apmu:
+    $ref: /schemas/types.yaml#/definitions/phandle-array
+    items:
+      - items:
+          - description: phandle of APMU syscon
+          - description: configuration of the PHY lanes
+    description: |
+      Phandle to control PHY mux configuration. The configuration
+      is described as follows:
+      bit 4: 0 - PCIe A x8 mode, 1 - PCIe lane share mode
+      bit 3: 0 - PCIe A x4 mode, 1 - PCIe A x2 and PCIe B x2 mode
+      bit 2: 0 - PCIe C lane 0 is PCIe mode , 1 - USB mode
+      bit 1: 0 - PCIe C lane 1 is PCIe mode , 1 - USB mode
+      bit 0: 0 - PCIe D lane is PCIe mode , 1 - USB mode
+
+      The bit[3:0] is only valid when bit 4 is 1.
+
+      This mux control does not affect the PHY for PCIe E, it is always
+      in PCIe mode.
+
+required:
+  - compatible
+  - reg
+  - "#phy-cells"
+  - spacemit,apb-spare
+  - spacemit,apmu
+
+additionalProperties: false
+
+examples:
+  - |
+    phy@81d00000 {
+      compatible = "spacemit,k3-combo-phy";
+      reg = <0x81d00000 0x600000>;
+      #phy-cells = <2>;
+      spacemit,apb-spare = <&apb_spare>;
+      spacemit,apmu = <&apmu 0x00>;
+    };