dt-bindings: phy: Add UniPhier AHCI PHY description

Add DT bindings for PHY interface built into ahci controller implemented
in UniPhier SoCs.
Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/1598352071-26675-2-git-send-email-hayashi.kunihiko@socionext.comSigned-off-by: Vinod Koul <vkoul@kernel.org>

Documentation/devicetree/bindings/phy/socionext,uniphier-ahci-phy.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/phy/socionext,uniphier-ahci-phy.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Socionext UniPhier AHCI PHY
+
+description: |
+  This describes the deivcetree bindings for PHY interfaces built into
+  AHCI controller implemented on Socionext UniPhier SoCs.
+
+maintainers:
+  - Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
+
+properties:
+  compatible:
+    enum:
+      - socionext,uniphier-pxs2-ahci-phy
+      - socionext,uniphier-pxs3-ahci-phy
+
+  reg:
+    description: PHY register region (offset and length)
+
+  "#phy-cells":
+    const: 0
+
+  clocks:
+    maxItems: 2
+
+  clock-names:
+    oneOf:
+      - items:          # for PXs2
+        - const: link
+      - items:          # for others
+        - const: link
+        - const: phy
+
+  resets:
+    maxItems: 2
+
+  reset-names:
+    items:
+      - const: link
+      - const: phy
+
+required:
+  - compatible
+  - reg
+  - "#phy-cells"
+  - clocks
+  - clock-names
+  - resets
+  - reset-names
+
+additionalProperties: false
+
+examples:
+  - |
+    ahci-glue@65700000 {
+        compatible = "socionext,uniphier-pxs3-ahci-glue",
+                     "simple-mfd";
+        #address-cells = <1>;
+        #size-cells = <1>;
+        ranges = <0 0x65700000 0x100>;
+
+        ahci_phy: phy@10 {
+            compatible = "socionext,uniphier-pxs3-ahci-phy";
+            reg = <0x10 0x10>;
+            #phy-cells = <0>;
+            clock-names = "link", "phy";
+            clocks = <&sys_clk 28>, <&sys_clk 30>;
+            reset-names = "link", "phy";
+            resets = <&sys_rst 28>, <&sys_rst 30>;
+        };
+    };