dt-bindings: pinctrl: mvebu: Document bindings for AC5

Add JSON schema for marvell,ac5-pinctrl present on the Marvell 98DX2530
SoC.
Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220414233055.586962-2-chris.packham@alliedtelesis.co.nzSigned-off-by: Linus Walleij <linus.walleij@linaro.org>

Documentation/devicetree/bindings/pinctrl/marvell,ac5-pinctrl.yaml

+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/pinctrl/marvell,ac5-pinctrl.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Marvell AC5 pin controller
+
+maintainers:
+  - Chris Packham <chris.packham@alliedtelesis.co.nz>
+
+description:
+  Bindings for Marvell's AC5 memory-mapped pin controller.
+
+properties:
+  compatible:
+    items:
+      - const: marvell,ac5-pinctrl
+
+  reg:
+    maxItems: 1
+
+patternProperties:
+  '-pins$':
+    type: object
+    $ref: pinmux-node.yaml#
+
+    properties:
+      marvell,function:
+        $ref: "/schemas/types.yaml#/definitions/string"
+        description:
+          Indicates the function to select.
+        enum: [ dev_init_done, ge, gpio, i2c0, i2c1, int_out, led, nand, pcie, ptp, sdio,
+                spi0, spi1, synce, tsen_int, uart0, uart1, uart2, uart3, uartsd, wd_int, xg ]
+
+      marvell,pins:
+        $ref: /schemas/types.yaml#/definitions/string-array
+        description:
+          Array of MPP pins to be used for the given function.
+        minItems: 1
+        items:
+          enum: [ mpp0, mpp1, mpp2, mpp3, mpp4, mpp5, mpp6, mpp7, mpp8, mpp9,
+                  mpp10, mpp11, mpp12, mpp13, mpp14, mpp15, mpp16, mpp17, mpp18, mpp19,
+                  mpp20, mpp21, mpp22, mpp23, mpp24, mpp25, mpp26, mpp27, mpp28, mpp29,
+                  mpp30, mpp31, mpp32, mpp33, mpp34, mpp35, mpp36, mpp37, mpp38, mpp39,
+                  mpp40, mpp41, mpp42, mpp43, mpp44, mpp45 ]
+
+allOf:
+  - $ref: "pinctrl.yaml#"
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    pinctrl@80020100 {
+      compatible = "marvell,ac5-pinctrl";
+      reg = <0x80020100 0x20>;
+
+      i2c0_pins: i2c0-pins {
+        marvell,pins = "mpp26", "mpp27";
+        marvell,function = "i2c0";
+      };
+
+      i2c0_gpio: i2c0-gpio-pins {
+        marvell,pins = "mpp26", "mpp27";
+        marvell,function = "gpio";
+      };
+    };