dt-bindings: pinctrl: convert Broadcom Northstar to the json-schema

Important: this change converts the binding as it is. It includes
dependency on undocumented CRU that must be refactored. CRU must get
documented and offset property has to be reworked.

Above can (and will be) be handled once every CRU MFD subdevice gets
documented properly (including the pinmux).
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210421182041.22636-1-zajec5@gmail.comSigned-off-by: Linus Walleij <linus.walleij@linaro.org>

Documentation/devicetree/bindings/pinctrl/brcm,bcm4708-pinmux.txt

-Broadcom Northstar pins mux controller
-
-Some of Northstar SoCs's pins can be used for various purposes thanks to the mux
-controller. This binding allows describing mux controller and listing available
-functions. They can be referenced later by other bindings to let system
-configure controller correctly.
-
-A list of pins varies across chipsets so few bindings are available.
-
-Node of the pinmux must be nested in the CRU (Central Resource Unit) "syscon"
-noce.
-
-Required properties:
-- compatible: must be one of:
-	"brcm,bcm4708-pinmux"
-	"brcm,bcm4709-pinmux"
-	"brcm,bcm53012-pinmux"
-- offset: offset of pin registers in the CRU block
-
-Functions and their groups available for all chipsets:
-- "spi": "spi_grp"
-- "i2c": "i2c_grp"
-- "pwm": "pwm0_grp", "pwm1_grp", "pwm2_grp", "pwm3_grp"
-- "uart1": "uart1_grp"
-
-Additionally available on BCM4709 and BCM53012:
-- "mdio": "mdio_grp"
-- "uart2": "uart2_grp"
-- "sdio": "sdio_pwr_grp", "sdio_1p8v_grp"
-
-For documentation of subnodes see:
-Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt
-
-Example:
-	dmu@1800c000 {
-		compatible = "simple-bus";
-		ranges = <0 0x1800c000 0x1000>;
-		#address-cells = <1>;
-		#size-cells = <1>;
-
-		cru@100 {
-			compatible = "syscon", "simple-mfd";
-			reg = <0x100 0x1a4>;
-
-			pinctrl {
-				compatible = "brcm,bcm4708-pinmux";
-				offset = <0xc0>;
-
-				spi-pins {
-					function = "spi";
-					groups = "spi_grp";
-				};
-			};
-		};
-	};

Documentation/devicetree/bindings/pinctrl/brcm,ns-pinmux.yaml

+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/pinctrl/brcm,ns-pinmux.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Broadcom Northstar pins mux controller
+
+maintainers:
+  - Rafał Miłecki <rafal@milecki.pl>
+
+description:
+  Some of Northstar SoCs's pins can be used for various purposes thanks to the
+  mux controller. This binding allows describing mux controller and listing
+  available functions. They can be referenced later by other bindings to let
+  system configure controller correctly.
+
+  A list of pins varies across chipsets so few bindings are available.
+
+  Node of the pinmux must be nested in the CRU (Central Resource Unit) "syscon"
+  node.
+
+properties:
+  compatible:
+    enum:
+      - brcm,bcm4708-pinmux
+      - brcm,bcm4709-pinmux
+      - brcm,bcm53012-pinmux
+
+  offset:
+    description: offset of pin registers in the CRU block
+    maxItems: 1
+    $ref: /schemas/types.yaml#/definitions/uint32-array
+
+patternProperties:
+  '-pins$':
+    type: object
+    description: pin node
+    $ref: pinmux-node.yaml#
+
+    properties:
+      function:
+        enum: [ spi, i2c, pwm, uart1, mdio, uart2, sdio ]
+      groups:
+        minItems: 1
+        maxItems: 4
+        items:
+          enum: [ spi_grp, i2c_grp, pwm0_grp, pwm1_grp, pwm2_grp, pwm3_grp,
+                  uart1_grp, mdio_grp, uart2_grp, sdio_pwr_grp, sdio_1p8v_grp ]
+
+    required:
+      - function
+      - groups
+
+    additionalProperties: false
+
+allOf:
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: brcm,bcm4708-pinmux
+    then:
+      patternProperties:
+        '-pins$':
+          properties:
+            function:
+              enum: [ spi, i2c, pwm, uart1 ]
+            groups:
+              items:
+                enum: [ spi_grp, i2c_grp, pwm0_grp, pwm1_grp, pwm2_grp, pwm3_grp,
+                        uart1_grp ]
+
+required:
+  - offset
+
+additionalProperties: false
+
+examples:
+  - |
+    cru@1800c100 {
+        compatible = "syscon", "simple-mfd";
+        reg = <0x1800c100 0x1a4>;
+
+        pinctrl {
+            compatible = "brcm,bcm4708-pinmux";
+            offset = <0xc0>;
+
+            spi-pins {
+                function = "spi";
+                groups = "spi_grp";
+            };
+        };
+    };