dt-bindings: i2c: Convert i2c-pxa to json-schema

A conversion of the i2c-pxa binding to DT schema format using json-schema.

This also cleans ups some errors in the binding: The compatible string
description suggested that "mmp" in "mrvl,mmp-twsi" is to be substituted
with a processor model, which wouldn't be a right thing to do and indeed
nobody seems to have been doing that. There also was "Recommended
properties" section that included optional as well as mandatory
properties. Missing mandatory properties were added to the example.
Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Link: https://lore.kernel.org/r/20200616223353.993567-3-lkundrak@v3.skSigned-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/i2c/i2c-pxa.txt

-* Marvell MMP I2C controller
-
-Required properties :
-
- - reg : Offset and length of the register set for the device
- - compatible : should be "mrvl,mmp-twsi" where mmp is the name of a
-   compatible processor, e.g. pxa168, pxa910, mmp2, mmp3.
-   For the pxa2xx/pxa3xx, an additional node "mrvl,pxa-i2c" is required
-   as shown in the example below.
-   For the Armada 3700, the compatible should be "marvell,armada-3700-i2c".
-
-Recommended properties :
-
- - interrupts : the interrupt number
- - mrvl,i2c-polling : Disable interrupt of i2c controller. Polling
-   status register of i2c controller instead.
- - mrvl,i2c-fast-mode : Enable fast mode of i2c controller.
-
-Examples:
-	twsi1: i2c@d4011000 {
-		compatible = "mrvl,mmp-twsi";
-		reg = <0xd4011000 0x1000>;
-		interrupts = <7>;
-		mrvl,i2c-fast-mode;
-	};
-	
-	twsi2: i2c@d4025000 {
-		compatible = "mrvl,mmp-twsi";
-		reg = <0xd4025000 0x1000>;
-		interrupts = <58>;
-	};

Documentation/devicetree/bindings/i2c/i2c-pxa.yaml

+# SPDX-License-Identifier: GPL-2.0-only
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/i2c/i2c-pxa.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Marvell MMP I2C controller bindings
+
+maintainers:
+  - Rob Herring <robh+dt@kernel.org>
+
+allOf:
+  - $ref: /schemas/i2c/i2c-controller.yaml#
+  - if:
+      not:
+        required:
+          - mrvl,i2c-polling
+    then:
+        required:
+          - interrupts
+
+properties:
+  compatible:
+    enum:
+      - mrvl,mmp-twsi
+      - mrvl,pxa-i2c
+      - marvell,armada-3700-i2c
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    minItems: 1
+
+  resets:
+    minItems: 1
+
+  mrvl,i2c-polling:
+    $ref: /schemas/types.yaml#/definitions/flag
+    description: |
+      Disable interrupt of i2c controller. Polling status register of i2c
+      controller instead.
+
+  mrvl,i2c-fast-mode:
+    $ref: /schemas/types.yaml#/definitions/flag
+    description: Enable fast mode of i2c controller.
+
+unevaluatedProperties: false
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+  - '#address-cells'
+  - '#size-cells'
+
+examples:
+  - |
+    #include <dt-bindings/clock/marvell,mmp2.h>
+    i2c@d4011000 {
+        compatible = "mrvl,mmp-twsi";
+        reg = <0xd4011000 0x1000>;
+        interrupts = <7>;
+        clocks = <&soc_clocks MMP2_CLK_TWSI1>;
+        mrvl,i2c-fast-mode;
+        #address-cells = <1>;
+        #size-cells = <0>;
+    };
+
+...