dt-bindings:iio:potentiometer:microchip,mcp41010 txt to yaml conversion

A simple binding that I almost just move to trivial devices.
The small amount of additional documentation and relatively large number
of compatible entries convinced me to suggest we keep this one separately
documented.
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Cc: Chris Coffey <cmc@babblebit.net>
Link: https://lore.kernel.org/r/20201031184854.745828-5-jic23@kernel.org

Documentation/devicetree/bindings/iio/potentiometer/mcp41010.txt

-* Microchip MCP41010/41050/41100/42010/42050/42100 Digital Potentiometer
-
-Datasheet publicly available at:
-https://ww1.microchip.com/downloads/en/devicedoc/11195c.pdf
-
-The node for this driver must be a child node of a SPI controller, hence
-all mandatory properties described in
-
-        Documentation/devicetree/bindings/spi/spi-bus.txt
-
-must be specified.
-
-Required properties:
-	- compatible:  	Must be one of the following, depending on the
-			model:
-			"microchip,mcp41010"
-			"microchip,mcp41050"
-			"microchip,mcp41100"
-			"microchip,mcp42010"
-			"microchip,mcp42050"
-			"microchip,mcp42100"
-
-Example:
-potentiometer@0 {
-	compatible = "microchip,mcp41010";
-	reg = <0>;
-	spi-max-frequency = <500000>;
-};

Documentation/devicetree/bindings/iio/potentiometer/microchip,mcp41010.yaml

+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/potentiometer/microchip,mcp41010.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Microchip MCP41010/41050/41100/42010/42050/42100 Digital Potentiometer
+
+maintainers:
+  - Chris Coffey <cmc@babblebit.net>
+
+description: |
+  Datasheet: https://ww1.microchip.com/downloads/en/devicedoc/11195c.pdf
+
+properties:
+  compatible:
+    enum:
+      - microchip,mcp41010
+      - microchip,mcp41050
+      - microchip,mcp41100
+      - microchip,mcp42010
+      - microchip,mcp42050
+      - microchip,mcp42100
+
+  reg:
+    maxItems: 1
+
+  spi-max-frequency: true
+
+additionalProperties: false
+
+required:
+  - compatible
+  - reg
+
+examples:
+  - |
+    spi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        potentiometer@0 {
+            compatible = "microchip,mcp41010";
+            reg = <0>;
+            spi-max-frequency = <500000>;
+        };
+    };
+...