dt-bindings: iio: potentiometer: add max5432.yaml binding

Add a binding for the Maxim Integrated MAX5432-MAX5435 family of digital
potentiometers.
Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/devicetree/bindings/iio/potentiometer/max5432.yaml

+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/potentiometer/max5432.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Maxim Integrated MAX5432-MAX5435 Digital Potentiometers
+
+maintainers:
+  - Martin Kaiser <martin@kaiser.cx>
+
+description: |
+  Maxim Integrated MAX5432-MAX5435 Digital Potentiometers connected via I2C
+
+  Datasheet:
+    https://datasheets.maximintegrated.com/en/ds/MAX5432-MAX5435.pdf
+
+properties:
+  compatible:
+    enum:
+      - maxim,max5432
+      - maxim,max5433
+      - maxim,max5434
+      - maxim,max5435
+
+  reg:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    i2c {
+      #address-cells = <1>;
+      #size-cells = <0>;
+      max5434@28 {
+        compatible = "maxim,max5434";
+        reg = <0x28>;
+      };
+    };