dt-bindings: hwmon: Add bindings for Winbond W83781D

This adds a device tree binding for the Winbond W83781D and its
sibling HW monitoring ICs. This is used in for example the Freecom
FSG-3 router/NAS.

Cc: devicetree@vger.kernel.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210729230543.2853485-1-linus.walleij@linaro.orgSigned-off-by: Guenter Roeck <linux@roeck-us.net>

Documentation/devicetree/bindings/hwmon/winbond,w83781d.yaml

+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+
+$id: http://devicetree.org/schemas/hwmon/winbond,w83781d.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Winbond W83781 and compatible hardware monitor IC
+
+maintainers:
+  - Linus Walleij <linus.walleij@linaro.org>
+
+properties:
+  compatible:
+    enum:
+      - winbond,w83781d
+      - winbond,w83781g
+      - winbond,w83782d
+      - winbond,w83783s
+      - asus,as99127f
+
+  reg:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        temperature-sensor@28 {
+            compatible = "winbond,w83781d";
+            reg = <0x28>;
+        };
+    };