dt-bindings: iio: humidity: Add TI HDC302x support

Add device tree bindings for HDC3020/HDC3021/HDC3022 humidity and
temperature sensors.

Signed-off-by: Li peiyu <[e-mail]>
Reviewed-by: Conor Dooley <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jonathan Cameron <[e-mail]>

Documentation/devicetree/bindings/iio/humidity/ti,hdc3020.yaml

···
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/humidity/ti,hdc3020.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: HDC3020/HDC3021/HDC3022 humidity and temperature iio sensors
+
+maintainers:
+  - Li peiyu <[e-mail]>
+  - Javier Carrasco <[e-mail]>
+
+description:
+  https://www.ti.com/lit/ds/symlink/hdc3020.pdf
+
+  The HDC302x is an integrated capacitive based relative humidity (RH)
+  and temperature sensor.
+
+properties:
+  compatible:
+    oneOf:
+      - items:
+          - enum:
+              - ti,hdc3021
+              - ti,hdc3022
+          - const: ti,hdc3020
+      - const: ti,hdc3020
+
+  interrupts:
+    maxItems: 1
+
+  vdd-supply: true
+
+  reg:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - vdd-supply
+
+additionalProperties: false
+
+examples:
+  - |
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        humidity-sensor@47 {
+            compatible = "ti,hdc3021", "ti,hdc3020";
+            reg = <0x47>;
+            vdd-supply = <&vcc_3v3>;
+        };
+    };