dt-bindings: iio: chemical: Add binding for CCS811 VOC sensor

This commit adds devicetree binding for AMS CCS811 VOC sensor.
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/devicetree/bindings/iio/chemical/ams,ccs811.yaml

+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/chemical/ams,ccs811.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: AMS CCS811 VOC Sensor
+
+maintainers:
+  - Narcisa Vasile <narcisaanamaria12@gmail.com>
+
+description: |
+  Ultra-Low Power Digital Gas Sensor for Monitoring Indoor Air Quality.
+
+properties:
+  compatible:
+    enum:
+      - ams,ccs811
+  reg:
+    maxItems: 1
+
+  reset-gpios:
+    description: GPIO connected to the nRESET line. This is an active low
+                 input to CCS811.
+    maxItems: 1
+
+  wakeup-gpios:
+    description: GPIO connected to the nWAKE line. This is an active low
+                 input to CCS811.
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    i2c {
+      #address-cells = <1>;
+      #size-cells = <0>;
+
+      voc@5b {
+        compatible = "ams,ccs811";
+        reg = <0x5b>;
+        reset-gpios = <&gpioa 11 GPIO_ACTIVE_LOW>;
+        wakeup-gpios = <&gpioa 12 GPIO_ACTIVE_LOW>;
+      };
+    };
+
+...