devicetree: hwmon: shtc1: add sensirion,shtc1.yaml

Add documentation for the newly added DTS support in the shtc1 driver.
To align with the drivers logic to have high precision by default
a boolean sensirion,low-precision is used to switch to low precision.
Signed-off-by: Chris Ruehl <chris.ruehl@gtsys.com.hk>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20200815012227.32538-3-chris.ruehl@gtsys.com.hkSigned-off-by: Guenter Roeck <linux@roeck-us.net>

Documentation/devicetree/bindings/hwmon/sensirion,shtc1.yaml

+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/hwmon/sensirion,shtc1.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Sensirion SHTC1 Humidity and Temperature Sensor IC
+
+maintainers:
+  - Christopher Ruehl chris.ruehl@gtsys.com.hk
+
+description: |
+  The SHTC1, SHTW1 and SHTC3 are digital humidity and temperature sensor
+  designed especially for battery-driven high-volume consumer electronics
+  applications.
+  For further information refere to Documentation/hwmon/shtc1.rst
+
+  This binding document describes the binding for the hardware monitor
+  portion of the driver.
+
+properties:
+  compatible:
+    enum:
+      - sensirion,shtc1
+      - sensirion,shtw1
+      - sensirion,shtc3
+
+  reg:
+    const: 0x70
+
+  sensirion,blocking-io:
+    $ref: /schemas/types.yaml#definitions/flag
+    description:
+      If set, the driver hold the i2c bus until measurement is finished.
+
+  sensirion,low-precision:
+    $ref: /schemas/types.yaml#definitions/flag
+    description:
+      If set, the sensor aquire data with low precision (not recommended).
+      The driver aquire data with high precision by default.
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    i2c {
+      #address-cells = <1>;
+      #size-cells = <0>;
+      clock-frequency = <400000>;
+
+      shtc3@70 {
+        compatible = "sensirion,shtc3";
+        reg = <0x70>;
+        sensirion,blocking-io;
+      };
+    };
+...