dt-bindings: hwmon: Add Sensirion SHT30 series

Add a YAML devicetree binding for the Sensirion SHT3x/STS3x sensor
family and the compatible GXCAS GXHT30, with the ALERT interrupt,
nRESET GPIO and VDD supply as optional properties.

The SHT30, SHT31, SHT35 and SHT85 measure humidity and temperature
and differ only in accuracy and packaging, while the STS30, STS31,
STS32 and STS35 are temperature-only parts. Within each group the
parts share the same software interface, so model them with a
fallback to the base part of their group: "sensirion,sht30" for the
SHT parts and "sensirion,sts30" for the STS parts.

The GXCAS GXHT30 is a drop-in replacement for the SHT30 and uses it
as fallback as well.

Signed-off-by: Zaixiang Xu <zaixiang.xu.dev@gmail.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20260713074559.12196-3-zaixiang.xu.dev@gmail.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Documentation/devicetree/bindings/hwmon/sensirion,sht30.yaml

@@ -0,0 +1,71 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/hwmon/sensirion,sht30.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Sensirion SHT3x and GXCAS GXHT30 humidity and temperature sensors
+
+maintainers:
+  - Zaixiang Xu <zaixiang.xu.dev@gmail.com>
+
+properties:
+  compatible:
+    oneOf:
+      - enum:
+          - sensirion,sht30
+          - sensirion,sts30
+      - items:
+          - enum:
+              - gxcas,gxht30
+              - sensirion,sht31
+              - sensirion,sht35
+              - sensirion,sht85
+          - const: sensirion,sht30
+      - items:
+          - enum:
+              - sensirion,sts31
+              - sensirion,sts32
+              - sensirion,sts35
+          - const: sensirion,sts30
+
+  reg:
+    maxItems: 1
+
+  vdd-supply:
+    description: Regulator that provides power to the VDD pin.
+
+  reset-gpios:
+    maxItems: 1
+    description:
+      GPIO connected to the nRESET pin. Active low.
+
+  interrupts:
+    maxItems: 1
+    description:
+      Interrupt connected to the ALERT pin.
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        humidity-sensor@44 {
+            compatible = "gxcas,gxht30", "sensirion,sht30";
+            reg = <0x44>;
+            vdd-supply = <&vcc_3v3_reg>;
+            reset-gpios = <&gpio1 15 GPIO_ACTIVE_LOW>;
+            interrupt-parent = <&gpio1>;
+            interrupts = <16 IRQ_TYPE_LEVEL_HIGH>;
+        };
+    };