dt-bindings: hwmon: add adi,adt7470

The Analog Devices ADT7470 is a multichannel temperature sensor and
PWM fan controller. It supports monitoring up to 10 external
temperature sensors and controlling up to 4 fans.

Add the device tree binding documentation for it. This includes
support for the thermal framework by defining the "#thermal-sensor-cells"
property, and models the fan control lines as PWM channels by
defining the "#pwm-cells" property.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>
Link: https://lore.kernel.org/r/20260805-adt7470_thermalzone-v6-1-5605a5f95467@gmail.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Documentation/devicetree/bindings/hwmon/adi,adt7470.yaml

@@ -0,0 +1,58 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/hwmon/adi,adt7470.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Analog Devices ADT7470 hwmon sensor
+
+maintainers:
+  - Luiz Angelo Daros de Luca <luizluca@gmail.com>
+
+description:
+  Multi-channel temperature monitor and PWM fan controller.
+  It supports monitoring up to 10 external temperature sensors and
+  controlling up to 4 fans. The fan control lines are modeled
+  as standard PWM channels.
+
+properties:
+  compatible:
+    const: adi,adt7470
+
+  reg:
+    maxItems: 1
+
+  "#pwm-cells":
+    const: 3
+
+  "#thermal-sensor-cells":
+    const: 1
+    description:
+      Valid index values are 0 to 9, corresponding to temp1 through temp10.
+
+required:
+  - compatible
+  - reg
+
+allOf:
+  - if:
+      required:
+        - "#thermal-sensor-cells"
+    then:
+      $ref: /schemas/thermal/thermal-sensor.yaml#
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        hwmon@2f {
+            compatible = "adi,adt7470";
+            reg = <0x2f>;
+            #pwm-cells = <3>;
+            #thermal-sensor-cells = <1>;
+        };
+    };