dt-bindings: hwmon: Add maxim max31790

Add device tree bindings and an example for max31790 device.

Signed-off-by: Chanh Nguyen <chanh@os.amperecomputing.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Message-ID: <20240822084808.299884-1-chanh@os.amperecomputing.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Documentation/devicetree/bindings/hwmon/maxim,max31790.yaml

@@ -0,0 +1,70 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/hwmon/maxim,max31790.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: The Maxim MAX31790 Fan Controller
+
+maintainers:
+  - Guenter Roeck <linux@roeck-us.net>
+  - Chanh Nguyen <chanh@os.amperecomputing.com>
+
+description: >
+  The MAX31790 controls the speeds of up to six fans using six
+  independent PWM outputs. The desired fan speeds (or PWM duty cycles)
+  are written through the I2C interface.
+
+  Datasheets:
+    https://datasheets.maximintegrated.com/en/ds/MAX31790.pdf
+
+properties:
+  compatible:
+    const: maxim,max31790
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  resets:
+    maxItems: 1
+
+  "#pwm-cells":
+    const: 1
+
+patternProperties:
+  "^fan-[0-9]+$":
+    $ref: fan-common.yaml#
+    unevaluatedProperties: false
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    i2c {
+      #address-cells = <1>;
+      #size-cells = <0>;
+
+      pwm_provider: fan-controller@20 {
+        compatible = "maxim,max31790";
+        reg = <0x20>;
+        clocks = <&sys_clk>;
+        resets = <&reset 0>;
+        #pwm-cells = <1>;
+
+        fan-0 {
+          pwms = <&pwm_provider 1>;
+        };
+
+        fan-1 {
+          pwms = <&pwm_provider 2>;
+        };
+      };
+    };
+