dt-bindings: hwmon: allow specifying channels for tmp421

Add binding description for the per temperature channel configuration
like labels and n-factor.

Signed-off-by: Krzysztof Adamski <krzysztof.adamski@nokia.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/d1721a50efc0f88728614b5b07c0d9332ae4971c.1634206677.git.krzysztof.adamski@nokia.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Documentation/devicetree/bindings/hwmon/ti,tmp421.yaml

@@ -24,12 +24,50 @@ properties:
   reg:
     maxItems: 1
 
+  '#address-cells':
+    const: 1
+
+  '#size-cells':
+    const: 0
+
 required:
   - compatible
   - reg
 
 additionalProperties: false
 
+patternProperties:
+  "^channel@([0-3])$":
+    type: object
+    description: |
+      Represents channels of the device and their specific configuration.
+
+    properties:
+      reg:
+        description: |
+          The channel number. 0 is local channel, 1-3 are remote channels
+        items:
+          minimum: 0
+          maximum: 3
+
+      label:
+        description: |
+          A descriptive name for this channel, like "ambient" or "psu".
+
+      ti,n-factor:
+        description: |
+          The value (two's complement) to be programmed in the channel specific N correction register.
+          For remote channels only.
+        $ref: /schemas/types.yaml#/definitions/uint32
+        items:
+          minimum: 0
+          maximum: 255
+
+    required:
+      - reg
+
+    additionalProperties: false
+
 examples:
   - |
     i2c {
@@ -41,3 +79,32 @@ examples:
         reg = <0x4c>;
       };
     };
+  - |
+    i2c {
+      #address-cells = <1>;
+      #size-cells = <0>;
+
+      sensor@4c {
+        compatible = "ti,tmp422";
+        reg = <0x4c>;
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        channel@0 {
+          reg = <0x0>;
+          ti,n-factor = <0x1>;
+          label = "local";
+        };
+
+        channel@1 {
+          reg = <0x1>;
+          ti,n-factor = <0x0>;
+          label = "somelabel";
+        };
+
+        channel@2 {
+          reg = <0x2>;
+          status = "disabled";
+        };
+      };
+    };