dt-bindings: iio: adc: Require generic `channel` name for channel nodes

As discussed in [1] it is more convenient to use a generic `channel`
node name for ADC channels while storing a friendly - board-specific
instead of PMIC-specific - name in the label, if/when desired to
overwrite the channel description already contained (but previously
unused) in the driver [2].

The same `channel` node name pattern has also been set in
iio/adc/adc.yaml, but this generic binding is not inherited as base for
qcom,spmi-vadc bindings due to not having any other generic elements in
common, besides the node name rule and reg property.

Replace the .* name pattern with the `channel` literal, but leave the
label property optional for bindings to choose to fall back a channel
label hardcoded in the driver [2] instead.

[1]: https://lore.kernel.org/linux-arm-msm/20221106193018.270106-1-marijn.suijten@somainline.org/T/#u
[2]: https://lore.kernel.org/linux-arm-msm/20230116220909.196926-4-marijn.suijten@somainline.org/Signed-off-by: Marijn Suijten <marijn.suijten@somainline.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20230410202917.247666-6-marijn.suijten@somainline.orgSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/devicetree/bindings/iio/adc/qcom,spmi-vadc.yaml

@@ -54,7 +54,7 @@ required:
   - '#io-channel-cells'
 
 patternProperties:
-  "^.*@[0-9a-f]+$":
+  "^channel@[0-9a-f]+$":
     type: object
     additionalProperties: false
     description: |
@@ -148,7 +148,7 @@ allOf:
 
     then:
       patternProperties:
-        "^.*@[0-9a-f]+$":
+        "^channel@[0-9a-f]+$":
           properties:
             qcom,decimation:
               enum: [ 512, 1024, 2048, 4096 ]
@@ -171,7 +171,7 @@ allOf:
 
     then:
       patternProperties:
-        "^.*@[0-9a-f]+$":
+        "^channel@[0-9a-f]+$":
           properties:
             qcom,decimation:
               enum: [ 256, 512, 1024 ]
@@ -194,7 +194,7 @@ allOf:
 
     then:
       patternProperties:
-        "^.*@[0-9a-f]+$":
+        "^channel@[0-9a-f]+$":
           properties:
             qcom,decimation:
               enum: [ 250, 420, 840 ]
@@ -217,7 +217,7 @@ allOf:
 
     then:
       patternProperties:
-        "^.*@[0-9a-f]+$":
+        "^channel@[0-9a-f]+$":
           properties:
             qcom,decimation:
               enum: [ 85, 340, 1360 ]
@@ -249,7 +249,7 @@ examples:
             #io-channel-cells = <1>;
 
             /* Channel node */
-            adc-chan@39 {
+            channel@39 {
                 reg = <0x39>;
                 qcom,decimation = <512>;
                 qcom,ratiometric;
@@ -258,19 +258,19 @@ examples:
                 qcom,pre-scaling = <1 3>;
             };
 
-            adc-chan@9 {
+            channel@9 {
                 reg = <0x9>;
             };
 
-            adc-chan@a {
+            channel@a {
                 reg = <0xa>;
             };
 
-            adc-chan@e {
+            channel@e {
                 reg = <0xe>;
             };
 
-            adc-chan@f {
+            channel@f {
                 reg = <0xf>;
             };
         };
@@ -292,16 +292,18 @@ examples:
             #io-channel-cells = <1>;
 
             /* Other properties are omitted */
-            xo-therm@44 {
+            channel@44 {
                 reg = <PMK8350_ADC7_AMUX_THM1_100K_PU>;
                 qcom,ratiometric;
                 qcom,hw-settle-time = <200>;
+                label = "xo_therm";
             };
 
-            conn-therm@47 {
+            channel@47 {
                 reg = <PM8350_ADC7_AMUX_THM4_100K_PU(1)>;
                 qcom,ratiometric;
                 qcom,hw-settle-time = <200>;
+                label = "conn_therm";
             };
         };
     };