regulator: dt-bindings: qcom,usb-vbus-regulator: add qcom,pm4125-vbus-reg

The pm4125 PMIC uses a different USB VBUS register layout than pm8150b.
It uses a 2-bit VBOOST voltage selector supporting output voltages of
4.25 V, 4.5 V, 4.75 V and 5.0 V, instead of a current-limit selector.

Move qcom,pm4125-vbus-reg from the pm8150b fallback items list into the
standalone enum since the driver handles it with its own match-data and
register layout.

Make regulator-min/max-microamp conditional so they are only required
for current-limit variants (pm8150b, pm6150, pm7250b, pmi632). Add an
if/then condition for qcom,pm4125-vbus-reg requiring regulator-min/
max-microvolt instead, and update the pm4125 example accordingly.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Signed-off-by: Rakesh Kota <rakesh.kota@oss.qualcomm.com>
Link: https://patch.msgid.link/20260706-add_pm4125-vbus-reg-v3-1-999d78a87b81@oss.qualcomm.com
Signed-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/regulator/qcom,usb-vbus-regulator.yaml

@@ -14,17 +14,21 @@ description: |
   regulator will be enabled in situations where the device is required to
   provide power to the connected peripheral.
 
-allOf:
-  - $ref: regulator.yaml#
+  The pm8150b variant uses an OTG current-limit selector, supporting limits
+  of 500 mA, 1000 mA, 1500 mA, 2000 mA, 2500 mA and 3000 mA.
+
+  The pm4125 variant uses a different register layout with a 2-bit VBOOST
+  voltage selector supporting output voltages of 4.25 V, 4.5 V, 4.75 V
+  and 5.0 V.
 
 properties:
   compatible:
     oneOf:
       - enum:
           - qcom,pm8150b-vbus-reg
+          - qcom,pm4125-vbus-reg
       - items:
           - enum:
-              - qcom,pm4125-vbus-reg
               - qcom,pm6150-vbus-reg
               - qcom,pm7250b-vbus-reg
               - qcom,pmi632-vbus-reg
@@ -34,11 +38,35 @@ properties:
     maxItems: 1
     description: VBUS output base address
 
+allOf:
+  - $ref: regulator.yaml#
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - qcom,pm8150b-vbus-reg
+              - qcom,pm6150-vbus-reg
+              - qcom,pm7250b-vbus-reg
+              - qcom,pmi632-vbus-reg
+    then:
+      required:
+        - regulator-min-microamp
+        - regulator-max-microamp
+
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: qcom,pm4125-vbus-reg
+    then:
+      required:
+        - regulator-min-microvolt
+        - regulator-max-microvolt
+
 required:
   - compatible
   - reg
-  - regulator-min-microamp
-  - regulator-max-microamp
 
 unevaluatedProperties: false
 
@@ -55,4 +83,16 @@ examples:
             regulator-max-microamp = <3000000>;
         };
      };
+  - |
+     pmic {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        usb-vbus-regulator@1100 {
+            compatible = "qcom,pm4125-vbus-reg";
+            reg = <0x1100>;
+            regulator-min-microvolt = <4250000>;
+            regulator-max-microvolt = <5000000>;
+        };
+     };
 ...