regulator: dt-bindings: mt6358: Add regulator-allowed-modes property

The MT6358 PMIC allows changing operating modes for the buck regulators,
but not the LDOs. Existing device trees and the Linux implementation
already utilize this through the standard regulator-allowed-modes
property.

The values currently used in existing device trees are simply raw
numbers. The values in the Linux driver are matching numbers defined
with macros denoting the two supported modes. Turns out these two
modes are common across parts of the larger MT63xx PMIC family. The
MT6397 regulator binding already has macros for the two modes, with
matching numbers.

Codify the supported values for regulator-allowed-modes for the MT6358
in the device tree binding: 0 and 1 are supported for buck regulators,
and the property should not be present for LDO regulators. Users should
use the dt-bindings/regulator/mediatek,mt6397-regulator.h header for
the macros, instead of using raw numbers.
Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20230928085537.3246669-4-wenst@chromium.orgSigned-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/regulator/mediatek,mt6358-regulator.yaml

@@ -22,12 +22,16 @@ properties:
     description: LDOs with fixed 2.2V output and 0~100/10mV tuning
     type: object
     $ref: regulator.yaml#
+    properties:
+      regulator-allowed-modes: false
     unevaluatedProperties: false
 
   ldo_vusb:
     description: LDOs with fixed 3.0V output and 0~100/10mV tuning
     type: object
     $ref: regulator.yaml#
+    properties:
+      regulator-allowed-modes: false
     unevaluatedProperties: false
 
 
@@ -36,36 +40,55 @@ patternProperties:
     description: Buck regulators
     type: object
     $ref: regulator.yaml#
+    properties:
+      regulator-allowed-modes:
+        description: |
+          Buck regulatpr operating modes allowed. Valid values below.
+          Users should use the macros from dt-bindings/regulator/mediatek,mt6397-regulator.h
+            0 (MT6397_BUCK_MODE_AUTO): Auto PFM/PWM mode
+            1 (MT6397_BUCK_MODE_FORCE_PWM): Forced PWM mode
+        items:
+          enum: [0, 1]
     unevaluatedProperties: false
 
   "^ldo_v(a|rf)12$":
     description: LDOs with fixed 1.2V output and 0~100/10mV tuning
     type: object
     $ref: regulator.yaml#
+    properties:
+      regulator-allowed-modes: false
     unevaluatedProperties: false
 
   "^ldo_v((aux|cn|io|rf)18|camio)$":
     description: LDOs with fixed 1.8V output and 0~100/10mV tuning
     type: object
     $ref: regulator.yaml#
+    properties:
+      regulator-allowed-modes: false
     unevaluatedProperties: false
 
   "^ldo_v(aud|bif|cn|fe|io)28$":
     description: LDOs with fixed 2.8V output and 0~100/10mV tuning
     type: object
     $ref: regulator.yaml#
+    properties:
+      regulator-allowed-modes: false
     unevaluatedProperties: false
 
   "^ldo_vsram_(gpu|others|proc1[12])$":
     description: LDOs with variable output
     type: object
     $ref: regulator.yaml#
+    properties:
+      regulator-allowed-modes: false
     unevaluatedProperties: false
 
   "^ldo_v(cama[12]|camd|cn33|dram2|efuse|emc|ibr|ldo28|mc|mch|sim[12])$":
     description: LDOs with variable output and 0~100/10mV tuning
     type: object
     $ref: regulator.yaml#
+    properties:
+      regulator-allowed-modes: false
     unevaluatedProperties: false
 
 required:
@@ -75,6 +98,8 @@ additionalProperties: false
 
 examples:
   - |
+    #include <dt-bindings/regulator/mediatek,mt6397-regulator.h>
+
     regulator {
         compatible = "mediatek,mt6358-regulator";
 
@@ -84,6 +109,8 @@ examples:
             regulator-max-microvolt = <900000>;
             regulator-ramp-delay = <6250>;
             regulator-enable-ramp-delay = <200>;
+            regulator-allowed-modes = <MT6397_BUCK_MODE_AUTO
+                                       MT6397_BUCK_MODE_FORCE_PWM>;
         };
 
         ldo_vsram_gpu {