[RFC PATCH 1/5] dt-bindings: mfd: x-powers,axp152: Add polyphased property

[Andre Przywara <andre.przywara@arm.com>]

Some X-Powers AXP PMICs can combine some of their DC/DC buck converter
outputs in a multi-phase fashion, to achieve higher currents and
decrease the output ripple. The datasheets call this poly-phase. This is
programmable in the PMIC, although often set up as the PMIC's reset
default.

Add the "x-powers,polyphased" property to the binding, to describe those
pairs or tuples of regulators that should work together. In the lead
regulator node, the property lists the phandles of the connected
regulators. Just an empty property means no poly-phasing.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
---
 .../devicetree/bindings/mfd/x-powers,axp152.yaml   | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/Documentation/devicetree/bindings/mfd/x-powers,axp152.yaml b/Documentation/devicetree/bindings/mfd/x-powers,axp152.yaml
index 45f015d63df16..260c4c0afc475 100644
--- a/Documentation/devicetree/bindings/mfd/x-powers,axp152.yaml
+++ b/Documentation/devicetree/bindings/mfd/x-powers,axp152.yaml
@@ -304,6 +304,15 @@ properties:
               noise. This probably makes sense for HiFi audio related
               applications that aren't battery constrained.
 
+          x-powers,polyphased:
+            $ref: /schemas/types.yaml#/definitions/phandle-array
+            description:
+              A list of phandles pointing to other regulators that should be
+              polyphased with this regulator. The linked regulators will be
+              synchronised with this regulator, within the PMIC, but only if
+              supported by the PMIC. An empty list means this regulator
+              should be configured in a single-phase setup.
+
     additionalProperties: false
 
 required:
@@ -377,6 +386,7 @@ examples:
                     regulator-min-microvolt = <1000000>;
                     regulator-max-microvolt = <1450000>;
                     regulator-name = "vdd-cpu";
+                    x-powers,polyphased = <&reg_dcdc4>;
                 };
 
                 reg_dcdc3: dcdc3 {
@@ -386,6 +396,10 @@ examples:
                     regulator-name = "vdd-int-dll";
                 };
 
+                reg_dcdc4: dcdc4 {
+                    /* dual-phased with DCDC2 */
+                };
+
                 reg_ldo1: ldo1 {
                     /* LDO1 is a fixed output regulator */
                     regulator-always-on;
-- 
2.46.4