[PATCH net-next v2 4/5] dt-bindings: dpll: add ref-sync-sources property

Ivan Vecera
2026-03-28T08:06:54Z

Add ref-sync-sources phandle-array property to the dpll-pin schema
allowing board designers to declare which input pins can serve as
sync sources in a Reference-Sync pair. A Ref-Sync pair consists of
a clock reference and a low-frequency sync signal where the DPLL locks
to the clock but phase-aligns to the sync reference.

Update both examples in the Microchip ZL3073x binding to demonstrate
the new property with a 1 PPS sync source paired to a clock source.

Reviewed-by: Petr Oros <poros@redhat.com>
Reviewed-by: Prathosh Satish <Prathosh.Satish@microchip.com>
Signed-off-by: Ivan Vecera <ivecera@redhat.com>
---
.../devicetree/bindings/dpll/dpll-pin.yaml | 11 +++++++
.../bindings/dpll/microchip,zl30731.yaml | 30 ++++++++++++++-----
2 files changed, 34 insertions(+), 7 deletions(-)

diff --git a/Documentation/devicetree/bindings/dpll/dpll-pin.yaml b/Documentation/devicetree/bindings/dpll/dpll-pin.yaml
index 51db93b77306f..7084f102e274c 100644
--- a/Documentation/devicetree/bindings/dpll/dpll-pin.yaml
+++ b/Documentation/devicetree/bindings/dpll/dpll-pin.yaml
@@ -36,6 +36,17 @@ properties:
description: String exposed as the pin board label
$ref: /schemas/types.yaml#/definitions/string

+ ref-sync-sources:
+ description: |
+ List of phandles to input pins that can serve as the sync source
+ in a Reference-Sync pair with this pin acting as the clock source.
+ A Ref-Sync pair consists of a clock reference and a low-frequency
+ sync signal. The DPLL locks to the clock reference but
+ phase-aligns to the sync reference.
+ Only valid for input pins. Each referenced pin must be a
+ different input pin on the same device.
+ $ref: /schemas/types.yaml#/definitions/phandle-array
+
supported-frequencies-hz:
description: List of supported frequencies for this pin, expressed in Hz.

diff --git a/Documentation/devicetree/bindings/dpll/microchip,zl30731.yaml b/Documentation/devicetree/bindings/dpll/microchip,zl30731.yaml
index 17747f754b845..fa5a8f8e390cd 100644
--- a/Documentation/devicetree/bindings/dpll/microchip,zl30731.yaml
+++ b/Documentation/devicetree/bindings/dpll/microchip,zl30731.yaml
@@ -52,11 +52,19 @@ examples:
#address-cells = <1>;
#size-cells = <0>;

- pin@0 { /* REF0P */
+ sync0: pin@0 { /* REF0P - 1 PPS sync source */
reg = <0>;
connection-type = "ext";
- label = "Input 0";
- supported-frequencies-hz = /bits/ 64 <1 1000>;
+ label = "SMA1";
+ supported-frequencies-hz = /bits/ 64 <1>;
+ };
+
+ pin@1 { /* REF0N - clock source, can pair with sync0 */
+ reg = <1>;
+ connection-type = "ext";
+ label = "SMA2";
+ supported-frequencies-hz = /bits/ 64 <10000 10000000>;
+ ref-sync-sources = <&sync0>;
};
};

@@ -90,11 +98,19 @@ examples:
#address-cells = <1>;
#size-cells = <0>;

- pin@0 { /* REF0P */
+ sync1: pin@0 { /* REF0P - 1 PPS sync source */
reg = <0>;
- connection-type = "ext";
- label = "Input 0";
- supported-frequencies-hz = /bits/ 64 <1 1000>;
+ connection-type = "gnss";
+ label = "GNSS_1PPS_IN";
+ supported-frequencies-hz = /bits/ 64 <1>;
+ };
+
+ pin@1 { /* REF0N - clock source */
+ reg = <1>;
+ connection-type = "gnss";
+ label = "GNSS_10M_IN";
+ supported-frequencies-hz = /bits/ 64 <10000000>;
+ ref-sync-sources = <&sync1>;
};
};

--
2.52.0