[PATCH v6 6/9] dt-bindings: iio: add vref support to sd modulator

[Olivier Moysan]

Allow to specify the reference voltage used by the SD modulator.
When the SD modulator is defined as an IIO backend, the reference
voltage can be used to evaluate scaling information of the IIO device.
The reference voltage is not used otherwise.

Signed-off-by: Olivier Moysan <olivier.moysan@xxxxxxxxxxx>
---
 .../devicetree/bindings/iio/adc/sigma-delta-modulator.yaml | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/Documentation/devicetree/bindings/iio/adc/sigma-delta-modulator.yaml b/Documentation/devicetree/bindings/iio/adc/sigma-delta-modulator.yaml
index 7d33c4e09905..c3a116427dc3 100644
--- a/Documentation/devicetree/bindings/iio/adc/sigma-delta-modulator.yaml
+++ b/Documentation/devicetree/bindings/iio/adc/sigma-delta-modulator.yaml
@@ -24,6 +24,12 @@ properties:
   '#io-channel-cells':
     const: 0
 
+  vref-supply:
+    description: Phandle to the vref input analog reference voltage.
+
+dependencies:
+  vref-supply: [ '#io-backend-cells' ]
+
 required:
   - compatible
 
@@ -38,6 +44,7 @@ examples:
     // Backend binding example. SD modulator configured as an IIO backend device
     ads1201_0: adc {
       compatible = "sd-modulator";
+      vref-supply = <&vdd_adc>;
       #io-backend-cells = <0>;
     };
 
-- 
2.25.1