dt-bindings: iio: add vref support to sd modulator

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@foss.st.com>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://patch.msgid.link/20240730084640.1307938-7-olivier.moysan@foss.st.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/Documentation/devicetree/bindings/iio/adc/sigma-delta-modulator.yaml b/Documentation/devicetree/bindings/iio/adc/sigma-delta-modulator.yaml
index 7d33c4e09905c4d9c695d891ecede831aca1abda..c3a116427dc3be79cfca3d2b93c4eaef7d0f0425 100644 (file)
--- 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>;
     };