dt-bindings: iio: adc: adi,ad7606: add supply properties

Add voltage supplies
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Guillaume Stols <gstols@baylibre.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/devicetree/bindings/iio/adc/adi,ad7606.yaml

@@ -35,6 +35,15 @@ properties:
 
   avcc-supply: true
 
+  vdrive-supply:
+    description:
+      Determines the voltage level at which the interface logic pins will
+      operate.
+
+  refin-supply:
+    description:
+      The voltage supply for optional external reference voltage.
+
   interrupts:
     description:
       The BUSY pin falling edge indicates that the conversion is over, and thus
@@ -106,6 +115,7 @@ required:
   - reg
   - spi-cpha
   - avcc-supply
+  - vdrive-supply
   - interrupts
   - adi,conversion-start-gpios
 
@@ -130,6 +140,7 @@ examples:
             spi-cpha;
 
             avcc-supply = <&adc_vref>;
+            vdrive-supply = <&vdd_supply>;
 
             interrupts = <25 IRQ_TYPE_EDGE_FALLING>;
             interrupt-parent = <&gpio>;