diff --git a/Documentation/devicetree/bindings/iio/adc/maxim,max1238.yaml b/Documentation/devicetree/bindings/iio/adc/maxim,max1238.yaml
index 60d7b34e3286..ae3c89393f1a 100644
--- a/Documentation/devicetree/bindings/iio/adc/maxim,max1238.yaml
+++ b/Documentation/devicetree/bindings/iio/adc/maxim,max1238.yaml
@@ -53,6 +53,9 @@ properties:
   reg:
     maxItems: 1
 
+  "#io-channel-cells":
+    const: 1
+
   vcc-supply: true
   vref-supply:
     description: Optional external reference.  If not supplied, internal