diff --git a/Documentation/devicetree/bindings/usb/cdns,usb3.yaml b/Documentation/devicetree/bindings/usb/cdns,usb3.yaml
index e8082c5c05a2..c14a88aad31e 100644
--- a/Documentation/devicetree/bindings/usb/cdns,usb3.yaml
+++ b/Documentation/devicetree/bindings/usb/cdns,usb3.yaml
@@ -50,6 +50,9 @@ properties:
       - const: otg
       - const: wakeup
 
+  iommus:
+    maxItems: 1
+
   port:
     $ref: /schemas/graph.yaml#/properties/port
     description: