diff --git a/Documentation/devicetree/bindings/net/altr,socfpga-stmmac.yaml b/Documentation/devicetree/bindings/net/altr,socfpga-stmmac.yaml
index c5d8dfe5b801..ec34daff2aa0 100644
--- a/Documentation/devicetree/bindings/net/altr,socfpga-stmmac.yaml
+++ b/Documentation/devicetree/bindings/net/altr,socfpga-stmmac.yaml
@@ -59,6 +59,7 @@ properties:
       - const: ptp_ref
 
   iommus:
+    minItems: 1
     maxItems: 2
 
   phy-mode: