diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index 64977c131ee6..81b7734654b3 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -333,7 +333,7 @@ static int __find_legacy_master_phandle(struct device *dev, void *data)
 	int err;
 
 	of_for_each_phandle(it, err, dev->of_node, "mmu-masters",
-			    "#stream-id-cells", 0)
+			    "#stream-id-cells", -1)
 		if (it->node == np) {
 			*(void **)data = dev;
 			return 1;
diff --git a/drivers/iommu/mtk_iommu_v1.c b/drivers/iommu/mtk_iommu_v1.c
index abeeac488372..68d1de70de0c 100644
--- a/drivers/iommu/mtk_iommu_v1.c
+++ b/drivers/iommu/mtk_iommu_v1.c
@@ -426,7 +426,7 @@ static int mtk_iommu_add_device(struct device *dev)
 	int err;
 
 	of_for_each_phandle(&it, err, dev->of_node, "iommus",
-			"#iommu-cells", 0) {
+			"#iommu-cells", -1) {
 		int count = of_phandle_iterator_args(&it, iommu_spec.args,
 					MAX_PHANDLE_ARGS);
 		iommu_spec.np = of_node_get(it.node);