Prepare for adding device_link.

The iommu consumer should use device_link to connect with the
smi-larb(supplier). then the smi-larb should run before the iommu
consumer. Here we delay the iommu driver until the smi driver is
ready, then all the iommu consumer always is after the smi driver.

When there is no this patch, if some consumer drivers run before
smi-larb, the supplier link_status is DL_DEV_NO_DRIVER(0) in the
device_link_add, then device_links_driver_bound will use WARN_ON
to complain that the link_status of supplier is not right.

Signed-off-by: Yong Wu <yong.wu@mediatek.com>
Tested-by: Dafna Hirschfeld <redacted> # on mt8173
---
 drivers/iommu/mtk_iommu.c    | 2 +-
 drivers/iommu/mtk_iommu_v1.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index 6f7c69688ce2..a02dde094788 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c

@@ -855,7 +855,7 @@ static int mtk_iommu_probe(struct platform_device *pdev)
 			id = i;
 
 		plarbdev = of_find_device_by_node(larbnode);
-		if (!plarbdev) {
+		if (!plarbdev || !plarbdev->dev.driver) {
 			of_node_put(larbnode);
 			return -EPROBE_DEFER;
 		}

diff --git a/drivers/iommu/mtk_iommu_v1.c b/drivers/iommu/mtk_iommu_v1.c
index 6861eeab182d..c259433f1130 100644
--- a/drivers/iommu/mtk_iommu_v1.c
+++ b/drivers/iommu/mtk_iommu_v1.c

@@ -603,7 +603,7 @@ static int mtk_iommu_probe(struct platform_device *pdev)
 		}
 
 		plarbdev = of_find_device_by_node(larbnode);
-		if (!plarbdev) {
+		if (!plarbdev || !plarbdev->dev.driver) {
 			of_node_put(larbnode);
 			return -EPROBE_DEFER;
 		}

-- 
2.18.0
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