[PATCH] iommu: rockchip: fix building without CONFIG_OF

[Arnd Bergmann <arnd@arndb.de>]

We get a build error when compiling the iommu driver without CONFIG_OF:

drivers/iommu/rockchip-iommu.c: In function 'rk_iommu_of_xlate':
drivers/iommu/rockchip-iommu.c:1101:2: error: implicit declaration of function 'of_dev_put'; did you mean 'of_node_put'? [-Werror=implicit-function-declaration]

This replaces the of_dev_put() with the equivalent platform_device_put(),
and adds an error check for of_find_device_by_node() returning NULL,
which seems to be appropriate here given that we pass the device into
platform_get_drvdata() next, and that of_find_device_by_node() might
theoretically return a NULL pointer.

Fixes: 5fd577c3eac3 ("iommu/rockchip: Use OF_IOMMU to attach devices automatically")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
This warning appears to only have been introduced in linux-next after
the merge window opened.
---
 drivers/iommu/rockchip-iommu.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/rockchip-iommu.c b/drivers/iommu/rockchip-iommu.c
index 5fc8656c60f9..fe9c9cc1a9d4 100644
--- a/drivers/iommu/rockchip-iommu.c
+++ b/drivers/iommu/rockchip-iommu.c
@@ -1094,11 +1094,15 @@ static int rk_iommu_of_xlate(struct device *dev,
 		return -ENOMEM;
 
 	iommu_dev = of_find_device_by_node(args->np);
+	if (!iommu_dev) {
+		kfree(data);
+		return -ENODEV;
+	}
 
 	data->iommu = platform_get_drvdata(iommu_dev);
 	dev->archdata.iommu = data;
 
-	of_dev_put(iommu_dev);
+	platform_device_put(iommu_dev);
 
 	return 0;
 }
-- 
2.9.0