diff --git a/drivers/of/unittest.c b/drivers/of/unittest.c
index 3832a5de4602f0a95895ebcb956a913a2068281d..e6b175370f2eb9f80393cf10f1c4647fa9615563 100644
--- a/drivers/of/unittest.c
+++ b/drivers/of/unittest.c
@@ -1946,7 +1946,7 @@ static int unittest_i2c_mux_probe(struct i2c_client *client,
 {
 	int i, nchans;
 	struct device *dev = &client->dev;
-	struct i2c_adapter *adap = to_i2c_adapter(dev->parent);
+	struct i2c_adapter *adap = client->adapter;
 	struct device_node *np = client->dev.of_node, *child;
 	struct i2c_mux_core *muxc;
 	u32 reg, max_reg;