[PATCH] net: dsa: realtek-smi: fix OF child-node lookup

[Johan Hovold]

Use the new of_get_compatible_child() helper to look up child nodes to
avoid ever matching non-child nodes elsewhere in the tree.

Also fix up the related struct device_node leaks.

Fixes: d8652956cf37 ("net: dsa: realtek-smi: Add Realtek SMI driver")
Cc: stable <sta...@vger.kernel.org>     # 4.19: 36156f9241cb0
Cc: Linus Walleij <linus.wall...@linaro.org>
Signed-off-by: Johan Hovold <jo...@kernel.org>
---

Note that this one has only been compile tested.


 drivers/net/dsa/realtek-smi.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/drivers/net/dsa/realtek-smi.c b/drivers/net/dsa/realtek-smi.c
index b4b839a1d095..ad41ec63cc9f 100644
--- a/drivers/net/dsa/realtek-smi.c
+++ b/drivers/net/dsa/realtek-smi.c
@@ -347,16 +347,17 @@ int realtek_smi_setup_mdio(struct realtek_smi *smi)
        struct device_node *mdio_np;
        int ret;
 
-       mdio_np = of_find_compatible_node(smi->dev->of_node, NULL,
-                                         "realtek,smi-mdio");
+       mdio_np = of_get_compatible_child(smi->dev->of_node, 
"realtek,smi-mdio");
        if (!mdio_np) {
                dev_err(smi->dev, "no MDIO bus node\n");
                return -ENODEV;
        }
 
        smi->slave_mii_bus = devm_mdiobus_alloc(smi->dev);
-       if (!smi->slave_mii_bus)
-               return -ENOMEM;
+       if (!smi->slave_mii_bus) {
+               ret = -ENOMEM;
+               goto err_put_node;
+       }
        smi->slave_mii_bus->priv = smi;
        smi->slave_mii_bus->name = "SMI slave MII";
        smi->slave_mii_bus->read = realtek_smi_mdio_read;
@@ -371,10 +372,15 @@ int realtek_smi_setup_mdio(struct realtek_smi *smi)
        if (ret) {
                dev_err(smi->dev, "unable to register MDIO bus %s\n",
                        smi->slave_mii_bus->id);
-               of_node_put(mdio_np);
+               goto err_put_node;
        }
 
        return 0;
+
+err_put_node:
+       of_node_put(mdio_np);
+
+       return ret;
 }
 
 static int realtek_smi_probe(struct platform_device *pdev)
@@ -457,6 +463,8 @@ static int realtek_smi_remove(struct platform_device *pdev)
        struct realtek_smi *smi = dev_get_drvdata(&pdev->dev);
 
        dsa_unregister_switch(smi->ds);
+       if (smi->slave_mii_bus)
+               of_node_put(smi->slave_mii_bus->dev.of_node);
        gpiod_set_value(smi->reset, 1);
 
        return 0;
-- 
2.20.1