diff --git a/drivers/net/ethernet/ni/nixge.c b/drivers/net/ethernet/ni/nixge.c
index 0b384f9..2761f3a 100644
--- a/drivers/net/ethernet/ni/nixge.c
+++ b/drivers/net/ethernet/ni/nixge.c
@@ -1347,7 +1347,7 @@ static int nixge_probe(struct platform_device *pdev)
 	}
 
 	priv->phy_mode = of_get_phy_mode(pdev->dev.of_node);
-	if (priv->phy_mode < 0) {
+	if ((int)priv->phy_mode < 0) {
 		netdev_err(ndev, "not find \"phy-mode\" property\n");
 		err = -EINVAL;
 		goto unregister_mdio;