net: davinci_emac: match the mdio device against its compatible if possible

BugLink: https://bugs.launchpad.net/bugs/1792377

[ Upstream commit ea0820bb ]

Device tree based systems without of_dev_auxdata will have the mdio
device named differently than "davinci_mdio(.0)". In this case use the
device's parent's compatible string for matching
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

drivers/net/ethernet/ti/davinci_emac.c

@@ -1517,6 +1517,10 @@ static int emac_devioctl(struct net_device *ndev, struct ifreq *ifrq, int cmd)
 
 static int match_first_device(struct device *dev, void *data)
 {
+	if (dev->parent && dev->parent->of_node)
+		return of_device_is_compatible(dev->parent->of_node,
+					       "ti,davinci_mdio");
+
 	return !strncmp(dev_name(dev), "davinci_mdio", 12);
 }