net: stmmac: sun8i: remove of_get_phy_mode()

devm_stmmac_probe_config_dt() already gets the PHY mode from firmware,
which is stored in plat_dat->phy_interface. Therefore, we don't need to
get it in platform code.

sun8i was using of_get_phy_mode() to set plat_dat->mac_interface, which
defaults to plat_dat->phy_interface when the mac-mode DT property is
not present. As nothing in arch/*/boot/dts sets the mac-mode property,
it is highly likely that these two will be identical, and thus there
is no need for this glue driver to set plat_dat->mac_interface.

Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Michal Kubiak <michal.kubiak@intel.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://patch.msgid.link/E1tsIGs-005v09-CD@rmk-PC.armlinux.org.uk
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

drivers/net/ethernet/stmicro/stmmac/dwmac-sun8i.c

@@ -1155,11 +1155,10 @@ static int sun8i_dwmac_probe(struct platform_device *pdev)
 	struct stmmac_resources stmmac_res;
 	struct sunxi_priv_data *gmac;
 	struct device *dev = &pdev->dev;
-	phy_interface_t interface;
-	int ret;
 	struct stmmac_priv *priv;
 	struct net_device *ndev;
 	struct regmap *regmap;
+	int ret;
 
 	ret = stmmac_get_platform_resources(pdev, &stmmac_res);
 	if (ret)
@@ -1219,18 +1218,13 @@ static int sun8i_dwmac_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	ret = of_get_phy_mode(dev->of_node, &interface);
-	if (ret)
-		return -EINVAL;
-
 	plat_dat = devm_stmmac_probe_config_dt(pdev, stmmac_res.mac);
 	if (IS_ERR(plat_dat))
 		return PTR_ERR(plat_dat);
 
 	/* platform data specifying hardware features and callbacks.
 	 * hardware features were copied from Allwinner drivers.
 	 */
-	plat_dat->mac_interface = interface;
 	plat_dat->rx_coe = STMMAC_RX_COE_TYPE2;
 	plat_dat->tx_coe = 1;
 	plat_dat->flags |= STMMAC_FLAG_HAS_SUN8I;