[PATCH] net: macb: Fix regression breaking non-MDIO fixed-link PHYs

[Ahmad Fatoum]

The referenced commit broke initializing macb on the EVB-KSZ9477 eval board.
There, of_mdiobus_register was called even for the fixed-link representing
the SPI-connected switch PHY, with the result that the driver attempts to
enumerate PHYs on a non-existent MDIO bus:

        libphy: MACB_mii_bus: probed
        mdio_bus f0028000.ethernet-ffffffff: fixed-link has invalid PHY address
        mdio_bus f0028000.ethernet-ffffffff: scan phy fixed-link at address 0
        [snip]
        mdio_bus f0028000.ethernet-ffffffff: scan phy fixed-link at address 31
        macb f0028000.ethernet: broken fixed-link specification

Cc: <sta...@vger.kernel.org>
Fixes: 739de9a1563a ("net: macb: Reorganize macb_mii bringup")
Signed-off-by: Ahmad Fatoum <a.fat...@pengutronix.de>
---
 drivers/net/ethernet/cadence/macb_main.c | 26 +++++++++++++++---------
 1 file changed, 16 insertions(+), 10 deletions(-)

diff --git a/drivers/net/ethernet/cadence/macb_main.c 
b/drivers/net/ethernet/cadence/macb_main.c
index a6c911bb5ce2..d202a03c42ed 100644
--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/drivers/net/ethernet/cadence/macb_main.c
@@ -481,11 +481,6 @@ static int macb_mii_probe(struct net_device *dev)
 
        if (np) {
                if (of_phy_is_fixed_link(np)) {
-                       if (of_phy_register_fixed_link(np) < 0) {
-                               dev_err(&bp->pdev->dev,
-                                       "broken fixed-link specification\n");
-                               return -ENODEV;
-                       }
                        bp->phy_node = of_node_get(np);
                } else {
                        bp->phy_node = of_parse_phandle(np, "phy-handle", 0);
@@ -568,7 +563,7 @@ static int macb_mii_init(struct macb *bp)
 {
        struct macb_platform_data *pdata;
        struct device_node *np;
-       int err;
+       int err = -ENXIO;
 
        /* Enable management port */
        macb_writel(bp, NCR, MACB_BIT(MPE));
@@ -591,10 +586,21 @@ static int macb_mii_init(struct macb *bp)
        dev_set_drvdata(&bp->dev->dev, bp->mii_bus);
 
        np = bp->pdev->dev.of_node;
-       if (pdata)
-               bp->mii_bus->phy_mask = pdata->phy_mask;
+       if (np && of_phy_is_fixed_link(np)) {
+               if (of_phy_register_fixed_link(np) < 0) {
+                       dev_err(&bp->pdev->dev,
+                                       "broken fixed-link specification\n");
+                       goto err_out_free_mdiobus;
+               }
+
+               err = mdiobus_register(bp->mii_bus);
+       } else {
+               if (pdata)
+                       bp->mii_bus->phy_mask = pdata->phy_mask;
+
+               err = of_mdiobus_register(bp->mii_bus, np);
+       }
 
-       err = of_mdiobus_register(bp->mii_bus, np);
        if (err)
                goto err_out_free_mdiobus;
 
@@ -606,9 +612,9 @@ static int macb_mii_init(struct macb *bp)
 
 err_out_unregister_bus:
        mdiobus_unregister(bp->mii_bus);
+err_out_free_mdiobus:
        if (np && of_phy_is_fixed_link(np))
                of_phy_deregister_fixed_link(np);
-err_out_free_mdiobus:
        of_node_put(bp->phy_node);
        mdiobus_free(bp->mii_bus);
 err_out:
-- 
2.18.0