lan743x: correctly handle chips with internal PHY

Commit 6f197fb63850 ("lan743x: Added fixed link and RGMII support")
assumes that chips with an internal PHY will never have a devicetree
entry. This is incorrect: even for these chips, a devicetree entry
can be useful e.g. to pass the mac address from bootloader to chip:

    &pcie {
            status = "okay";

            host@0 {
                    reg = <0 0 0 0 0>;

                    #address-cells = <3>;
                    #size-cells = <2>;

                    lan7430: ethernet@0 {
                            /* LAN7430 with internal PHY */
                            compatible = "microchip,lan743x";
                            status = "okay";
                            reg = <0 0 0 0 0>;
                            /* filled in by bootloader */
                            local-mac-address = [00 00 00 00 00 00];
                    };
            };
    };

If a devicetree entry is present, the driver will not attach the chip
to its internal phy, and the chip will be non-operational.

Fix by tweaking the phy connection algorithm:
- first try to connect to a phy specified in the devicetree
  (could be 'real' phy, or just a 'fixed-link')
- if that doesn't succeed, try to connect to an internal phy, even
  if the chip has a devnode

Tested on a LAN7430 with internal PHY. I cannot test a device using
fixed-link, as I do not have access to one.

Fixes: 6f197fb63850 ("lan743x: Added fixed link and RGMII support")
Tested-by: Sven Van Asbroeck <thesven73@gmail.com> # lan7430
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com>
Link: https://lore.kernel.org/r/20201108171224.23829-1-TheSven73@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/microchip/lan743x_main.c b/drivers/net/ethernet/microchip/lan743x_main.c
index a193884..bd77877 100644 (file)
--- a/drivers/net/ethernet/microchip/lan743x_main.c
+++ b/drivers/net/ethernet/microchip/lan743x_main.c
@@ -1026,9 +1026,9 @@ static int lan743x_phy_open(struct lan743x_adapter *adapter)
 
        netdev = adapter->netdev;
        phynode = of_node_get(adapter->pdev->dev.of_node);
-       adapter->phy_mode = PHY_INTERFACE_MODE_GMII;
 
        if (phynode) {
+               /* try devicetree phy, or fixed link */
                of_get_phy_mode(phynode, &adapter->phy_mode);
 
                if (of_phy_is_fixed_link(phynode)) {
@@ -1044,13 +1044,15 @@ static int lan743x_phy_open(struct lan743x_adapter *adapter)
                                        lan743x_phy_link_status_change, 0,
                                        adapter->phy_mode);
                of_node_put(phynode);
-               if (!phydev)
-                       goto return_error;
-       } else {
+       }
+
+       if (!phydev) {
+               /* try internal phy */
                phydev = phy_find_first(adapter->mdiobus);
                if (!phydev)
                        goto return_error;
 
+               adapter->phy_mode = PHY_INTERFACE_MODE_GMII;
                ret = phy_connect_direct(netdev, phydev,
                                         lan743x_phy_link_status_change,
                                         adapter->phy_mode);