stmmac: fix MDIO settings

Initially the phy_bus_name was added to manipulate the
driver name but it was recently just used to manage the
fixed-link and then to take some decision at run-time.
So the patch uses the is_pseudo_fixed_link and removes
the phy_bus_name variable not necessary anymore.

The driver can manage the mdio registration by using phy-handle,
dwmac-mdio and own parameter e.g. snps,phy-addr.
This patch takes care about all these possible configurations
and fixes the mdio registration in case of there is a real
transceiver or a switch (that needs to be managed by using
fixed-link).

Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Reviewed-by: Andreas Färber <afaerber@suse.de>
Tested-by: Frank Schäfer <fschaefer.oss@googlemail.com>
Cc: Gabriel Fernandez <gabriel.fernandez@linaro.org>
Cc: Dinh Nguyen <dinh.linux@gmail.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Phil Reid <preid@electromag.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 66 insertions, 18 deletions

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
index 9cf181f839fd..cf37ea558ecc 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
@@ -132,6 +132,69 @@ static struct stmmac_axi *stmmac_axi_setup(struct platform_device *pdev)
 }
 
 /**
+ * stmmac_dt_phy - parse device-tree driver parameters to allocate PHY resources
+ * @plat: driver data platform structure
+ * @np: device tree node
+ * @dev: device pointer
+ * Description:
+ * The mdio bus will be allocated in case of a phy transceiver is on board;
+ * it will be NULL if the fixed-link is configured.
+ * If there is the "snps,dwmac-mdio" sub-node the mdio will be allocated
+ * in any case (for DSA, mdio must be registered even if fixed-link).
+ * The table below sums the supported configurations:
+ *      -------------------------------
+ *      snps,phy-addr   |     Y
+ *      -------------------------------
+ *      phy-handle      |     Y
+ *      -------------------------------
+ *      fixed-link      |     N
+ *      -------------------------------
+ *      snps,dwmac-mdio |
+ *        even if       |     Y
+ *      fixed-link      |
+ *      -------------------------------
+ *
+ * It returns 0 in case of success otherwise -ENODEV.
+ */
+static int stmmac_dt_phy(struct plat_stmmacenet_data *plat,
+                         struct device_node *np, struct device *dev)
+{
+        bool mdio = true;
+
+        /* If phy-handle property is passed from DT, use it as the PHY */
+        plat->phy_node = of_parse_phandle(np, "phy-handle", 0);
+        if (plat->phy_node)
+                dev_dbg(dev, "Found phy-handle subnode\n");
+
+        /* If phy-handle is not specified, check if we have a fixed-phy */
+        if (!plat->phy_node && of_phy_is_fixed_link(np)) {
+                if ((of_phy_register_fixed_link(np) < 0))
+                        return -ENODEV;
+
+                dev_dbg(dev, "Found fixed-link subnode\n");
+                plat->phy_node = of_node_get(np);
+                mdio = false;
+        }
+
+        /* If snps,dwmac-mdio is passed from DT, always register the MDIO */
+        for_each_child_of_node(np, plat->mdio_node) {
+                if (of_device_is_compatible(plat->mdio_node, "snps,dwmac-mdio"))
+                        break;
+        }
+
+        if (plat->mdio_node) {
+                dev_dbg(dev, "Found MDIO subnode\n");
+                mdio = true;
+        }
+
+        if (mdio)
+                plat->mdio_bus_data =
+                        devm_kzalloc(dev, sizeof(struct stmmac_mdio_bus_data),
+                                     GFP_KERNEL);
+        return 0;
+}
+
+/**
  * stmmac_probe_config_dt - parse device-tree driver parameters
  * @pdev: platform_device structure
  * @plat: driver data platform structure
@@ -165,30 +228,15 @@ stmmac_probe_config_dt(struct platform_device *pdev, const char **mac)
         /* Default to phy auto-detection */
         plat->phy_addr = -1;
 
-        /* If we find a phy-handle property, use it as the PHY */
-        plat->phy_node = of_parse_phandle(np, "phy-handle", 0);
-
-        /* If phy-handle is not specified, check if we have a fixed-phy */
-        if (!plat->phy_node && of_phy_is_fixed_link(np)) {
-                if ((of_phy_register_fixed_link(np) < 0))
-                        return ERR_PTR(-ENODEV);
-
-                plat->phy_node = of_node_get(np);
-        }
-
         /* "snps,phy-addr" is not a standard property. Mark it as deprecated
          * and warn of its use. Remove this when phy node support is added.
          */
         if (of_property_read_u32(np, "snps,phy-addr", &plat->phy_addr) == 0)
                 dev_warn(&pdev->dev, "snps,phy-addr property is deprecated\n");
 
-        if ((plat->phy_node && !of_phy_is_fixed_link(np)) || plat->phy_bus_name)
-                plat->mdio_bus_data = NULL;
-        else
-                plat->mdio_bus_data =
-                        devm_kzalloc(&pdev->dev,
-                                     sizeof(struct stmmac_mdio_bus_data),
-                                     GFP_KERNEL);
+        /* To Configure PHY by using all device-tree supported properties */
+        if (stmmac_dt_phy(plat, np, &pdev->dev))
+                return ERR_PTR(-ENODEV);
 
         of_property_read_u32(np, "tx-fifo-depth", &plat->tx_fifo_size);