stmmac: Backport mdio/phy processing logic from mainline.

The mainline driver allows to specifiy a 'snps,dwmac-mdio' subnode in
the DT, which can then specify the phy and its properties.
This patch backports this feature.

Signed-off-by: Christoph Muellner <christoph.muellner@theobroma-systems.com>

2 files changed, 81 insertions, 18 deletions

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
index b7847feea688..e755e257ab54 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
@@ -95,6 +95,81 @@ static int dwmac1000_validate_ucast_entries(int ucast_entries)
 }
 
 /**
+ * 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;
+	static const struct of_device_id need_mdio_ids[] = {
+		{ .compatible = "snps,dwc-qos-ethernet-4.10" },
+		{},
+	};
+
+	/* 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 (of_match_node(need_mdio_ids, np)) {
+		plat->mdio_node = of_get_child_by_name(np, "mdio");
+	} else {
+		/**
+		 * 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
@@ -109,6 +184,7 @@ stmmac_probe_config_dt(struct platform_device *pdev, const char **mac)
 	struct device_node *np = pdev->dev.of_node;
 	struct plat_stmmacenet_data *plat;
 	struct stmmac_dma_cfg *dma_cfg;
+	int rc;
 
 	plat = devm_kzalloc(&pdev->dev, sizeof(*plat), GFP_KERNEL);
 	if (!plat)
@@ -128,30 +204,16 @@ 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 || 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 */
+	rc = stmmac_dt_phy(plat, np, &pdev->dev);
+	if (rc)
+		return ERR_PTR(rc);
 
 	of_property_read_u32(np, "tx-fifo-depth", &plat->tx_fifo_size);
 
diff --git a/include/linux/stmmac.h b/include/linux/stmmac.h
index cddcbcc7a66f..a9c5806ba92c 100644
--- a/include/linux/stmmac.h
+++ b/include/linux/stmmac.h
@@ -100,6 +100,7 @@ struct plat_stmmacenet_data {
 	int interface;
 	struct stmmac_mdio_bus_data *mdio_bus_data;
 	struct device_node *phy_node;
+	struct device_node *mdio_node;
 	struct stmmac_dma_cfg *dma_cfg;
 	int clk_csr;
 	int has_gmac;