1 files changed, 54 insertions, 37 deletions

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
index 1ffde555da47..70eadc83ca68 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
@@ -296,62 +296,80 @@ out:
 }
 
 /**
- * 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	|
- *	-------------------------------
+ * stmmac_of_get_mdio() - Gets the MDIO bus from the devicetree.
+ * @np: devicetree node
  *
- * It returns 0 in case of success otherwise -ENODEV.
+ * The MDIO bus will be searched for in the following ways:
+ * 1. The compatible is "snps,dwc-qos-ethernet-4.10" && a "mdio" named
+ *    child node exists
+ * 2. A child node with the "snps,dwmac-mdio" compatible is present
+ *
+ * Return: The MDIO node if present otherwise NULL
  */
-static int stmmac_dt_phy(struct plat_stmmacenet_data *plat,
-			 struct device_node *np, struct device *dev)
+static struct device_node *stmmac_of_get_mdio(struct device_node *np)
 {
-	bool mdio = !of_phy_is_fixed_link(np);
 	static const struct of_device_id need_mdio_ids[] = {
 		{ .compatible = "snps,dwc-qos-ethernet-4.10" },
 		{},
 	};
+	struct device_node *mdio_node = NULL;
 
 	if (of_match_node(need_mdio_ids, np)) {
-		plat->mdio_node = of_get_child_by_name(np, "mdio");
+		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,
+		for_each_child_of_node(np, mdio_node) {
+			if (of_device_is_compatible(mdio_node,
 						    "snps,dwmac-mdio"))
 				break;
 		}
 	}
 
-	if (plat->mdio_node) {
+	return mdio_node;
+}
+
+/**
+ * stmmac_mdio_setup() - Populate platform related MDIO structures.
+ * @plat: driver data platform structure
+ * @np: devicetree node
+ * @dev: device pointer
+ *
+ * This searches for MDIO information from the devicetree.
+ * If an MDIO node is found, it's assigned to plat->mdio_node and
+ * plat->mdio_bus_data is allocated.
+ * If no connection can be determined, just plat->mdio_bus_data is allocated
+ * to indicate a bus should be created and scanned for a phy.
+ * If it's determined there's no MDIO bus needed, both are left NULL.
+ *
+ * This expects that plat->phy_node has already been searched for.
+ *
+ * Return: 0 on success, errno otherwise.
+ */
+static int stmmac_mdio_setup(struct plat_stmmacenet_data *plat,
+			     struct device_node *np, struct device *dev)
+{
+	bool legacy_mdio;
+
+	plat->mdio_node = stmmac_of_get_mdio(np);
+	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);
+	/* Legacy devicetrees allowed for no MDIO bus description and expect
+	 * the bus to be scanned for devices. If there's no phy or fixed-link
+	 * described assume this is the case since there must be something
+	 * connected to the MAC.
+	 */
+	legacy_mdio = !of_phy_is_fixed_link(np) && !plat->phy_node;
+	if (legacy_mdio)
+		dev_info(dev, "Deprecated MDIO bus assumption used\n");
+
+	if (plat->mdio_node || legacy_mdio) {
+		plat->mdio_bus_data = devm_kzalloc(dev,
+						   sizeof(*plat->mdio_bus_data),
+						   GFP_KERNEL);
 		if (!plat->mdio_bus_data)
 			return -ENOMEM;
 
@@ -471,8 +489,7 @@ stmmac_probe_config_dt(struct platform_device *pdev, u8 *mac)
 	if (of_property_read_u32(np, "snps,phy-addr", &plat->phy_addr) == 0)
 		dev_warn(&pdev->dev, "snps,phy-addr property is deprecated\n");
 
-	/* To Configure PHY by using all device-tree supported properties */
-	rc = stmmac_dt_phy(plat, np, &pdev->dev);
+	rc = stmmac_mdio_setup(plat, np, &pdev->dev);
 	if (rc)
 		return ERR_PTR(rc);