1 files changed, 53 insertions, 8 deletions

diff --git a/drivers/net/ethernet/arc/emac_mdio.c b/drivers/net/ethernet/arc/emac_mdio.c
index 26ba2423f33a..078b1a72c161 100644
--- a/drivers/net/ethernet/arc/emac_mdio.c
+++ b/drivers/net/ethernet/arc/emac_mdio.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright (C) 2004-2013 Synopsys, Inc. (www.synopsys.com)
  *
@@ -7,6 +8,7 @@
 #include <linux/delay.h>
 #include <linux/of_mdio.h>
 #include <linux/platform_device.h>
+#include <linux/gpio/consumer.h>
 
 #include "emac.h"
 
@@ -93,14 +95,32 @@ static int arc_mdio_write(struct mii_bus *bus, int phy_addr,
 		phy_addr, reg_num, value);
 
 	arc_reg_set(priv, R_MDIO,
-		     0x50020000 | (phy_addr << 23) | (reg_num << 18) | value);
+		    0x50020000 | (phy_addr << 23) | (reg_num << 18) | value);
 
 	return arc_mdio_complete_wait(priv);
 }
 
 /**
+ * arc_mdio_reset
+ * @bus: points to the mii_bus structure
+ * Description: reset the MII bus
+ */
+static int arc_mdio_reset(struct mii_bus *bus)
+{
+	struct arc_emac_priv *priv = bus->priv;
+	struct arc_emac_mdio_bus_data *data = &priv->bus_data;
+
+	if (data->reset_gpio) {
+		gpiod_set_value_cansleep(data->reset_gpio, 1);
+		msleep(data->msec);
+		gpiod_set_value_cansleep(data->reset_gpio, 0);
+	}
+
+	return 0;
+}
+
+/**
  * arc_mdio_probe - MDIO probe function.
- * @pdev:	Pointer to platform device.
  * @priv:	Pointer to ARC EMAC private data structure.
  *
  * returns:	0 on success, -ENOMEM when mdiobus_alloc
@@ -108,8 +128,12 @@ static int arc_mdio_write(struct mii_bus *bus, int phy_addr,
  *
  * Sets up and registers the MDIO interface.
  */
-int arc_mdio_probe(struct platform_device *pdev, struct arc_emac_priv *priv)
+int arc_mdio_probe(struct arc_emac_priv *priv)
 {
+	struct arc_emac_mdio_bus_data *data = &priv->bus_data;
+	struct device_node *np = priv->dev->of_node;
+	const char *name = "Synopsys MII Bus";
+	struct device_node *mdio_node;
 	struct mii_bus *bus;
 	int error;
 
@@ -120,17 +144,38 @@ int arc_mdio_probe(struct platform_device *pdev, struct arc_emac_priv *priv)
 	priv->bus = bus;
 	bus->priv = priv;
 	bus->parent = priv->dev;
-	bus->name = "Synopsys MII Bus",
+	bus->name = name;
 	bus->read = &arc_mdio_read;
 	bus->write = &arc_mdio_write;
+	bus->reset = &arc_mdio_reset;
+
+	/* optional reset-related properties */
+	data->reset_gpio = devm_gpiod_get_optional(priv->dev, "phy-reset",
+						   GPIOD_OUT_LOW);
+	if (IS_ERR(data->reset_gpio)) {
+		mdiobus_free(bus);
+		return dev_err_probe(priv->dev, PTR_ERR(data->reset_gpio),
+				     "Failed to request gpio\n");
+	}
+
+	of_property_read_u32(np, "phy-reset-duration", &data->msec);
+	/* A sane reset duration should not be longer than 1s */
+	if (data->msec > 1000)
+		data->msec = 1;
 
-	snprintf(bus->id, MII_BUS_ID_SIZE, "%s", pdev->name);
+	snprintf(bus->id, MII_BUS_ID_SIZE, "%s", bus->name);
 
-	error = of_mdiobus_register(bus, pdev->dev.of_node);
+	/* Backwards compatibility for EMAC nodes without MDIO subnode. */
+	mdio_node = of_get_child_by_name(np, "mdio");
+	if (!mdio_node)
+		mdio_node = of_node_get(np);
+
+	error = of_mdiobus_register(bus, mdio_node);
+	of_node_put(mdio_node);
 	if (error) {
-		dev_err(priv->dev, "cannot register MDIO bus %s\n", bus->name);
 		mdiobus_free(bus);
-		return error;
+		return dev_err_probe(priv->dev, error,
+				     "cannot register MDIO bus %s\n", name);
 	}
 
 	return 0;