1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) 2004-2013 Synopsys, Inc. (www.synopsys.com)
5 * MDIO implementation for ARC EMAC
8 #include <linux/delay.h>
9 #include <linux/of_mdio.h>
10 #include <linux/platform_device.h>
11 #include <linux/gpio/consumer.h>
15 /* Number of seconds we wait for "MDIO complete" flag to appear */
16 #define ARC_MDIO_COMPLETE_POLL_COUNT 1
19 * arc_mdio_complete_wait - Waits until MDIO transaction is completed.
20 * @priv: Pointer to ARC EMAC private data structure.
22 * returns: 0 on success, -ETIMEDOUT on a timeout.
24 static int arc_mdio_complete_wait(struct arc_emac_priv *priv)
28 for (i = 0; i < ARC_MDIO_COMPLETE_POLL_COUNT * 40; i++) {
29 unsigned int status = arc_reg_get(priv, R_STATUS);
34 /* Reset "MDIO complete" flag */
35 arc_reg_set(priv, R_STATUS, status);
46 * arc_mdio_read - MDIO interface read function.
47 * @bus: Pointer to MII bus structure.
48 * @phy_addr: Address of the PHY device.
49 * @reg_num: PHY register to read.
51 * returns: The register contents on success, -ETIMEDOUT on a timeout.
53 * Reads the contents of the requested register from the requested PHY
56 static int arc_mdio_read(struct mii_bus *bus, int phy_addr, int reg_num)
58 struct arc_emac_priv *priv = bus->priv;
62 arc_reg_set(priv, R_MDIO,
63 0x60020000 | (phy_addr << 23) | (reg_num << 18));
65 error = arc_mdio_complete_wait(priv);
69 value = arc_reg_get(priv, R_MDIO) & 0xffff;
71 dev_dbg(priv->dev, "arc_mdio_read(phy_addr=%i, reg_num=%x) = %x\n",
72 phy_addr, reg_num, value);
78 * arc_mdio_write - MDIO interface write function.
79 * @bus: Pointer to MII bus structure.
80 * @phy_addr: Address of the PHY device.
81 * @reg_num: PHY register to write to.
82 * @value: Value to be written into the register.
84 * returns: 0 on success, -ETIMEDOUT on a timeout.
86 * Writes the value to the requested register.
88 static int arc_mdio_write(struct mii_bus *bus, int phy_addr,
89 int reg_num, u16 value)
91 struct arc_emac_priv *priv = bus->priv;
94 "arc_mdio_write(phy_addr=%i, reg_num=%x, value=%x)\n",
95 phy_addr, reg_num, value);
97 arc_reg_set(priv, R_MDIO,
98 0x50020000 | (phy_addr << 23) | (reg_num << 18) | value);
100 return arc_mdio_complete_wait(priv);
105 * @bus: points to the mii_bus structure
106 * Description: reset the MII bus
108 static int arc_mdio_reset(struct mii_bus *bus)
110 struct arc_emac_priv *priv = bus->priv;
111 struct arc_emac_mdio_bus_data *data = &priv->bus_data;
113 if (data->reset_gpio) {
114 gpiod_set_value_cansleep(data->reset_gpio, 1);
116 gpiod_set_value_cansleep(data->reset_gpio, 0);
123 * arc_mdio_probe - MDIO probe function.
124 * @priv: Pointer to ARC EMAC private data structure.
126 * returns: 0 on success, -ENOMEM when mdiobus_alloc
127 * (to allocate memory for MII bus structure) fails.
129 * Sets up and registers the MDIO interface.
131 int arc_mdio_probe(struct arc_emac_priv *priv)
133 struct arc_emac_mdio_bus_data *data = &priv->bus_data;
134 struct device_node *np = priv->dev->of_node;
138 bus = mdiobus_alloc();
144 bus->parent = priv->dev;
145 bus->name = "Synopsys MII Bus";
146 bus->read = &arc_mdio_read;
147 bus->write = &arc_mdio_write;
148 bus->reset = &arc_mdio_reset;
150 /* optional reset-related properties */
151 data->reset_gpio = devm_gpiod_get_optional(priv->dev, "phy-reset",
153 if (IS_ERR(data->reset_gpio)) {
154 error = PTR_ERR(data->reset_gpio);
155 dev_err(priv->dev, "Failed to request gpio: %d\n", error);
160 of_property_read_u32(np, "phy-reset-duration", &data->msec);
161 /* A sane reset duration should not be longer than 1s */
162 if (data->msec > 1000)
165 snprintf(bus->id, MII_BUS_ID_SIZE, "%s", bus->name);
167 error = of_mdiobus_register(bus, priv->dev->of_node);
169 dev_err(priv->dev, "cannot register MDIO bus %s\n", bus->name);
178 * arc_mdio_remove - MDIO remove function.
179 * @priv: Pointer to ARC EMAC private data structure.
181 * Unregisters the MDIO and frees any associate memory for MII bus.
183 int arc_mdio_remove(struct arc_emac_priv *priv)
185 mdiobus_unregister(priv->bus);
186 mdiobus_free(priv->bus);