1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2004-2013 Synopsys, Inc. (www.synopsys.com) 4 * 5 * MDIO implementation for ARC EMAC 6 */ 7 8 #include <linux/delay.h> 9 #include <linux/of_mdio.h> 10 #include <linux/platform_device.h> 11 #include <linux/gpio/consumer.h> 12 13 #include "emac.h" 14 15 /* Number of seconds we wait for "MDIO complete" flag to appear */ 16 #define ARC_MDIO_COMPLETE_POLL_COUNT 1 17 18 /** 19 * arc_mdio_complete_wait - Waits until MDIO transaction is completed. 20 * @priv: Pointer to ARC EMAC private data structure. 21 * 22 * returns: 0 on success, -ETIMEDOUT on a timeout. 23 */ 24 static int arc_mdio_complete_wait(struct arc_emac_priv *priv) 25 { 26 unsigned int i; 27 28 for (i = 0; i < ARC_MDIO_COMPLETE_POLL_COUNT * 40; i++) { 29 unsigned int status = arc_reg_get(priv, R_STATUS); 30 31 status &= MDIO_MASK; 32 33 if (status) { 34 /* Reset "MDIO complete" flag */ 35 arc_reg_set(priv, R_STATUS, status); 36 return 0; 37 } 38 39 msleep(25); 40 } 41 42 return -ETIMEDOUT; 43 } 44 45 /** 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. 50 * 51 * returns: The register contents on success, -ETIMEDOUT on a timeout. 52 * 53 * Reads the contents of the requested register from the requested PHY 54 * address. 55 */ 56 static int arc_mdio_read(struct mii_bus *bus, int phy_addr, int reg_num) 57 { 58 struct arc_emac_priv *priv = bus->priv; 59 unsigned int value; 60 int error; 61 62 arc_reg_set(priv, R_MDIO, 63 0x60020000 | (phy_addr << 23) | (reg_num << 18)); 64 65 error = arc_mdio_complete_wait(priv); 66 if (error < 0) 67 return error; 68 69 value = arc_reg_get(priv, R_MDIO) & 0xffff; 70 71 dev_dbg(priv->dev, "arc_mdio_read(phy_addr=%i, reg_num=%x) = %x\n", 72 phy_addr, reg_num, value); 73 74 return value; 75 } 76 77 /** 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. 83 * 84 * returns: 0 on success, -ETIMEDOUT on a timeout. 85 * 86 * Writes the value to the requested register. 87 */ 88 static int arc_mdio_write(struct mii_bus *bus, int phy_addr, 89 int reg_num, u16 value) 90 { 91 struct arc_emac_priv *priv = bus->priv; 92 93 dev_dbg(priv->dev, 94 "arc_mdio_write(phy_addr=%i, reg_num=%x, value=%x)\n", 95 phy_addr, reg_num, value); 96 97 arc_reg_set(priv, R_MDIO, 98 0x50020000 | (phy_addr << 23) | (reg_num << 18) | value); 99 100 return arc_mdio_complete_wait(priv); 101 } 102 103 /** 104 * arc_mdio_reset 105 * @bus: points to the mii_bus structure 106 * Description: reset the MII bus 107 */ 108 static int arc_mdio_reset(struct mii_bus *bus) 109 { 110 struct arc_emac_priv *priv = bus->priv; 111 struct arc_emac_mdio_bus_data *data = &priv->bus_data; 112 113 if (data->reset_gpio) { 114 gpiod_set_value_cansleep(data->reset_gpio, 1); 115 msleep(data->msec); 116 gpiod_set_value_cansleep(data->reset_gpio, 0); 117 } 118 119 return 0; 120 } 121 122 /** 123 * arc_mdio_probe - MDIO probe function. 124 * @priv: Pointer to ARC EMAC private data structure. 125 * 126 * returns: 0 on success, -ENOMEM when mdiobus_alloc 127 * (to allocate memory for MII bus structure) fails. 128 * 129 * Sets up and registers the MDIO interface. 130 */ 131 int arc_mdio_probe(struct arc_emac_priv *priv) 132 { 133 struct arc_emac_mdio_bus_data *data = &priv->bus_data; 134 struct device_node *np = priv->dev->of_node; 135 struct mii_bus *bus; 136 int error; 137 138 bus = mdiobus_alloc(); 139 if (!bus) 140 return -ENOMEM; 141 142 priv->bus = bus; 143 bus->priv = priv; 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; 149 150 /* optional reset-related properties */ 151 data->reset_gpio = devm_gpiod_get_optional(priv->dev, "phy-reset", 152 GPIOD_OUT_LOW); 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); 156 return error; 157 } 158 159 of_property_read_u32(np, "phy-reset-duration", &data->msec); 160 /* A sane reset duration should not be longer than 1s */ 161 if (data->msec > 1000) 162 data->msec = 1; 163 164 snprintf(bus->id, MII_BUS_ID_SIZE, "%s", bus->name); 165 166 error = of_mdiobus_register(bus, priv->dev->of_node); 167 if (error) { 168 dev_err(priv->dev, "cannot register MDIO bus %s\n", bus->name); 169 mdiobus_free(bus); 170 return error; 171 } 172 173 return 0; 174 } 175 176 /** 177 * arc_mdio_remove - MDIO remove function. 178 * @priv: Pointer to ARC EMAC private data structure. 179 * 180 * Unregisters the MDIO and frees any associate memory for MII bus. 181 */ 182 int arc_mdio_remove(struct arc_emac_priv *priv) 183 { 184 mdiobus_unregister(priv->bus); 185 mdiobus_free(priv->bus); 186 priv->bus = NULL; 187 188 return 0; 189 } 190