diff options
Diffstat (limited to 'drivers/net/ethernet/arc/emac_mdio.c')
| -rw-r--r-- | drivers/net/ethernet/arc/emac_mdio.c | 190 |
1 files changed, 190 insertions, 0 deletions
diff --git a/drivers/net/ethernet/arc/emac_mdio.c b/drivers/net/ethernet/arc/emac_mdio.c new file mode 100644 index 000000000..87f40c2ba --- /dev/null +++ b/drivers/net/ethernet/arc/emac_mdio.c @@ -0,0 +1,190 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2004-2013 Synopsys, Inc. (www.synopsys.com) + * + * MDIO implementation for ARC EMAC + */ + +#include <linux/delay.h> +#include <linux/of_mdio.h> +#include <linux/platform_device.h> +#include <linux/gpio/consumer.h> + +#include "emac.h" + +/* Number of seconds we wait for "MDIO complete" flag to appear */ +#define ARC_MDIO_COMPLETE_POLL_COUNT 1 + +/** + * arc_mdio_complete_wait - Waits until MDIO transaction is completed. + * @priv: Pointer to ARC EMAC private data structure. + * + * returns: 0 on success, -ETIMEDOUT on a timeout. + */ +static int arc_mdio_complete_wait(struct arc_emac_priv *priv) +{ + unsigned int i; + + for (i = 0; i < ARC_MDIO_COMPLETE_POLL_COUNT * 40; i++) { + unsigned int status = arc_reg_get(priv, R_STATUS); + + status &= MDIO_MASK; + + if (status) { + /* Reset "MDIO complete" flag */ + arc_reg_set(priv, R_STATUS, status); + return 0; + } + + msleep(25); + } + + return -ETIMEDOUT; +} + +/** + * arc_mdio_read - MDIO interface read function. + * @bus: Pointer to MII bus structure. + * @phy_addr: Address of the PHY device. + * @reg_num: PHY register to read. + * + * returns: The register contents on success, -ETIMEDOUT on a timeout. + * + * Reads the contents of the requested register from the requested PHY + * address. + */ +static int arc_mdio_read(struct mii_bus *bus, int phy_addr, int reg_num) +{ + struct arc_emac_priv *priv = bus->priv; + unsigned int value; + int error; + + arc_reg_set(priv, R_MDIO, + 0x60020000 | (phy_addr << 23) | (reg_num << 18)); + + error = arc_mdio_complete_wait(priv); + if (error < 0) + return error; + + value = arc_reg_get(priv, R_MDIO) & 0xffff; + + dev_dbg(priv->dev, "arc_mdio_read(phy_addr=%i, reg_num=%x) = %x\n", + phy_addr, reg_num, value); + + return value; +} + +/** + * arc_mdio_write - MDIO interface write function. + * @bus: Pointer to MII bus structure. + * @phy_addr: Address of the PHY device. + * @reg_num: PHY register to write to. + * @value: Value to be written into the register. + * + * returns: 0 on success, -ETIMEDOUT on a timeout. + * + * Writes the value to the requested register. + */ +static int arc_mdio_write(struct mii_bus *bus, int phy_addr, + int reg_num, u16 value) +{ + struct arc_emac_priv *priv = bus->priv; + + dev_dbg(priv->dev, + "arc_mdio_write(phy_addr=%i, reg_num=%x, value=%x)\n", + phy_addr, reg_num, value); + + arc_reg_set(priv, R_MDIO, + 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. + * @priv: Pointer to ARC EMAC private data structure. + * + * returns: 0 on success, -ENOMEM when mdiobus_alloc + * (to allocate memory for MII bus structure) fails. + * + * Sets up and registers the MDIO interface. + */ +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 mii_bus *bus; + int error; + + bus = mdiobus_alloc(); + if (!bus) + return -ENOMEM; + + priv->bus = bus; + bus->priv = priv; + bus->parent = priv->dev; + 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", bus->name); + + error = of_mdiobus_register(bus, priv->dev->of_node); + if (error) { + mdiobus_free(bus); + return dev_err_probe(priv->dev, error, + "cannot register MDIO bus %s\n", name); + } + + return 0; +} + +/** + * arc_mdio_remove - MDIO remove function. + * @priv: Pointer to ARC EMAC private data structure. + * + * Unregisters the MDIO and frees any associate memory for MII bus. + */ +int arc_mdio_remove(struct arc_emac_priv *priv) +{ + mdiobus_unregister(priv->bus); + mdiobus_free(priv->bus); + priv->bus = NULL; + + return 0; +} |