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// 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;
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 = "Synopsys MII Bus";
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)) {
error = PTR_ERR(data->reset_gpio);
dev_err(priv->dev, "Failed to request gpio: %d\n", error);
return error;
}
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) {
dev_err(priv->dev, "cannot register MDIO bus %s\n", bus->name);
mdiobus_free(bus);
return error;
}
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;
}
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