1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Allwinner EMAC MDIO interface driver
  4 *
  5 * Copyright 2012-2013 Stefan Roese <sr@denx.de>
  6 * Copyright 2013 Maxime Ripard <maxime.ripard@free-electrons.com>
  7 *
  8 * Based on the Linux driver provided by Allwinner:
  9 * Copyright (C) 1997  Sten Wang
 10 */
 11
 12#include <linux/delay.h>
 13#include <linux/kernel.h>
 14#include <linux/module.h>
 15#include <linux/mutex.h>
 16#include <linux/of_address.h>
 17#include <linux/of_mdio.h>
 18#include <linux/phy.h>
 19#include <linux/platform_device.h>
 20#include <linux/regulator/consumer.h>
 21
 22#define EMAC_MAC_MCMD_REG	(0x00)
 23#define EMAC_MAC_MADR_REG	(0x04)
 24#define EMAC_MAC_MWTD_REG	(0x08)
 25#define EMAC_MAC_MRDD_REG	(0x0c)
 26#define EMAC_MAC_MIND_REG	(0x10)
 27#define EMAC_MAC_SSRR_REG	(0x14)
 28
 29#define MDIO_TIMEOUT		(msecs_to_jiffies(100))
 30
 31struct sun4i_mdio_data {
 32	void __iomem		*membase;
 33	struct regulator	*regulator;
 34};
 35
 36static int sun4i_mdio_read(struct mii_bus *bus, int mii_id, int regnum)
 37{
 38	struct sun4i_mdio_data *data = bus->priv;
 39	unsigned long timeout_jiffies;
 40	int value;
 41
 42	/* issue the phy address and reg */
 43	writel((mii_id << 8) | regnum, data->membase + EMAC_MAC_MADR_REG);
 44	/* pull up the phy io line */
 45	writel(0x1, data->membase + EMAC_MAC_MCMD_REG);
 46
 47	/* Wait read complete */
 48	timeout_jiffies = jiffies + MDIO_TIMEOUT;
 49	while (readl(data->membase + EMAC_MAC_MIND_REG) & 0x1) {
 50		if (time_is_before_jiffies(timeout_jiffies))
 51			return -ETIMEDOUT;
 52		msleep(1);
 53	}
 54
 55	/* push down the phy io line */
 56	writel(0x0, data->membase + EMAC_MAC_MCMD_REG);
 57	/* and read data */
 58	value = readl(data->membase + EMAC_MAC_MRDD_REG);
 59
 60	return value;
 61}
 62
 63static int sun4i_mdio_write(struct mii_bus *bus, int mii_id, int regnum,
 64			    u16 value)
 65{
 66	struct sun4i_mdio_data *data = bus->priv;
 67	unsigned long timeout_jiffies;
 68
 69	/* issue the phy address and reg */
 70	writel((mii_id << 8) | regnum, data->membase + EMAC_MAC_MADR_REG);
 71	/* pull up the phy io line */
 72	writel(0x1, data->membase + EMAC_MAC_MCMD_REG);
 73
 74	/* Wait read complete */
 75	timeout_jiffies = jiffies + MDIO_TIMEOUT;
 76	while (readl(data->membase + EMAC_MAC_MIND_REG) & 0x1) {
 77		if (time_is_before_jiffies(timeout_jiffies))
 78			return -ETIMEDOUT;
 79		msleep(1);
 80	}
 81
 82	/* push down the phy io line */
 83	writel(0x0, data->membase + EMAC_MAC_MCMD_REG);
 84	/* and write data */
 85	writel(value, data->membase + EMAC_MAC_MWTD_REG);
 86
 87	return 0;
 88}
 89
 90static int sun4i_mdio_probe(struct platform_device *pdev)
 91{
 92	struct device_node *np = pdev->dev.of_node;
 93	struct mii_bus *bus;
 94	struct sun4i_mdio_data *data;
 95	int ret;
 96
 97	bus = mdiobus_alloc_size(sizeof(*data));
 98	if (!bus)
 99		return -ENOMEM;
100
101	bus->name = "sun4i_mii_bus";
102	bus->read = &sun4i_mdio_read;
103	bus->write = &sun4i_mdio_write;
104	snprintf(bus->id, MII_BUS_ID_SIZE, "%s-mii", dev_name(&pdev->dev));
105	bus->parent = &pdev->dev;
106
107	data = bus->priv;
108	data->membase = devm_platform_ioremap_resource(pdev, 0);
109	if (IS_ERR(data->membase)) {
110		ret = PTR_ERR(data->membase);
111		goto err_out_free_mdiobus;
112	}
113
114	data->regulator = devm_regulator_get(&pdev->dev, "phy");
115	if (IS_ERR(data->regulator)) {
116		if (PTR_ERR(data->regulator) == -EPROBE_DEFER) {
117			ret = -EPROBE_DEFER;
118			goto err_out_free_mdiobus;
119		}
120
121		dev_info(&pdev->dev, "no regulator found\n");
122		data->regulator = NULL;
123	} else {
124		ret = regulator_enable(data->regulator);
125		if (ret)
126			goto err_out_free_mdiobus;
127	}
128
129	ret = of_mdiobus_register(bus, np);
130	if (ret < 0)
131		goto err_out_disable_regulator;
132
133	platform_set_drvdata(pdev, bus);
134
135	return 0;
136
137err_out_disable_regulator:
138	if (data->regulator)
139		regulator_disable(data->regulator);
140err_out_free_mdiobus:
141	mdiobus_free(bus);
142	return ret;
143}
144
145static int sun4i_mdio_remove(struct platform_device *pdev)
146{
147	struct mii_bus *bus = platform_get_drvdata(pdev);
148	struct sun4i_mdio_data *data = bus->priv;
149
150	mdiobus_unregister(bus);
151	if (data->regulator)
152		regulator_disable(data->regulator);
153	mdiobus_free(bus);
154
155	return 0;
156}
157
158static const struct of_device_id sun4i_mdio_dt_ids[] = {
159	{ .compatible = "allwinner,sun4i-a10-mdio" },
160
161	/* Deprecated */
162	{ .compatible = "allwinner,sun4i-mdio" },
163	{ }
164};
165MODULE_DEVICE_TABLE(of, sun4i_mdio_dt_ids);
166
167static struct platform_driver sun4i_mdio_driver = {
168	.probe = sun4i_mdio_probe,
169	.remove = sun4i_mdio_remove,
170	.driver = {
171		.name = "sun4i-mdio",
172		.of_match_table = sun4i_mdio_dt_ids,
173	},
174};
175
176module_platform_driver(sun4i_mdio_driver);
177
178MODULE_DESCRIPTION("Allwinner EMAC MDIO interface driver");
179MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
180MODULE_LICENSE("GPL v2");