1/*
  2 * Allwinner EMAC MDIO interface driver
  3 *
  4 * Copyright 2012-2013 Stefan Roese <sr@denx.de>
  5 * Copyright 2013 Maxime Ripard <maxime.ripard@free-electrons.com>
  6 *
  7 * Based on the Linux driver provided by Allwinner:
  8 * Copyright (C) 1997  Sten Wang
  9 *
 10 * This file is licensed under the terms of the GNU General Public
 11 * License version 2. This program is licensed "as is" without any
 12 * warranty of any kind, whether express or implied.
 13 */
 14
 15#include <linux/delay.h>
 16#include <linux/kernel.h>
 17#include <linux/module.h>
 18#include <linux/mutex.h>
 19#include <linux/of_address.h>
 20#include <linux/of_mdio.h>
 21#include <linux/phy.h>
 22#include <linux/platform_device.h>
 23#include <linux/regulator/consumer.h>
 24
 25#define EMAC_MAC_MCMD_REG	(0x00)
 26#define EMAC_MAC_MADR_REG	(0x04)
 27#define EMAC_MAC_MWTD_REG	(0x08)
 28#define EMAC_MAC_MRDD_REG	(0x0c)
 29#define EMAC_MAC_MIND_REG	(0x10)
 30#define EMAC_MAC_SSRR_REG	(0x14)
 31
 32#define MDIO_TIMEOUT		(msecs_to_jiffies(100))
 33
 34struct sun4i_mdio_data {
 35	void __iomem		*membase;
 36	struct regulator	*regulator;
 37};
 38
 39static int sun4i_mdio_read(struct mii_bus *bus, int mii_id, int regnum)
 40{
 41	struct sun4i_mdio_data *data = bus->priv;
 42	unsigned long timeout_jiffies;
 43	int value;
 44
 45	/* issue the phy address and reg */
 46	writel((mii_id << 8) | regnum, data->membase + EMAC_MAC_MADR_REG);
 47	/* pull up the phy io line */
 48	writel(0x1, data->membase + EMAC_MAC_MCMD_REG);
 49
 50	/* Wait read complete */
 51	timeout_jiffies = jiffies + MDIO_TIMEOUT;
 52	while (readl(data->membase + EMAC_MAC_MIND_REG) & 0x1) {
 53		if (time_is_before_jiffies(timeout_jiffies))
 54			return -ETIMEDOUT;
 55		msleep(1);
 56	}
 57
 58	/* push down the phy io line */
 59	writel(0x0, data->membase + EMAC_MAC_MCMD_REG);
 60	/* and read data */
 61	value = readl(data->membase + EMAC_MAC_MRDD_REG);
 62
 63	return value;
 64}
 65
 66static int sun4i_mdio_write(struct mii_bus *bus, int mii_id, int regnum,
 67			    u16 value)
 68{
 69	struct sun4i_mdio_data *data = bus->priv;
 70	unsigned long timeout_jiffies;
 71
 72	/* issue the phy address and reg */
 73	writel((mii_id << 8) | regnum, data->membase + EMAC_MAC_MADR_REG);
 74	/* pull up the phy io line */
 75	writel(0x1, data->membase + EMAC_MAC_MCMD_REG);
 76
 77	/* Wait read complete */
 78	timeout_jiffies = jiffies + MDIO_TIMEOUT;
 79	while (readl(data->membase + EMAC_MAC_MIND_REG) & 0x1) {
 80		if (time_is_before_jiffies(timeout_jiffies))
 81			return -ETIMEDOUT;
 82		msleep(1);
 83	}
 84
 85	/* push down the phy io line */
 86	writel(0x0, data->membase + EMAC_MAC_MCMD_REG);
 87	/* and write data */
 88	writel(value, data->membase + EMAC_MAC_MWTD_REG);
 89
 90	return 0;
 91}
 92
 93static int sun4i_mdio_probe(struct platform_device *pdev)
 94{
 95	struct device_node *np = pdev->dev.of_node;
 96	struct mii_bus *bus;
 97	struct sun4i_mdio_data *data;
 98	struct resource *res;
 99	int ret;
100
101	bus = mdiobus_alloc_size(sizeof(*data));
102	if (!bus)
103		return -ENOMEM;
104
105	bus->name = "sun4i_mii_bus";
106	bus->read = &sun4i_mdio_read;
107	bus->write = &sun4i_mdio_write;
108	snprintf(bus->id, MII_BUS_ID_SIZE, "%s-mii", dev_name(&pdev->dev));
109	bus->parent = &pdev->dev;
110
111	data = bus->priv;
112	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
113	data->membase = devm_ioremap_resource(&pdev->dev, res);
114	if (IS_ERR(data->membase)) {
115		ret = PTR_ERR(data->membase);
116		goto err_out_free_mdiobus;
117	}
118
119	data->regulator = devm_regulator_get(&pdev->dev, "phy");
120	if (IS_ERR(data->regulator)) {
121		if (PTR_ERR(data->regulator) == -EPROBE_DEFER)
122			return -EPROBE_DEFER;
123
124		dev_info(&pdev->dev, "no regulator found\n");
125		data->regulator = NULL;
126	} else {
127		ret = regulator_enable(data->regulator);
128		if (ret)
129			goto err_out_free_mdiobus;
130	}
131
132	ret = of_mdiobus_register(bus, np);
133	if (ret < 0)
134		goto err_out_disable_regulator;
135
136	platform_set_drvdata(pdev, bus);
137
138	return 0;
139
140err_out_disable_regulator:
141	if (data->regulator)
142		regulator_disable(data->regulator);
143err_out_free_mdiobus:
144	mdiobus_free(bus);
145	return ret;
146}
147
148static int sun4i_mdio_remove(struct platform_device *pdev)
149{
150	struct mii_bus *bus = platform_get_drvdata(pdev);
151
152	mdiobus_unregister(bus);
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");