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, i;
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	bus->irq = devm_kzalloc(&pdev->dev, sizeof(int) * PHY_MAX_ADDR,
112			GFP_KERNEL);
113	if (!bus->irq) {
114		ret = -ENOMEM;
115		goto err_out_free_mdiobus;
116	}
117
118	for (i = 0; i < PHY_MAX_ADDR; i++)
119		bus->irq[i] = PHY_POLL;
120
121	data = bus->priv;
122	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
123	data->membase = devm_ioremap_resource(&pdev->dev, res);
124	if (IS_ERR(data->membase)) {
125		ret = PTR_ERR(data->membase);
126		goto err_out_free_mdiobus;
127	}
128
129	data->regulator = devm_regulator_get(&pdev->dev, "phy");
130	if (IS_ERR(data->regulator)) {
131		if (PTR_ERR(data->regulator) == -EPROBE_DEFER)
132			return -EPROBE_DEFER;
133
134		dev_info(&pdev->dev, "no regulator found\n");
135	} else {
136		ret = regulator_enable(data->regulator);
137		if (ret)
138			goto err_out_free_mdiobus;
139	}
140
141	ret = of_mdiobus_register(bus, np);
142	if (ret < 0)
143		goto err_out_disable_regulator;
144
145	platform_set_drvdata(pdev, bus);
146
147	return 0;
148
149err_out_disable_regulator:
150	regulator_disable(data->regulator);
151err_out_free_mdiobus:
152	mdiobus_free(bus);
153	return ret;
154}
155
156static int sun4i_mdio_remove(struct platform_device *pdev)
157{
158	struct mii_bus *bus = platform_get_drvdata(pdev);
159
160	mdiobus_unregister(bus);
161	mdiobus_free(bus);
162
163	return 0;
164}
165
166static const struct of_device_id sun4i_mdio_dt_ids[] = {
167	{ .compatible = "allwinner,sun4i-a10-mdio" },
168
169	/* Deprecated */
170	{ .compatible = "allwinner,sun4i-mdio" },
171	{ }
172};
173MODULE_DEVICE_TABLE(of, sun4i_mdio_dt_ids);
174
175static struct platform_driver sun4i_mdio_driver = {
176	.probe = sun4i_mdio_probe,
177	.remove = sun4i_mdio_remove,
178	.driver = {
179		.name = "sun4i-mdio",
180		.of_match_table = sun4i_mdio_dt_ids,
181	},
182};
183
184module_platform_driver(sun4i_mdio_driver);
185
186MODULE_DESCRIPTION("Allwinner EMAC MDIO interface driver");
187MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
188MODULE_LICENSE("GPL");
189