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 void 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
156static const struct of_device_id sun4i_mdio_dt_ids[] = {
157	{ .compatible = "allwinner,sun4i-a10-mdio" },
158
159	/* Deprecated */
160	{ .compatible = "allwinner,sun4i-mdio" },
161	{ }
162};
163MODULE_DEVICE_TABLE(of, sun4i_mdio_dt_ids);
164
165static struct platform_driver sun4i_mdio_driver = {
166	.probe = sun4i_mdio_probe,
167	.remove_new = sun4i_mdio_remove,
168	.driver = {
169		.name = "sun4i-mdio",
170		.of_match_table = sun4i_mdio_dt_ids,
171	},
172};
173
174module_platform_driver(sun4i_mdio_driver);
175
176MODULE_DESCRIPTION("Allwinner EMAC MDIO interface driver");
177MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
178MODULE_LICENSE("GPL v2");
179