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 
31 struct sun4i_mdio_data {
32 	void __iomem		*membase;
33 	struct regulator	*regulator;
34 };
35 
sun4i_mdio_read(struct mii_bus * bus,int mii_id,int regnum)36 static 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 
sun4i_mdio_write(struct mii_bus * bus,int mii_id,int regnum,u16 value)63 static 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 
sun4i_mdio_probe(struct platform_device * pdev)90 static 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 
137 err_out_disable_regulator:
138 	if (data->regulator)
139 		regulator_disable(data->regulator);
140 err_out_free_mdiobus:
141 	mdiobus_free(bus);
142 	return ret;
143 }
144 
sun4i_mdio_remove(struct platform_device * pdev)145 static 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 
158 static 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 };
165 MODULE_DEVICE_TABLE(of, sun4i_mdio_dt_ids);
166 
167 static 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 
176 module_platform_driver(sun4i_mdio_driver);
177 
178 MODULE_DESCRIPTION("Allwinner EMAC MDIO interface driver");
179 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
180 MODULE_LICENSE("GPL v2");
181