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
34 struct sun4i_mdio_data {
35 void __iomem *membase;
36 struct regulator *regulator;
37 };
38
sun4i_mdio_read(struct mii_bus * bus,int mii_id,int regnum)39 static 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
sun4i_mdio_write(struct mii_bus * bus,int mii_id,int regnum,u16 value)66 static 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
sun4i_mdio_probe(struct platform_device * pdev)93 static 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 } else {
126 ret = regulator_enable(data->regulator);
127 if (ret)
128 goto err_out_free_mdiobus;
129 }
130
131 ret = of_mdiobus_register(bus, np);
132 if (ret < 0)
133 goto err_out_disable_regulator;
134
135 platform_set_drvdata(pdev, bus);
136
137 return 0;
138
139 err_out_disable_regulator:
140 regulator_disable(data->regulator);
141 err_out_free_mdiobus:
142 mdiobus_free(bus);
143 return ret;
144 }
145
sun4i_mdio_remove(struct platform_device * pdev)146 static int sun4i_mdio_remove(struct platform_device *pdev)
147 {
148 struct mii_bus *bus = platform_get_drvdata(pdev);
149
150 mdiobus_unregister(bus);
151 mdiobus_free(bus);
152
153 return 0;
154 }
155
156 static 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 };
163 MODULE_DEVICE_TABLE(of, sun4i_mdio_dt_ids);
164
165 static struct platform_driver sun4i_mdio_driver = {
166 .probe = sun4i_mdio_probe,
167 .remove = sun4i_mdio_remove,
168 .driver = {
169 .name = "sun4i-mdio",
170 .of_match_table = sun4i_mdio_dt_ids,
171 },
172 };
173
174 module_platform_driver(sun4i_mdio_driver);
175
176 MODULE_DESCRIPTION("Allwinner EMAC MDIO interface driver");
177 MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
178 MODULE_LICENSE("GPL");
179