1 /* MOXA ART Ethernet (RTL8201CP) MDIO interface driver
2 *
3 * Copyright (C) 2013 Jonas Jensen <jonas.jensen@gmail.com>
4 *
5 * This file is licensed under the terms of the GNU General Public
6 * License version 2. This program is licensed "as is" without any
7 * warranty of any kind, whether express or implied.
8 */
9
10 #include <linux/delay.h>
11 #include <linux/kernel.h>
12 #include <linux/module.h>
13 #include <linux/mutex.h>
14 #include <linux/of_address.h>
15 #include <linux/of_mdio.h>
16 #include <linux/phy.h>
17 #include <linux/platform_device.h>
18 #include <linux/regulator/consumer.h>
19
20 #define REG_PHY_CTRL 0
21 #define REG_PHY_WRITE_DATA 4
22
23 /* REG_PHY_CTRL */
24 #define MIIWR BIT(27) /* init write sequence (auto cleared)*/
25 #define MIIRD BIT(26)
26 #define REGAD_MASK 0x3e00000
27 #define PHYAD_MASK 0x1f0000
28 #define MIIRDATA_MASK 0xffff
29
30 /* REG_PHY_WRITE_DATA */
31 #define MIIWDATA_MASK 0xffff
32
33 struct moxart_mdio_data {
34 void __iomem *base;
35 };
36
moxart_mdio_read(struct mii_bus * bus,int mii_id,int regnum)37 static int moxart_mdio_read(struct mii_bus *bus, int mii_id, int regnum)
38 {
39 struct moxart_mdio_data *data = bus->priv;
40 u32 ctrl = 0;
41 unsigned int count = 5;
42
43 dev_dbg(&bus->dev, "%s\n", __func__);
44
45 ctrl |= MIIRD | ((mii_id << 16) & PHYAD_MASK) |
46 ((regnum << 21) & REGAD_MASK);
47
48 writel(ctrl, data->base + REG_PHY_CTRL);
49
50 do {
51 ctrl = readl(data->base + REG_PHY_CTRL);
52
53 if (!(ctrl & MIIRD))
54 return ctrl & MIIRDATA_MASK;
55
56 mdelay(10);
57 count--;
58 } while (count > 0);
59
60 dev_dbg(&bus->dev, "%s timed out\n", __func__);
61
62 return -ETIMEDOUT;
63 }
64
moxart_mdio_write(struct mii_bus * bus,int mii_id,int regnum,u16 value)65 static int moxart_mdio_write(struct mii_bus *bus, int mii_id,
66 int regnum, u16 value)
67 {
68 struct moxart_mdio_data *data = bus->priv;
69 u32 ctrl = 0;
70 unsigned int count = 5;
71
72 dev_dbg(&bus->dev, "%s\n", __func__);
73
74 ctrl |= MIIWR | ((mii_id << 16) & PHYAD_MASK) |
75 ((regnum << 21) & REGAD_MASK);
76
77 value &= MIIWDATA_MASK;
78
79 writel(value, data->base + REG_PHY_WRITE_DATA);
80 writel(ctrl, data->base + REG_PHY_CTRL);
81
82 do {
83 ctrl = readl(data->base + REG_PHY_CTRL);
84
85 if (!(ctrl & MIIWR))
86 return 0;
87
88 mdelay(10);
89 count--;
90 } while (count > 0);
91
92 dev_dbg(&bus->dev, "%s timed out\n", __func__);
93
94 return -ETIMEDOUT;
95 }
96
moxart_mdio_reset(struct mii_bus * bus)97 static int moxart_mdio_reset(struct mii_bus *bus)
98 {
99 int data, i;
100
101 for (i = 0; i < PHY_MAX_ADDR; i++) {
102 data = moxart_mdio_read(bus, i, MII_BMCR);
103 if (data < 0)
104 continue;
105
106 data |= BMCR_RESET;
107 if (moxart_mdio_write(bus, i, MII_BMCR, data) < 0)
108 continue;
109 }
110
111 return 0;
112 }
113
moxart_mdio_probe(struct platform_device * pdev)114 static int moxart_mdio_probe(struct platform_device *pdev)
115 {
116 struct device_node *np = pdev->dev.of_node;
117 struct mii_bus *bus;
118 struct moxart_mdio_data *data;
119 struct resource *res;
120 int ret, i;
121
122 bus = mdiobus_alloc_size(sizeof(*data));
123 if (!bus)
124 return -ENOMEM;
125
126 bus->name = "MOXA ART Ethernet MII";
127 bus->read = &moxart_mdio_read;
128 bus->write = &moxart_mdio_write;
129 bus->reset = &moxart_mdio_reset;
130 snprintf(bus->id, MII_BUS_ID_SIZE, "%s-%d-mii", pdev->name, pdev->id);
131 bus->parent = &pdev->dev;
132
133 /* Setting PHY_IGNORE_INTERRUPT here even if it has no effect,
134 * of_mdiobus_register() sets these PHY_POLL.
135 * Ideally, the interrupt from MAC controller could be used to
136 * detect link state changes, not polling, i.e. if there was
137 * a way phy_driver could set PHY_HAS_INTERRUPT but have that
138 * interrupt handled in ethernet drivercode.
139 */
140 for (i = 0; i < PHY_MAX_ADDR; i++)
141 bus->irq[i] = PHY_IGNORE_INTERRUPT;
142
143 data = bus->priv;
144 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
145 data->base = devm_ioremap_resource(&pdev->dev, res);
146 if (IS_ERR(data->base)) {
147 ret = PTR_ERR(data->base);
148 goto err_out_free_mdiobus;
149 }
150
151 ret = of_mdiobus_register(bus, np);
152 if (ret < 0)
153 goto err_out_free_mdiobus;
154
155 platform_set_drvdata(pdev, bus);
156
157 return 0;
158
159 err_out_free_mdiobus:
160 mdiobus_free(bus);
161 return ret;
162 }
163
moxart_mdio_remove(struct platform_device * pdev)164 static int moxart_mdio_remove(struct platform_device *pdev)
165 {
166 struct mii_bus *bus = platform_get_drvdata(pdev);
167
168 mdiobus_unregister(bus);
169 mdiobus_free(bus);
170
171 return 0;
172 }
173
174 static const struct of_device_id moxart_mdio_dt_ids[] = {
175 { .compatible = "moxa,moxart-mdio" },
176 { }
177 };
178 MODULE_DEVICE_TABLE(of, moxart_mdio_dt_ids);
179
180 static struct platform_driver moxart_mdio_driver = {
181 .probe = moxart_mdio_probe,
182 .remove = moxart_mdio_remove,
183 .driver = {
184 .name = "moxart-mdio",
185 .of_match_table = moxart_mdio_dt_ids,
186 },
187 };
188
189 module_platform_driver(moxart_mdio_driver);
190
191 MODULE_DESCRIPTION("MOXA ART MDIO interface driver");
192 MODULE_AUTHOR("Jonas Jensen <jonas.jensen@gmail.com>");
193 MODULE_LICENSE("GPL");
194