1 // SPDX-License-Identifier: GPL-2.0
2 /* MOXA ART Ethernet (RTL8201CP) MDIO interface driver
3 *
4 * Copyright (C) 2013 Jonas Jensen <jonas.jensen@gmail.com>
5 */
6
7 #include <linux/delay.h>
8 #include <linux/kernel.h>
9 #include <linux/module.h>
10 #include <linux/mutex.h>
11 #include <linux/of_address.h>
12 #include <linux/of_mdio.h>
13 #include <linux/phy.h>
14 #include <linux/platform_device.h>
15 #include <linux/regulator/consumer.h>
16
17 #define REG_PHY_CTRL 0
18 #define REG_PHY_WRITE_DATA 4
19
20 /* REG_PHY_CTRL */
21 #define MIIWR BIT(27) /* init write sequence (auto cleared)*/
22 #define MIIRD BIT(26)
23 #define REGAD_MASK 0x3e00000
24 #define PHYAD_MASK 0x1f0000
25 #define MIIRDATA_MASK 0xffff
26
27 /* REG_PHY_WRITE_DATA */
28 #define MIIWDATA_MASK 0xffff
29
30 struct moxart_mdio_data {
31 void __iomem *base;
32 };
33
moxart_mdio_read(struct mii_bus * bus,int mii_id,int regnum)34 static int moxart_mdio_read(struct mii_bus *bus, int mii_id, int regnum)
35 {
36 struct moxart_mdio_data *data = bus->priv;
37 u32 ctrl = 0;
38 unsigned int count = 5;
39
40 dev_dbg(&bus->dev, "%s\n", __func__);
41
42 ctrl |= MIIRD | ((mii_id << 16) & PHYAD_MASK) |
43 ((regnum << 21) & REGAD_MASK);
44
45 writel(ctrl, data->base + REG_PHY_CTRL);
46
47 do {
48 ctrl = readl(data->base + REG_PHY_CTRL);
49
50 if (!(ctrl & MIIRD))
51 return ctrl & MIIRDATA_MASK;
52
53 mdelay(10);
54 count--;
55 } while (count > 0);
56
57 dev_dbg(&bus->dev, "%s timed out\n", __func__);
58
59 return -ETIMEDOUT;
60 }
61
moxart_mdio_write(struct mii_bus * bus,int mii_id,int regnum,u16 value)62 static int moxart_mdio_write(struct mii_bus *bus, int mii_id,
63 int regnum, u16 value)
64 {
65 struct moxart_mdio_data *data = bus->priv;
66 u32 ctrl = 0;
67 unsigned int count = 5;
68
69 dev_dbg(&bus->dev, "%s\n", __func__);
70
71 ctrl |= MIIWR | ((mii_id << 16) & PHYAD_MASK) |
72 ((regnum << 21) & REGAD_MASK);
73
74 value &= MIIWDATA_MASK;
75
76 writel(value, data->base + REG_PHY_WRITE_DATA);
77 writel(ctrl, data->base + REG_PHY_CTRL);
78
79 do {
80 ctrl = readl(data->base + REG_PHY_CTRL);
81
82 if (!(ctrl & MIIWR))
83 return 0;
84
85 mdelay(10);
86 count--;
87 } while (count > 0);
88
89 dev_dbg(&bus->dev, "%s timed out\n", __func__);
90
91 return -ETIMEDOUT;
92 }
93
moxart_mdio_reset(struct mii_bus * bus)94 static int moxart_mdio_reset(struct mii_bus *bus)
95 {
96 int data, i;
97
98 for (i = 0; i < PHY_MAX_ADDR; i++) {
99 data = moxart_mdio_read(bus, i, MII_BMCR);
100 if (data < 0)
101 continue;
102
103 data |= BMCR_RESET;
104 if (moxart_mdio_write(bus, i, MII_BMCR, data) < 0)
105 continue;
106 }
107
108 return 0;
109 }
110
moxart_mdio_probe(struct platform_device * pdev)111 static int moxart_mdio_probe(struct platform_device *pdev)
112 {
113 struct device_node *np = pdev->dev.of_node;
114 struct mii_bus *bus;
115 struct moxart_mdio_data *data;
116 int ret, i;
117
118 bus = mdiobus_alloc_size(sizeof(*data));
119 if (!bus)
120 return -ENOMEM;
121
122 bus->name = "MOXA ART Ethernet MII";
123 bus->read = &moxart_mdio_read;
124 bus->write = &moxart_mdio_write;
125 bus->reset = &moxart_mdio_reset;
126 snprintf(bus->id, MII_BUS_ID_SIZE, "%s-%d-mii", pdev->name, pdev->id);
127 bus->parent = &pdev->dev;
128
129 /* Setting PHY_IGNORE_INTERRUPT here even if it has no effect,
130 * of_mdiobus_register() sets these PHY_POLL.
131 * Ideally, the interrupt from MAC controller could be used to
132 * detect link state changes, not polling, i.e. if there was
133 * a way phy_driver could set PHY_HAS_INTERRUPT but have that
134 * interrupt handled in ethernet drivercode.
135 */
136 for (i = 0; i < PHY_MAX_ADDR; i++)
137 bus->irq[i] = PHY_IGNORE_INTERRUPT;
138
139 data = bus->priv;
140 data->base = devm_platform_ioremap_resource(pdev, 0);
141 if (IS_ERR(data->base)) {
142 ret = PTR_ERR(data->base);
143 goto err_out_free_mdiobus;
144 }
145
146 ret = of_mdiobus_register(bus, np);
147 if (ret < 0)
148 goto err_out_free_mdiobus;
149
150 platform_set_drvdata(pdev, bus);
151
152 return 0;
153
154 err_out_free_mdiobus:
155 mdiobus_free(bus);
156 return ret;
157 }
158
moxart_mdio_remove(struct platform_device * pdev)159 static int moxart_mdio_remove(struct platform_device *pdev)
160 {
161 struct mii_bus *bus = platform_get_drvdata(pdev);
162
163 mdiobus_unregister(bus);
164 mdiobus_free(bus);
165
166 return 0;
167 }
168
169 static const struct of_device_id moxart_mdio_dt_ids[] = {
170 { .compatible = "moxa,moxart-mdio" },
171 { }
172 };
173 MODULE_DEVICE_TABLE(of, moxart_mdio_dt_ids);
174
175 static struct platform_driver moxart_mdio_driver = {
176 .probe = moxart_mdio_probe,
177 .remove = moxart_mdio_remove,
178 .driver = {
179 .name = "moxart-mdio",
180 .of_match_table = moxart_mdio_dt_ids,
181 },
182 };
183
184 module_platform_driver(moxart_mdio_driver);
185
186 MODULE_DESCRIPTION("MOXA ART MDIO interface driver");
187 MODULE_AUTHOR("Jonas Jensen <jonas.jensen@gmail.com>");
188 MODULE_LICENSE("GPL v2");
189
