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

source code of linux/drivers/net/mdio/mdio-moxart.c