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
 33struct moxart_mdio_data {
 34	void __iomem		*base;
 35};
 36
 37static 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
 65static 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
 97static 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
114static 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	bus->irq = devm_kzalloc(&pdev->dev, sizeof(int) * PHY_MAX_ADDR,
134			GFP_KERNEL);
135	if (!bus->irq) {
136		ret = -ENOMEM;
137		goto err_out_free_mdiobus;
138	}
139
140	/* Setting PHY_IGNORE_INTERRUPT here even if it has no effect,
141	 * of_mdiobus_register() sets these PHY_POLL.
142	 * Ideally, the interrupt from MAC controller could be used to
143	 * detect link state changes, not polling, i.e. if there was
144	 * a way phy_driver could set PHY_HAS_INTERRUPT but have that
145	 * interrupt handled in ethernet drivercode.
146	 */
147	for (i = 0; i < PHY_MAX_ADDR; i++)
148		bus->irq[i] = PHY_IGNORE_INTERRUPT;
149
150	data = bus->priv;
151	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
152	data->base = devm_ioremap_resource(&pdev->dev, res);
153	if (IS_ERR(data->base)) {
154		ret = PTR_ERR(data->base);
155		goto err_out_free_mdiobus;
156	}
157
158	ret = of_mdiobus_register(bus, np);
159	if (ret < 0)
160		goto err_out_free_mdiobus;
161
162	platform_set_drvdata(pdev, bus);
163
164	return 0;
165
166err_out_free_mdiobus:
167	mdiobus_free(bus);
168	return ret;
169}
170
171static int moxart_mdio_remove(struct platform_device *pdev)
172{
173	struct mii_bus *bus = platform_get_drvdata(pdev);
174
175	mdiobus_unregister(bus);
176	mdiobus_free(bus);
177
178	return 0;
179}
180
181static const struct of_device_id moxart_mdio_dt_ids[] = {
182	{ .compatible = "moxa,moxart-mdio" },
183	{ }
184};
185MODULE_DEVICE_TABLE(of, moxart_mdio_dt_ids);
186
187static struct platform_driver moxart_mdio_driver = {
188	.probe = moxart_mdio_probe,
189	.remove = moxart_mdio_remove,
190	.driver = {
191		.name = "moxart-mdio",
192		.of_match_table = moxart_mdio_dt_ids,
193	},
194};
195
196module_platform_driver(moxart_mdio_driver);
197
198MODULE_DESCRIPTION("MOXA ART MDIO interface driver");
199MODULE_AUTHOR("Jonas Jensen <jonas.jensen@gmail.com>");
200MODULE_LICENSE("GPL");