1/*
2 * GPIO based MDIO bitbang driver.
3 * Supports OpenFirmware.
4 *
5 * Copyright (c) 2008 CSE Semaphore Belgium.
6 *  by Laurent Pinchart <laurentp@cse-semaphore.com>
7 *
8 * Copyright (C) 2008, Paulius Zaleckas <paulius.zaleckas@teltonika.lt>
9 *
10 * Based on earlier work by
11 *
12 * Copyright (c) 2003 Intracom S.A.
13 *  by Pantelis Antoniou <panto@intracom.gr>
14 *
15 * 2005 (c) MontaVista Software, Inc.
16 * Vitaly Bordug <vbordug@ru.mvista.com>
17 *
18 * This file is licensed under the terms of the GNU General Public License
19 * version 2. This program is licensed "as is" without any warranty of any
20 * kind, whether express or implied.
21 */
22
23#include <linux/module.h>
24#include <linux/slab.h>
25#include <linux/interrupt.h>
26#include <linux/platform_device.h>
27#include <linux/gpio.h>
28#include <linux/mdio-gpio.h>
29
30#include <linux/of_gpio.h>
31#include <linux/of_mdio.h>
32
33struct mdio_gpio_info {
34	struct mdiobb_ctrl ctrl;
35	int mdc, mdio, mdo;
36	int mdc_active_low, mdio_active_low, mdo_active_low;
37};
38
39static void *mdio_gpio_of_get_data(struct platform_device *pdev)
40{
41	struct device_node *np = pdev->dev.of_node;
42	struct mdio_gpio_platform_data *pdata;
43	enum of_gpio_flags flags;
44	int ret;
45
46	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
47	if (!pdata)
48		return NULL;
49
50	ret = of_get_gpio_flags(np, 0, &flags);
51	if (ret < 0)
52		return NULL;
53
54	pdata->mdc = ret;
55	pdata->mdc_active_low = flags & OF_GPIO_ACTIVE_LOW;
56
57	ret = of_get_gpio_flags(np, 1, &flags);
58	if (ret < 0)
59		return NULL;
60	pdata->mdio = ret;
61	pdata->mdio_active_low = flags & OF_GPIO_ACTIVE_LOW;
62
63	ret = of_get_gpio_flags(np, 2, &flags);
64	if (ret > 0) {
65		pdata->mdo = ret;
66		pdata->mdo_active_low = flags & OF_GPIO_ACTIVE_LOW;
67	}
68
69	return pdata;
70}
71
72static void mdio_dir(struct mdiobb_ctrl *ctrl, int dir)
73{
74	struct mdio_gpio_info *bitbang =
75		container_of(ctrl, struct mdio_gpio_info, ctrl);
76
77	if (bitbang->mdo) {
78		/* Separate output pin. Always set its value to high
79		 * when changing direction. If direction is input,
80		 * assume the pin serves as pull-up. If direction is
81		 * output, the default value is high.
82		 */
83		gpio_set_value_cansleep(bitbang->mdo,
84					1 ^ bitbang->mdo_active_low);
85		return;
86	}
87
88	if (dir)
89		gpio_direction_output(bitbang->mdio,
90				      1 ^ bitbang->mdio_active_low);
91	else
92		gpio_direction_input(bitbang->mdio);
93}
94
95static int mdio_get(struct mdiobb_ctrl *ctrl)
96{
97	struct mdio_gpio_info *bitbang =
98		container_of(ctrl, struct mdio_gpio_info, ctrl);
99
100	return gpio_get_value_cansleep(bitbang->mdio) ^
101		bitbang->mdio_active_low;
102}
103
104static void mdio_set(struct mdiobb_ctrl *ctrl, int what)
105{
106	struct mdio_gpio_info *bitbang =
107		container_of(ctrl, struct mdio_gpio_info, ctrl);
108
109	if (bitbang->mdo)
110		gpio_set_value_cansleep(bitbang->mdo,
111					what ^ bitbang->mdo_active_low);
112	else
113		gpio_set_value_cansleep(bitbang->mdio,
114					what ^ bitbang->mdio_active_low);
115}
116
117static void mdc_set(struct mdiobb_ctrl *ctrl, int what)
118{
119	struct mdio_gpio_info *bitbang =
120		container_of(ctrl, struct mdio_gpio_info, ctrl);
121
122	gpio_set_value_cansleep(bitbang->mdc, what ^ bitbang->mdc_active_low);
123}
124
125static struct mdiobb_ops mdio_gpio_ops = {
126	.owner = THIS_MODULE,
127	.set_mdc = mdc_set,
128	.set_mdio_dir = mdio_dir,
129	.set_mdio_data = mdio_set,
130	.get_mdio_data = mdio_get,
131};
132
133static struct mii_bus *mdio_gpio_bus_init(struct device *dev,
134					  struct mdio_gpio_platform_data *pdata,
135					  int bus_id)
136{
137	struct mii_bus *new_bus;
138	struct mdio_gpio_info *bitbang;
139	int i;
140
141	bitbang = devm_kzalloc(dev, sizeof(*bitbang), GFP_KERNEL);
142	if (!bitbang)
143		goto out;
144
145	bitbang->ctrl.ops = &mdio_gpio_ops;
146	bitbang->ctrl.reset = pdata->reset;
147	bitbang->mdc = pdata->mdc;
148	bitbang->mdc_active_low = pdata->mdc_active_low;
149	bitbang->mdio = pdata->mdio;
150	bitbang->mdio_active_low = pdata->mdio_active_low;
151	bitbang->mdo = pdata->mdo;
152	bitbang->mdo_active_low = pdata->mdo_active_low;
153
154	new_bus = alloc_mdio_bitbang(&bitbang->ctrl);
155	if (!new_bus)
156		goto out;
157
158	new_bus->name = "GPIO Bitbanged MDIO",
159
160	new_bus->phy_mask = pdata->phy_mask;
161	new_bus->irq = pdata->irqs;
162	new_bus->parent = dev;
163
164	if (new_bus->phy_mask == ~0)
165		goto out_free_bus;
166
167	for (i = 0; i < PHY_MAX_ADDR; i++)
168		if (!new_bus->irq[i])
169			new_bus->irq[i] = PHY_POLL;
170
171	if (bus_id != -1)
172		snprintf(new_bus->id, MII_BUS_ID_SIZE, "gpio-%x", bus_id);
173	else
174		strncpy(new_bus->id, "gpio", MII_BUS_ID_SIZE);
175
176	if (devm_gpio_request(dev, bitbang->mdc, "mdc"))
177		goto out_free_bus;
178
179	if (devm_gpio_request(dev, bitbang->mdio, "mdio"))
180		goto out_free_bus;
181
182	if (bitbang->mdo) {
183		if (devm_gpio_request(dev, bitbang->mdo, "mdo"))
184			goto out_free_bus;
185		gpio_direction_output(bitbang->mdo, 1);
186		gpio_direction_input(bitbang->mdio);
187	}
188
189	gpio_direction_output(bitbang->mdc, 0);
190
191	dev_set_drvdata(dev, new_bus);
192
193	return new_bus;
194
195out_free_bus:
196	free_mdio_bitbang(new_bus);
197out:
198	return NULL;
199}
200
201static void mdio_gpio_bus_deinit(struct device *dev)
202{
203	struct mii_bus *bus = dev_get_drvdata(dev);
204
205	free_mdio_bitbang(bus);
206}
207
208static void mdio_gpio_bus_destroy(struct device *dev)
209{
210	struct mii_bus *bus = dev_get_drvdata(dev);
211
212	mdiobus_unregister(bus);
213	mdio_gpio_bus_deinit(dev);
214}
215
216static int mdio_gpio_probe(struct platform_device *pdev)
217{
218	struct mdio_gpio_platform_data *pdata;
219	struct mii_bus *new_bus;
220	int ret, bus_id;
221
222	if (pdev->dev.of_node) {
223		pdata = mdio_gpio_of_get_data(pdev);
224		bus_id = of_alias_get_id(pdev->dev.of_node, "mdio-gpio");
225		if (bus_id < 0) {
226			dev_warn(&pdev->dev, "failed to get alias id\n");
227			bus_id = 0;
228		}
229	} else {
230		pdata = dev_get_platdata(&pdev->dev);
231		bus_id = pdev->id;
232	}
233
234	if (!pdata)
235		return -ENODEV;
236
237	new_bus = mdio_gpio_bus_init(&pdev->dev, pdata, bus_id);
238	if (!new_bus)
239		return -ENODEV;
240
241	if (pdev->dev.of_node)
242		ret = of_mdiobus_register(new_bus, pdev->dev.of_node);
243	else
244		ret = mdiobus_register(new_bus);
245
246	if (ret)
247		mdio_gpio_bus_deinit(&pdev->dev);
248
249	return ret;
250}
251
252static int mdio_gpio_remove(struct platform_device *pdev)
253{
254	mdio_gpio_bus_destroy(&pdev->dev);
255
256	return 0;
257}
258
259static const struct of_device_id mdio_gpio_of_match[] = {
260	{ .compatible = "virtual,mdio-gpio", },
261	{ /* sentinel */ }
262};
263
264static struct platform_driver mdio_gpio_driver = {
265	.probe = mdio_gpio_probe,
266	.remove = mdio_gpio_remove,
267	.driver		= {
268		.name	= "mdio-gpio",
269		.of_match_table = mdio_gpio_of_match,
270	},
271};
272
273module_platform_driver(mdio_gpio_driver);
274
275MODULE_ALIAS("platform:mdio-gpio");
276MODULE_AUTHOR("Laurent Pinchart, Paulius Zaleckas");
277MODULE_LICENSE("GPL");
278MODULE_DESCRIPTION("Generic driver for MDIO bus emulation using GPIO");
279