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(bitbang->mdo, 1 ^ bitbang->mdo_active_low);
 84		return;
 85	}
 86
 87	if (dir)
 88		gpio_direction_output(bitbang->mdio,
 89				      1 ^ bitbang->mdio_active_low);
 90	else
 91		gpio_direction_input(bitbang->mdio);
 92}
 93
 94static int mdio_get(struct mdiobb_ctrl *ctrl)
 95{
 96	struct mdio_gpio_info *bitbang =
 97		container_of(ctrl, struct mdio_gpio_info, ctrl);
 98
 99	return gpio_get_value(bitbang->mdio) ^ bitbang->mdio_active_low;
100}
101
102static void mdio_set(struct mdiobb_ctrl *ctrl, int what)
103{
104	struct mdio_gpio_info *bitbang =
105		container_of(ctrl, struct mdio_gpio_info, ctrl);
106
107	if (bitbang->mdo)
108		gpio_set_value(bitbang->mdo, what ^ bitbang->mdo_active_low);
109	else
110		gpio_set_value(bitbang->mdio, what ^ bitbang->mdio_active_low);
111}
112
113static void mdc_set(struct mdiobb_ctrl *ctrl, int what)
114{
115	struct mdio_gpio_info *bitbang =
116		container_of(ctrl, struct mdio_gpio_info, ctrl);
117
118	gpio_set_value(bitbang->mdc, what ^ bitbang->mdc_active_low);
119}
120
121static struct mdiobb_ops mdio_gpio_ops = {
122	.owner = THIS_MODULE,
123	.set_mdc = mdc_set,
124	.set_mdio_dir = mdio_dir,
125	.set_mdio_data = mdio_set,
126	.get_mdio_data = mdio_get,
127};
128
129static struct mii_bus *mdio_gpio_bus_init(struct device *dev,
130					  struct mdio_gpio_platform_data *pdata,
131					  int bus_id)
132{
133	struct mii_bus *new_bus;
134	struct mdio_gpio_info *bitbang;
135	int i;
136
137	bitbang = devm_kzalloc(dev, sizeof(*bitbang), GFP_KERNEL);
138	if (!bitbang)
139		goto out;
140
141	bitbang->ctrl.ops = &mdio_gpio_ops;
142	bitbang->ctrl.reset = pdata->reset;
143	bitbang->mdc = pdata->mdc;
144	bitbang->mdc_active_low = pdata->mdc_active_low;
145	bitbang->mdio = pdata->mdio;
146	bitbang->mdio_active_low = pdata->mdio_active_low;
147	bitbang->mdo = pdata->mdo;
148	bitbang->mdo_active_low = pdata->mdo_active_low;
149
150	new_bus = alloc_mdio_bitbang(&bitbang->ctrl);
151	if (!new_bus)
152		goto out;
153
154	new_bus->name = "GPIO Bitbanged MDIO",
155
156	new_bus->phy_mask = pdata->phy_mask;
157	new_bus->irq = pdata->irqs;
158	new_bus->parent = dev;
159
160	if (new_bus->phy_mask == ~0)
161		goto out_free_bus;
162
163	for (i = 0; i < PHY_MAX_ADDR; i++)
164		if (!new_bus->irq[i])
165			new_bus->irq[i] = PHY_POLL;
166
167	snprintf(new_bus->id, MII_BUS_ID_SIZE, "gpio-%x", bus_id);
168
169	if (devm_gpio_request(dev, bitbang->mdc, "mdc"))
170		goto out_free_bus;
171
172	if (devm_gpio_request(dev, bitbang->mdio, "mdio"))
173		goto out_free_bus;
174
175	if (bitbang->mdo) {
176		if (devm_gpio_request(dev, bitbang->mdo, "mdo"))
177			goto out_free_bus;
178		gpio_direction_output(bitbang->mdo, 1);
179		gpio_direction_input(bitbang->mdio);
180	}
181
182	gpio_direction_output(bitbang->mdc, 0);
183
184	dev_set_drvdata(dev, new_bus);
185
186	return new_bus;
187
188out_free_bus:
189	free_mdio_bitbang(new_bus);
190out:
191	return NULL;
192}
193
194static void mdio_gpio_bus_deinit(struct device *dev)
195{
196	struct mii_bus *bus = dev_get_drvdata(dev);
197
198	free_mdio_bitbang(bus);
199}
200
201static void mdio_gpio_bus_destroy(struct device *dev)
202{
203	struct mii_bus *bus = dev_get_drvdata(dev);
204
205	mdiobus_unregister(bus);
206	mdio_gpio_bus_deinit(dev);
207}
208
209static int mdio_gpio_probe(struct platform_device *pdev)
210{
211	struct mdio_gpio_platform_data *pdata;
212	struct mii_bus *new_bus;
213	int ret, bus_id;
214
215	if (pdev->dev.of_node) {
216		pdata = mdio_gpio_of_get_data(pdev);
217		bus_id = of_alias_get_id(pdev->dev.of_node, "mdio-gpio");
218		if (bus_id < 0) {
219			dev_warn(&pdev->dev, "failed to get alias id\n");
220			bus_id = 0;
221		}
222	} else {
223		pdata = dev_get_platdata(&pdev->dev);
224		bus_id = pdev->id;
225	}
226
227	if (!pdata)
228		return -ENODEV;
229
230	new_bus = mdio_gpio_bus_init(&pdev->dev, pdata, bus_id);
231	if (!new_bus)
232		return -ENODEV;
233
234	if (pdev->dev.of_node)
235		ret = of_mdiobus_register(new_bus, pdev->dev.of_node);
236	else
237		ret = mdiobus_register(new_bus);
238
239	if (ret)
240		mdio_gpio_bus_deinit(&pdev->dev);
241
242	return ret;
243}
244
245static int mdio_gpio_remove(struct platform_device *pdev)
246{
247	mdio_gpio_bus_destroy(&pdev->dev);
248
249	return 0;
250}
251
252static struct of_device_id mdio_gpio_of_match[] = {
253	{ .compatible = "virtual,mdio-gpio", },
254	{ /* sentinel */ }
255};
256
257static struct platform_driver mdio_gpio_driver = {
258	.probe = mdio_gpio_probe,
259	.remove = mdio_gpio_remove,
260	.driver		= {
261		.name	= "mdio-gpio",
262		.owner	= THIS_MODULE,
263		.of_match_table = mdio_gpio_of_match,
264	},
265};
266
267module_platform_driver(mdio_gpio_driver);
268
269MODULE_ALIAS("platform:mdio-gpio");
270MODULE_AUTHOR("Laurent Pinchart, Paulius Zaleckas");
271MODULE_LICENSE("GPL");
272MODULE_DESCRIPTION("Generic driver for MDIO bus emulation using GPIO");