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/platform_data/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->phy_ignore_ta_mask = pdata->phy_ignore_ta_mask;
162	memcpy(new_bus->irq, pdata->irqs, sizeof(new_bus->irq));
163	new_bus->parent = dev;
164
165	if (new_bus->phy_mask == ~0)
166		goto out_free_bus;
167
168	for (i = 0; i < PHY_MAX_ADDR; i++)
169		if (!new_bus->irq[i])
170			new_bus->irq[i] = PHY_POLL;
171
172	if (bus_id != -1)
173		snprintf(new_bus->id, MII_BUS_ID_SIZE, "gpio-%x", bus_id);
174	else
175		strncpy(new_bus->id, "gpio", MII_BUS_ID_SIZE);
176
177	if (devm_gpio_request(dev, bitbang->mdc, "mdc"))
178		goto out_free_bus;
179
180	if (devm_gpio_request(dev, bitbang->mdio, "mdio"))
181		goto out_free_bus;
182
183	if (bitbang->mdo) {
184		if (devm_gpio_request(dev, bitbang->mdo, "mdo"))
185			goto out_free_bus;
186		gpio_direction_output(bitbang->mdo, 1);
187		gpio_direction_input(bitbang->mdio);
188	}
189
190	gpio_direction_output(bitbang->mdc, 0);
191
192	dev_set_drvdata(dev, new_bus);
193
194	return new_bus;
195
196out_free_bus:
197	free_mdio_bitbang(new_bus);
198out:
199	return NULL;
200}
201
202static void mdio_gpio_bus_deinit(struct device *dev)
203{
204	struct mii_bus *bus = dev_get_drvdata(dev);
205
206	free_mdio_bitbang(bus);
207}
208
209static void mdio_gpio_bus_destroy(struct device *dev)
210{
211	struct mii_bus *bus = dev_get_drvdata(dev);
212
213	mdiobus_unregister(bus);
214	mdio_gpio_bus_deinit(dev);
215}
216
217static int mdio_gpio_probe(struct platform_device *pdev)
218{
219	struct mdio_gpio_platform_data *pdata;
220	struct mii_bus *new_bus;
221	int ret, bus_id;
222
223	if (pdev->dev.of_node) {
224		pdata = mdio_gpio_of_get_data(pdev);
225		bus_id = of_alias_get_id(pdev->dev.of_node, "mdio-gpio");
226		if (bus_id < 0) {
227			dev_warn(&pdev->dev, "failed to get alias id\n");
228			bus_id = 0;
229		}
230	} else {
231		pdata = dev_get_platdata(&pdev->dev);
232		bus_id = pdev->id;
233	}
234
235	if (!pdata)
236		return -ENODEV;
237
238	new_bus = mdio_gpio_bus_init(&pdev->dev, pdata, bus_id);
239	if (!new_bus)
240		return -ENODEV;
241
242	if (pdev->dev.of_node)
243		ret = of_mdiobus_register(new_bus, pdev->dev.of_node);
244	else
245		ret = mdiobus_register(new_bus);
246
247	if (ret)
248		mdio_gpio_bus_deinit(&pdev->dev);
249
250	return ret;
251}
252
253static int mdio_gpio_remove(struct platform_device *pdev)
254{
255	mdio_gpio_bus_destroy(&pdev->dev);
256
257	return 0;
258}
259
260static const struct of_device_id mdio_gpio_of_match[] = {
261	{ .compatible = "virtual,mdio-gpio", },
262	{ /* sentinel */ }
263};
264MODULE_DEVICE_TABLE(of, mdio_gpio_of_match);
265
266static struct platform_driver mdio_gpio_driver = {
267	.probe = mdio_gpio_probe,
268	.remove = mdio_gpio_remove,
269	.driver		= {
270		.name	= "mdio-gpio",
271		.of_match_table = mdio_gpio_of_match,
272	},
273};
274
275module_platform_driver(mdio_gpio_driver);
276
277MODULE_ALIAS("platform:mdio-gpio");
278MODULE_AUTHOR("Laurent Pinchart, Paulius Zaleckas");
279MODULE_LICENSE("GPL");
280MODULE_DESCRIPTION("Generic driver for MDIO bus emulation using GPIO");