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	struct gpio_desc *mdc, *mdio, *mdo;
 36};
 37
 38static void *mdio_gpio_of_get_data(struct platform_device *pdev)
 39{
 40	struct device_node *np = pdev->dev.of_node;
 41	struct mdio_gpio_platform_data *pdata;
 42	enum of_gpio_flags flags;
 43	int ret;
 44
 45	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
 46	if (!pdata)
 47		return NULL;
 48
 49	ret = of_get_gpio_flags(np, 0, &flags);
 50	if (ret < 0)
 51		return NULL;
 52
 53	pdata->mdc = ret;
 54	pdata->mdc_active_low = flags & OF_GPIO_ACTIVE_LOW;
 55
 56	ret = of_get_gpio_flags(np, 1, &flags);
 57	if (ret < 0)
 58		return NULL;
 59	pdata->mdio = ret;
 60	pdata->mdio_active_low = flags & OF_GPIO_ACTIVE_LOW;
 61
 62	ret = of_get_gpio_flags(np, 2, &flags);
 63	if (ret > 0) {
 64		pdata->mdo = ret;
 65		pdata->mdo_active_low = flags & OF_GPIO_ACTIVE_LOW;
 66	}
 67
 68	return pdata;
 69}
 70
 71static void mdio_dir(struct mdiobb_ctrl *ctrl, int dir)
 72{
 73	struct mdio_gpio_info *bitbang =
 74		container_of(ctrl, struct mdio_gpio_info, ctrl);
 75
 76	if (bitbang->mdo) {
 77		/* Separate output pin. Always set its value to high
 78		 * when changing direction. If direction is input,
 79		 * assume the pin serves as pull-up. If direction is
 80		 * output, the default value is high.
 81		 */
 82		gpiod_set_value(bitbang->mdo, 1);
 83		return;
 84	}
 85
 86	if (dir)
 87		gpiod_direction_output(bitbang->mdio, 1);
 88	else
 89		gpiod_direction_input(bitbang->mdio);
 90}
 91
 92static int mdio_get(struct mdiobb_ctrl *ctrl)
 93{
 94	struct mdio_gpio_info *bitbang =
 95		container_of(ctrl, struct mdio_gpio_info, ctrl);
 96
 97	return gpiod_get_value(bitbang->mdio);
 98}
 99
100static void mdio_set(struct mdiobb_ctrl *ctrl, int what)
101{
102	struct mdio_gpio_info *bitbang =
103		container_of(ctrl, struct mdio_gpio_info, ctrl);
104
105	if (bitbang->mdo)
106		gpiod_set_value(bitbang->mdo, what);
107	else
108		gpiod_set_value(bitbang->mdio, what);
109}
110
111static void mdc_set(struct mdiobb_ctrl *ctrl, int what)
112{
113	struct mdio_gpio_info *bitbang =
114		container_of(ctrl, struct mdio_gpio_info, ctrl);
115
116	gpiod_set_value(bitbang->mdc, what);
117}
118
119static const struct mdiobb_ops mdio_gpio_ops = {
120	.owner = THIS_MODULE,
121	.set_mdc = mdc_set,
122	.set_mdio_dir = mdio_dir,
123	.set_mdio_data = mdio_set,
124	.get_mdio_data = mdio_get,
125};
126
127static struct mii_bus *mdio_gpio_bus_init(struct device *dev,
128					  struct mdio_gpio_platform_data *pdata,
129					  int bus_id)
130{
131	struct mii_bus *new_bus;
132	struct mdio_gpio_info *bitbang;
133	int i;
134	int mdc, mdio, mdo;
135	unsigned long mdc_flags = GPIOF_OUT_INIT_LOW;
136	unsigned long mdio_flags = GPIOF_DIR_IN;
137	unsigned long mdo_flags = GPIOF_OUT_INIT_HIGH;
138
139	bitbang = devm_kzalloc(dev, sizeof(*bitbang), GFP_KERNEL);
140	if (!bitbang)
141		goto out;
142
143	bitbang->ctrl.ops = &mdio_gpio_ops;
144	bitbang->ctrl.reset = pdata->reset;
145	mdc = pdata->mdc;
146	bitbang->mdc = gpio_to_desc(mdc);
147	if (pdata->mdc_active_low)
148		mdc_flags = GPIOF_OUT_INIT_HIGH | GPIOF_ACTIVE_LOW;
149	mdio = pdata->mdio;
150	bitbang->mdio = gpio_to_desc(mdio);
151	if (pdata->mdio_active_low)
152		mdio_flags |= GPIOF_ACTIVE_LOW;
153	mdo = pdata->mdo;
154	if (mdo) {
155		bitbang->mdo = gpio_to_desc(mdo);
156		if (pdata->mdo_active_low)
157			mdo_flags = GPIOF_OUT_INIT_LOW | GPIOF_ACTIVE_LOW;
158	}
159
160	new_bus = alloc_mdio_bitbang(&bitbang->ctrl);
161	if (!new_bus)
162		goto out;
163
164	new_bus->name = "GPIO Bitbanged MDIO",
165
166	new_bus->phy_mask = pdata->phy_mask;
167	new_bus->phy_ignore_ta_mask = pdata->phy_ignore_ta_mask;
168	memcpy(new_bus->irq, pdata->irqs, sizeof(new_bus->irq));
169	new_bus->parent = dev;
170
171	if (new_bus->phy_mask == ~0)
172		goto out_free_bus;
173
174	for (i = 0; i < PHY_MAX_ADDR; i++)
175		if (!new_bus->irq[i])
176			new_bus->irq[i] = PHY_POLL;
177
178	if (bus_id != -1)
179		snprintf(new_bus->id, MII_BUS_ID_SIZE, "gpio-%x", bus_id);
180	else
181		strncpy(new_bus->id, "gpio", MII_BUS_ID_SIZE);
182
183	if (devm_gpio_request_one(dev, mdc, mdc_flags, "mdc"))
184		goto out_free_bus;
185
186	if (devm_gpio_request_one(dev, mdio, mdio_flags, "mdio"))
187		goto out_free_bus;
188
189	if (mdo && devm_gpio_request_one(dev, mdo, mdo_flags, "mdo"))
190		goto out_free_bus;
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");