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
33 struct 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
mdio_gpio_of_get_data(struct platform_device * pdev)39 static 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
mdio_dir(struct mdiobb_ctrl * ctrl,int dir)72 static 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
mdio_get(struct mdiobb_ctrl * ctrl)95 static 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
mdio_set(struct mdiobb_ctrl * ctrl,int what)104 static 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
mdc_set(struct mdiobb_ctrl * ctrl,int what)117 static 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
125 static 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
mdio_gpio_bus_init(struct device * dev,struct mdio_gpio_platform_data * pdata,int bus_id)133 static 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
195 out_free_bus:
196 free_mdio_bitbang(new_bus);
197 out:
198 return NULL;
199 }
200
mdio_gpio_bus_deinit(struct device * dev)201 static 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
mdio_gpio_bus_destroy(struct device * dev)208 static 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
mdio_gpio_probe(struct platform_device * pdev)216 static 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
mdio_gpio_remove(struct platform_device * pdev)252 static int mdio_gpio_remove(struct platform_device *pdev)
253 {
254 mdio_gpio_bus_destroy(&pdev->dev);
255
256 return 0;
257 }
258
259 static const struct of_device_id mdio_gpio_of_match[] = {
260 { .compatible = "virtual,mdio-gpio", },
261 { /* sentinel */ }
262 };
263
264 static 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
273 module_platform_driver(mdio_gpio_driver);
274
275 MODULE_ALIAS("platform:mdio-gpio");
276 MODULE_AUTHOR("Laurent Pinchart, Paulius Zaleckas");
277 MODULE_LICENSE("GPL");
278 MODULE_DESCRIPTION("Generic driver for MDIO bus emulation using GPIO");
279