1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * GPIO based MDIO bitbang driver.
4 * Supports OpenFirmware.
5 *
6 * Copyright (c) 2008 CSE Semaphore Belgium.
7 * by Laurent Pinchart <laurentp@cse-semaphore.com>
8 *
9 * Copyright (C) 2008, Paulius Zaleckas <paulius.zaleckas@teltonika.lt>
10 *
11 * Based on earlier work by
12 *
13 * Copyright (c) 2003 Intracom S.A.
14 * by Pantelis Antoniou <panto@intracom.gr>
15 *
16 * 2005 (c) MontaVista Software, Inc.
17 * Vitaly Bordug <vbordug@ru.mvista.com>
18 */
19
20 #include <linux/gpio/consumer.h>
21 #include <linux/interrupt.h>
22 #include <linux/mdio-bitbang.h>
23 #include <linux/mdio-gpio.h>
24 #include <linux/module.h>
25 #include <linux/of_mdio.h>
26 #include <linux/platform_data/mdio-gpio.h>
27 #include <linux/platform_device.h>
28 #include <linux/slab.h>
29
30 struct mdio_gpio_info {
31 struct mdiobb_ctrl ctrl;
32 struct gpio_desc *mdc, *mdio, *mdo;
33 };
34
mdio_gpio_get_data(struct device * dev,struct mdio_gpio_info * bitbang)35 static int mdio_gpio_get_data(struct device *dev,
36 struct mdio_gpio_info *bitbang)
37 {
38 bitbang->mdc = devm_gpiod_get_index(dev, NULL, MDIO_GPIO_MDC,
39 GPIOD_OUT_LOW);
40 if (IS_ERR(bitbang->mdc))
41 return PTR_ERR(bitbang->mdc);
42
43 bitbang->mdio = devm_gpiod_get_index(dev, NULL, MDIO_GPIO_MDIO,
44 GPIOD_IN);
45 if (IS_ERR(bitbang->mdio))
46 return PTR_ERR(bitbang->mdio);
47
48 bitbang->mdo = devm_gpiod_get_index_optional(dev, NULL, MDIO_GPIO_MDO,
49 GPIOD_OUT_LOW);
50 return PTR_ERR_OR_ZERO(bitbang->mdo);
51 }
52
mdio_dir(struct mdiobb_ctrl * ctrl,int dir)53 static void mdio_dir(struct mdiobb_ctrl *ctrl, int dir)
54 {
55 struct mdio_gpio_info *bitbang =
56 container_of(ctrl, struct mdio_gpio_info, ctrl);
57
58 if (bitbang->mdo) {
59 /* Separate output pin. Always set its value to high
60 * when changing direction. If direction is input,
61 * assume the pin serves as pull-up. If direction is
62 * output, the default value is high.
63 */
64 gpiod_set_value_cansleep(bitbang->mdo, 1);
65 return;
66 }
67
68 if (dir)
69 gpiod_direction_output(bitbang->mdio, 1);
70 else
71 gpiod_direction_input(bitbang->mdio);
72 }
73
mdio_get(struct mdiobb_ctrl * ctrl)74 static int mdio_get(struct mdiobb_ctrl *ctrl)
75 {
76 struct mdio_gpio_info *bitbang =
77 container_of(ctrl, struct mdio_gpio_info, ctrl);
78
79 return gpiod_get_value_cansleep(bitbang->mdio);
80 }
81
mdio_set(struct mdiobb_ctrl * ctrl,int what)82 static void mdio_set(struct mdiobb_ctrl *ctrl, int what)
83 {
84 struct mdio_gpio_info *bitbang =
85 container_of(ctrl, struct mdio_gpio_info, ctrl);
86
87 if (bitbang->mdo)
88 gpiod_set_value_cansleep(bitbang->mdo, what);
89 else
90 gpiod_set_value_cansleep(bitbang->mdio, what);
91 }
92
mdc_set(struct mdiobb_ctrl * ctrl,int what)93 static void mdc_set(struct mdiobb_ctrl *ctrl, int what)
94 {
95 struct mdio_gpio_info *bitbang =
96 container_of(ctrl, struct mdio_gpio_info, ctrl);
97
98 gpiod_set_value_cansleep(bitbang->mdc, what);
99 }
100
101 static const struct mdiobb_ops mdio_gpio_ops = {
102 .owner = THIS_MODULE,
103 .set_mdc = mdc_set,
104 .set_mdio_dir = mdio_dir,
105 .set_mdio_data = mdio_set,
106 .get_mdio_data = mdio_get,
107 };
108
mdio_gpio_bus_init(struct device * dev,struct mdio_gpio_info * bitbang,int bus_id)109 static struct mii_bus *mdio_gpio_bus_init(struct device *dev,
110 struct mdio_gpio_info *bitbang,
111 int bus_id)
112 {
113 struct mdio_gpio_platform_data *pdata = dev_get_platdata(dev);
114 struct mii_bus *new_bus;
115
116 bitbang->ctrl.ops = &mdio_gpio_ops;
117
118 new_bus = alloc_mdio_bitbang(&bitbang->ctrl);
119 if (!new_bus)
120 return NULL;
121
122 new_bus->name = "GPIO Bitbanged MDIO";
123 new_bus->parent = dev;
124
125 if (bus_id != -1)
126 snprintf(new_bus->id, MII_BUS_ID_SIZE, "gpio-%x", bus_id);
127 else
128 strncpy(new_bus->id, "gpio", MII_BUS_ID_SIZE);
129
130 if (pdata) {
131 new_bus->phy_mask = pdata->phy_mask;
132 new_bus->phy_ignore_ta_mask = pdata->phy_ignore_ta_mask;
133 }
134
135 if (dev->of_node &&
136 of_device_is_compatible(dev->of_node, "microchip,mdio-smi0")) {
137 bitbang->ctrl.op_c22_read = 0;
138 bitbang->ctrl.op_c22_write = 0;
139 bitbang->ctrl.override_op_c22 = 1;
140 }
141
142 dev_set_drvdata(dev, new_bus);
143
144 return new_bus;
145 }
146
mdio_gpio_bus_deinit(struct device * dev)147 static void mdio_gpio_bus_deinit(struct device *dev)
148 {
149 struct mii_bus *bus = dev_get_drvdata(dev);
150
151 free_mdio_bitbang(bus);
152 }
153
mdio_gpio_bus_destroy(struct device * dev)154 static void mdio_gpio_bus_destroy(struct device *dev)
155 {
156 struct mii_bus *bus = dev_get_drvdata(dev);
157
158 mdiobus_unregister(bus);
159 mdio_gpio_bus_deinit(dev);
160 }
161
mdio_gpio_probe(struct platform_device * pdev)162 static int mdio_gpio_probe(struct platform_device *pdev)
163 {
164 struct mdio_gpio_info *bitbang;
165 struct mii_bus *new_bus;
166 int ret, bus_id;
167
168 bitbang = devm_kzalloc(&pdev->dev, sizeof(*bitbang), GFP_KERNEL);
169 if (!bitbang)
170 return -ENOMEM;
171
172 ret = mdio_gpio_get_data(&pdev->dev, bitbang);
173 if (ret)
174 return ret;
175
176 if (pdev->dev.of_node) {
177 bus_id = of_alias_get_id(pdev->dev.of_node, "mdio-gpio");
178 if (bus_id < 0) {
179 dev_warn(&pdev->dev, "failed to get alias id\n");
180 bus_id = 0;
181 }
182 } else {
183 bus_id = pdev->id;
184 }
185
186 new_bus = mdio_gpio_bus_init(&pdev->dev, bitbang, bus_id);
187 if (!new_bus)
188 return -ENODEV;
189
190 ret = of_mdiobus_register(new_bus, pdev->dev.of_node);
191 if (ret)
192 mdio_gpio_bus_deinit(&pdev->dev);
193
194 return ret;
195 }
196
mdio_gpio_remove(struct platform_device * pdev)197 static int mdio_gpio_remove(struct platform_device *pdev)
198 {
199 mdio_gpio_bus_destroy(&pdev->dev);
200
201 return 0;
202 }
203
204 static const struct of_device_id mdio_gpio_of_match[] = {
205 { .compatible = "virtual,mdio-gpio", },
206 { .compatible = "microchip,mdio-smi0" },
207 { /* sentinel */ }
208 };
209 MODULE_DEVICE_TABLE(of, mdio_gpio_of_match);
210
211 static struct platform_driver mdio_gpio_driver = {
212 .probe = mdio_gpio_probe,
213 .remove = mdio_gpio_remove,
214 .driver = {
215 .name = "mdio-gpio",
216 .of_match_table = mdio_gpio_of_match,
217 },
218 };
219
220 module_platform_driver(mdio_gpio_driver);
221
222 MODULE_ALIAS("platform:mdio-gpio");
223 MODULE_AUTHOR("Laurent Pinchart, Paulius Zaleckas");
224 MODULE_LICENSE("GPL v2");
225 MODULE_DESCRIPTION("Generic driver for MDIO bus emulation using GPIO");
226