xref: /openbmc/linux/drivers/net/mdio/mdio-gpio.c (revision 800fcab8)
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