1 // SPDX-License-Identifier: GPL-2.0
3 * GPIO based MDIO bitbang driver.
4 * Supports OpenFirmware.
6 * Copyright (c) 2008 CSE Semaphore Belgium.
7 * by Laurent Pinchart <laurentp@cse-semaphore.com>
9 * Copyright (C) 2008, Paulius Zaleckas <paulius.zaleckas@teltonika.lt>
11 * Based on earlier work by
13 * Copyright (c) 2003 Intracom S.A.
14 * by Pantelis Antoniou <panto@intracom.gr>
16 * 2005 (c) MontaVista Software, Inc.
17 * Vitaly Bordug <vbordug@ru.mvista.com>
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>
30 struct mdio_gpio_info {
31 struct mdiobb_ctrl ctrl;
32 struct gpio_desc *mdc, *mdio, *mdo;
35 static int mdio_gpio_get_data(struct device *dev,
36 struct mdio_gpio_info *bitbang)
38 bitbang->mdc = devm_gpiod_get_index(dev, NULL, MDIO_GPIO_MDC,
40 if (IS_ERR(bitbang->mdc))
41 return PTR_ERR(bitbang->mdc);
43 bitbang->mdio = devm_gpiod_get_index(dev, NULL, MDIO_GPIO_MDIO,
45 if (IS_ERR(bitbang->mdio))
46 return PTR_ERR(bitbang->mdio);
48 bitbang->mdo = devm_gpiod_get_index_optional(dev, NULL, MDIO_GPIO_MDO,
50 return PTR_ERR_OR_ZERO(bitbang->mdo);
53 static void mdio_dir(struct mdiobb_ctrl *ctrl, int dir)
55 struct mdio_gpio_info *bitbang =
56 container_of(ctrl, struct mdio_gpio_info, ctrl);
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.
64 gpiod_set_value_cansleep(bitbang->mdo, 1);
69 gpiod_direction_output(bitbang->mdio, 1);
71 gpiod_direction_input(bitbang->mdio);
74 static int mdio_get(struct mdiobb_ctrl *ctrl)
76 struct mdio_gpio_info *bitbang =
77 container_of(ctrl, struct mdio_gpio_info, ctrl);
79 return gpiod_get_value_cansleep(bitbang->mdio);
82 static void mdio_set(struct mdiobb_ctrl *ctrl, int what)
84 struct mdio_gpio_info *bitbang =
85 container_of(ctrl, struct mdio_gpio_info, ctrl);
88 gpiod_set_value_cansleep(bitbang->mdo, what);
90 gpiod_set_value_cansleep(bitbang->mdio, what);
93 static void mdc_set(struct mdiobb_ctrl *ctrl, int what)
95 struct mdio_gpio_info *bitbang =
96 container_of(ctrl, struct mdio_gpio_info, ctrl);
98 gpiod_set_value_cansleep(bitbang->mdc, what);
101 static const struct mdiobb_ops mdio_gpio_ops = {
102 .owner = THIS_MODULE,
104 .set_mdio_dir = mdio_dir,
105 .set_mdio_data = mdio_set,
106 .get_mdio_data = mdio_get,
109 static struct mii_bus *mdio_gpio_bus_init(struct device *dev,
110 struct mdio_gpio_info *bitbang,
113 struct mdio_gpio_platform_data *pdata = dev_get_platdata(dev);
114 struct mii_bus *new_bus;
116 bitbang->ctrl.ops = &mdio_gpio_ops;
118 new_bus = alloc_mdio_bitbang(&bitbang->ctrl);
122 new_bus->name = "GPIO Bitbanged MDIO";
123 new_bus->parent = dev;
126 snprintf(new_bus->id, MII_BUS_ID_SIZE, "gpio-%x", bus_id);
128 strncpy(new_bus->id, "gpio", MII_BUS_ID_SIZE);
131 new_bus->phy_mask = pdata->phy_mask;
132 new_bus->phy_ignore_ta_mask = pdata->phy_ignore_ta_mask;
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;
142 dev_set_drvdata(dev, new_bus);
147 static void mdio_gpio_bus_deinit(struct device *dev)
149 struct mii_bus *bus = dev_get_drvdata(dev);
151 free_mdio_bitbang(bus);
154 static void mdio_gpio_bus_destroy(struct device *dev)
156 struct mii_bus *bus = dev_get_drvdata(dev);
158 mdiobus_unregister(bus);
159 mdio_gpio_bus_deinit(dev);
162 static int mdio_gpio_probe(struct platform_device *pdev)
164 struct mdio_gpio_info *bitbang;
165 struct mii_bus *new_bus;
168 bitbang = devm_kzalloc(&pdev->dev, sizeof(*bitbang), GFP_KERNEL);
172 ret = mdio_gpio_get_data(&pdev->dev, bitbang);
176 if (pdev->dev.of_node) {
177 bus_id = of_alias_get_id(pdev->dev.of_node, "mdio-gpio");
179 dev_warn(&pdev->dev, "failed to get alias id\n");
186 new_bus = mdio_gpio_bus_init(&pdev->dev, bitbang, bus_id);
190 ret = of_mdiobus_register(new_bus, pdev->dev.of_node);
192 mdio_gpio_bus_deinit(&pdev->dev);
197 static int mdio_gpio_remove(struct platform_device *pdev)
199 mdio_gpio_bus_destroy(&pdev->dev);
204 static const struct of_device_id mdio_gpio_of_match[] = {
205 { .compatible = "virtual,mdio-gpio", },
206 { .compatible = "microchip,mdio-smi0" },
209 MODULE_DEVICE_TABLE(of, mdio_gpio_of_match);
211 static struct platform_driver mdio_gpio_driver = {
212 .probe = mdio_gpio_probe,
213 .remove = mdio_gpio_remove,
216 .of_match_table = mdio_gpio_of_match,
220 module_platform_driver(mdio_gpio_driver);
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");