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1// SPDX-License-Identifier: GPL-2.02/*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 by12 *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 30struct mdio_gpio_info {31 struct mdiobb_ctrl ctrl;32 struct gpio_desc *mdc, *mdio, *mdo;33};34 35static 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 53static 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 high60 * when changing direction. If direction is input,61 * assume the pin serves as pull-up. If direction is62 * 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 else71 gpiod_direction_input(bitbang->mdio);72}73 74static 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 82static 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 else90 gpiod_set_value_cansleep(bitbang->mdio, what);91}92 93static 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 101static 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 109static 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, sizeof(new_bus->id), "gpio-%x", bus_id);127 else128 strscpy(new_bus->id, "gpio", sizeof(new_bus->id));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 (device_is_compatible(dev, "microchip,mdio-smi0")) {136 bitbang->ctrl.op_c22_read = 0;137 bitbang->ctrl.op_c22_write = 0;138 bitbang->ctrl.override_op_c22 = 1;139 }140 141 dev_set_drvdata(dev, new_bus);142 143 return new_bus;144}145 146static void mdio_gpio_bus_deinit(struct device *dev)147{148 struct mii_bus *bus = dev_get_drvdata(dev);149 150 free_mdio_bitbang(bus);151}152 153static void mdio_gpio_bus_destroy(struct device *dev)154{155 struct mii_bus *bus = dev_get_drvdata(dev);156 157 mdiobus_unregister(bus);158 mdio_gpio_bus_deinit(dev);159}160 161static int mdio_gpio_probe(struct platform_device *pdev)162{163 struct mdio_gpio_info *bitbang;164 struct mii_bus *new_bus;165 int ret, bus_id;166 167 bitbang = devm_kzalloc(&pdev->dev, sizeof(*bitbang), GFP_KERNEL);168 if (!bitbang)169 return -ENOMEM;170 171 ret = mdio_gpio_get_data(&pdev->dev, bitbang);172 if (ret)173 return ret;174 175 if (pdev->dev.of_node) {176 bus_id = of_alias_get_id(pdev->dev.of_node, "mdio-gpio");177 if (bus_id < 0) {178 dev_warn(&pdev->dev, "failed to get alias id\n");179 bus_id = 0;180 }181 } else {182 bus_id = pdev->id;183 }184 185 new_bus = mdio_gpio_bus_init(&pdev->dev, bitbang, bus_id);186 if (!new_bus)187 return -ENODEV;188 189 ret = of_mdiobus_register(new_bus, pdev->dev.of_node);190 if (ret)191 mdio_gpio_bus_deinit(&pdev->dev);192 193 return ret;194}195 196static void mdio_gpio_remove(struct platform_device *pdev)197{198 mdio_gpio_bus_destroy(&pdev->dev);199}200 201static const struct of_device_id mdio_gpio_of_match[] = {202 { .compatible = "virtual,mdio-gpio", },203 { .compatible = "microchip,mdio-smi0" },204 { /* sentinel */ }205};206MODULE_DEVICE_TABLE(of, mdio_gpio_of_match);207 208static struct platform_driver mdio_gpio_driver = {209 .probe = mdio_gpio_probe,210 .remove_new = mdio_gpio_remove,211 .driver = {212 .name = "mdio-gpio",213 .of_match_table = mdio_gpio_of_match,214 },215};216 217module_platform_driver(mdio_gpio_driver);218 219MODULE_ALIAS("platform:mdio-gpio");220MODULE_AUTHOR("Laurent Pinchart, Paulius Zaleckas");221MODULE_LICENSE("GPL v2");222MODULE_DESCRIPTION("Generic driver for MDIO bus emulation using GPIO");223