net/mdio/mdio-gpio.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * GPIO based MDIO bitbang driver.
0004  * Supports OpenFirmware.
0005  *
0006  * Copyright (c) 2008 CSE Semaphore Belgium.
0007  *  by Laurent Pinchart <laurentp@cse-semaphore.com>
0008  *
0009  * Copyright (C) 2008, Paulius Zaleckas <paulius.zaleckas@teltonika.lt>
0010  *
0011  * Based on earlier work by
0012  *
0013  * Copyright (c) 2003 Intracom S.A.
0014  *  by Pantelis Antoniou <panto@intracom.gr>
0015  *
0016  * 2005 (c) MontaVista Software, Inc.
0017  * Vitaly Bordug <vbordug@ru.mvista.com>
0018  */
0019
0020 #include <linux/gpio/consumer.h>
0021 #include <linux/interrupt.h>
0022 #include <linux/mdio-bitbang.h>
0023 #include <linux/mdio-gpio.h>
0024 #include <linux/module.h>
0025 #include <linux/of_mdio.h>
0026 #include <linux/platform_data/mdio-gpio.h>
0027 #include <linux/platform_device.h>
0028 #include <linux/slab.h>
0029
0030 struct mdio_gpio_info {
0031     struct mdiobb_ctrl ctrl;
0032     struct gpio_desc *mdc, *mdio, *mdo;
0033 };
0034
0035 static int mdio_gpio_get_data(struct device *dev,
0036                   struct mdio_gpio_info *bitbang)
0037 {
0038     bitbang->mdc = devm_gpiod_get_index(dev, NULL, MDIO_GPIO_MDC,
0039                         GPIOD_OUT_LOW);
0040     if (IS_ERR(bitbang->mdc))
0041         return PTR_ERR(bitbang->mdc);
0042
0043     bitbang->mdio = devm_gpiod_get_index(dev, NULL, MDIO_GPIO_MDIO,
0044                          GPIOD_IN);
0045     if (IS_ERR(bitbang->mdio))
0046         return PTR_ERR(bitbang->mdio);
0047
0048     bitbang->mdo = devm_gpiod_get_index_optional(dev, NULL, MDIO_GPIO_MDO,
0049                              GPIOD_OUT_LOW);
0050     return PTR_ERR_OR_ZERO(bitbang->mdo);
0051 }
0052
0053 static void mdio_dir(struct mdiobb_ctrl *ctrl, int dir)
0054 {
0055     struct mdio_gpio_info *bitbang =
0056         container_of(ctrl, struct mdio_gpio_info, ctrl);
0057
0058     if (bitbang->mdo) {
0059         /* Separate output pin. Always set its value to high
0060          * when changing direction. If direction is input,
0061          * assume the pin serves as pull-up. If direction is
0062          * output, the default value is high.
0063          */
0064         gpiod_set_value_cansleep(bitbang->mdo, 1);
0065         return;
0066     }
0067
0068     if (dir)
0069         gpiod_direction_output(bitbang->mdio, 1);
0070     else
0071         gpiod_direction_input(bitbang->mdio);
0072 }
0073
0074 static int mdio_get(struct mdiobb_ctrl *ctrl)
0075 {
0076     struct mdio_gpio_info *bitbang =
0077         container_of(ctrl, struct mdio_gpio_info, ctrl);
0078
0079     return gpiod_get_value_cansleep(bitbang->mdio);
0080 }
0081
0082 static void mdio_set(struct mdiobb_ctrl *ctrl, int what)
0083 {
0084     struct mdio_gpio_info *bitbang =
0085         container_of(ctrl, struct mdio_gpio_info, ctrl);
0086
0087     if (bitbang->mdo)
0088         gpiod_set_value_cansleep(bitbang->mdo, what);
0089     else
0090         gpiod_set_value_cansleep(bitbang->mdio, what);
0091 }
0092
0093 static void mdc_set(struct mdiobb_ctrl *ctrl, int what)
0094 {
0095     struct mdio_gpio_info *bitbang =
0096         container_of(ctrl, struct mdio_gpio_info, ctrl);
0097
0098     gpiod_set_value_cansleep(bitbang->mdc, what);
0099 }
0100
0101 static const struct mdiobb_ops mdio_gpio_ops = {
0102     .owner = THIS_MODULE,
0103     .set_mdc = mdc_set,
0104     .set_mdio_dir = mdio_dir,
0105     .set_mdio_data = mdio_set,
0106     .get_mdio_data = mdio_get,
0107 };
0108
0109 static struct mii_bus *mdio_gpio_bus_init(struct device *dev,
0110                       struct mdio_gpio_info *bitbang,
0111                       int bus_id)
0112 {
0113     struct mdio_gpio_platform_data *pdata = dev_get_platdata(dev);
0114     struct mii_bus *new_bus;
0115
0116     bitbang->ctrl.ops = &mdio_gpio_ops;
0117
0118     new_bus = alloc_mdio_bitbang(&bitbang->ctrl);
0119     if (!new_bus)
0120         return NULL;
0121
0122     new_bus->name = "GPIO Bitbanged MDIO";
0123     new_bus->parent = dev;
0124
0125     if (bus_id != -1)
0126         snprintf(new_bus->id, MII_BUS_ID_SIZE, "gpio-%x", bus_id);
0127     else
0128         strncpy(new_bus->id, "gpio", MII_BUS_ID_SIZE);
0129
0130     if (pdata) {
0131         new_bus->phy_mask = pdata->phy_mask;
0132         new_bus->phy_ignore_ta_mask = pdata->phy_ignore_ta_mask;
0133     }
0134
0135     if (dev->of_node &&
0136         of_device_is_compatible(dev->of_node, "microchip,mdio-smi0")) {
0137         bitbang->ctrl.op_c22_read = 0;
0138         bitbang->ctrl.op_c22_write = 0;
0139         bitbang->ctrl.override_op_c22 = 1;
0140     }
0141
0142     dev_set_drvdata(dev, new_bus);
0143
0144     return new_bus;
0145 }
0146
0147 static void mdio_gpio_bus_deinit(struct device *dev)
0148 {
0149     struct mii_bus *bus = dev_get_drvdata(dev);
0150
0151     free_mdio_bitbang(bus);
0152 }
0153
0154 static void mdio_gpio_bus_destroy(struct device *dev)
0155 {
0156     struct mii_bus *bus = dev_get_drvdata(dev);
0157
0158     mdiobus_unregister(bus);
0159     mdio_gpio_bus_deinit(dev);
0160 }
0161
0162 static int mdio_gpio_probe(struct platform_device *pdev)
0163 {
0164     struct mdio_gpio_info *bitbang;
0165     struct mii_bus *new_bus;
0166     int ret, bus_id;
0167
0168     bitbang = devm_kzalloc(&pdev->dev, sizeof(*bitbang), GFP_KERNEL);
0169     if (!bitbang)
0170         return -ENOMEM;
0171
0172     ret = mdio_gpio_get_data(&pdev->dev, bitbang);
0173     if (ret)
0174         return ret;
0175
0176     if (pdev->dev.of_node) {
0177         bus_id = of_alias_get_id(pdev->dev.of_node, "mdio-gpio");
0178         if (bus_id < 0) {
0179             dev_warn(&pdev->dev, "failed to get alias id\n");
0180             bus_id = 0;
0181         }
0182     } else {
0183         bus_id = pdev->id;
0184     }
0185
0186     new_bus = mdio_gpio_bus_init(&pdev->dev, bitbang, bus_id);
0187     if (!new_bus)
0188         return -ENODEV;
0189
0190     ret = of_mdiobus_register(new_bus, pdev->dev.of_node);
0191     if (ret)
0192         mdio_gpio_bus_deinit(&pdev->dev);
0193
0194     return ret;
0195 }
0196
0197 static int mdio_gpio_remove(struct platform_device *pdev)
0198 {
0199     mdio_gpio_bus_destroy(&pdev->dev);
0200
0201     return 0;
0202 }
0203
0204 static const struct of_device_id mdio_gpio_of_match[] = {
0205     { .compatible = "virtual,mdio-gpio", },
0206     { .compatible = "microchip,mdio-smi0" },
0207     { /* sentinel */ }
0208 };
0209 MODULE_DEVICE_TABLE(of, mdio_gpio_of_match);
0210
0211 static struct platform_driver mdio_gpio_driver = {
0212     .probe = mdio_gpio_probe,
0213     .remove = mdio_gpio_remove,
0214     .driver     = {
0215         .name   = "mdio-gpio",
0216         .of_match_table = mdio_gpio_of_match,
0217     },
0218 };
0219
0220 module_platform_driver(mdio_gpio_driver);
0221
0222 MODULE_ALIAS("platform:mdio-gpio");
0223 MODULE_AUTHOR("Laurent Pinchart, Paulius Zaleckas");
0224 MODULE_LICENSE("GPL v2");
0225 MODULE_DESCRIPTION("Generic driver for MDIO bus emulation using GPIO");