drivers/net/phy/mdio-gpio.c

   1 /*
   2  * GPIO based MDIO bitbang driver.
   3  * Supports OpenFirmware.
   4  *
   5  * Copyright (c) 2008 CSE Semaphore Belgium.
   6  *  by Laurent Pinchart <laurentp@cse-semaphore.com>
   7  *
   8  * Copyright (C) 2008, Paulius Zaleckas <paulius.zaleckas@teltonika.lt>
   9  *
  10  * Based on earlier work by
  11  *
  12  * Copyright (c) 2003 Intracom S.A.
  13  *  by Pantelis Antoniou <panto@intracom.gr>
  14  *
  15  * 2005 (c) MontaVista Software, Inc.
  16  * Vitaly Bordug <vbordug@ru.mvista.com>
  17  *
  18  * This file is licensed under the terms of the GNU General Public License
  19  * version 2. This program is licensed "as is" without any warranty of any
  20  * kind, whether express or implied.
  21  */
  22
  23 #include <linux/module.h>
  24 #include <linux/slab.h>
  25 #include <linux/interrupt.h>
  26 #include <linux/platform_device.h>
  27 #include <linux/mdio-bitbang.h>
  28 #include <linux/mdio-gpio.h>
  29 #include <linux/gpio/consumer.h>
  30 #include <linux/of_mdio.h>
  31
  32 struct mdio_gpio_info {
  33         struct mdiobb_ctrl ctrl;
  34         struct gpio_desc *mdc, *mdio, *mdo;
  35 };
  36
  37 static int mdio_gpio_get_data(struct device *dev,
  38                               struct mdio_gpio_info *bitbang)
  39 {
  40         bitbang->mdc = devm_gpiod_get_index(dev, NULL, MDIO_GPIO_MDC,
  41                                             GPIOD_OUT_LOW);
  42         if (IS_ERR(bitbang->mdc))
  43                 return PTR_ERR(bitbang->mdc);
  44
  45         bitbang->mdio = devm_gpiod_get_index(dev, NULL, MDIO_GPIO_MDIO,
  46                                              GPIOD_IN);
  47         if (IS_ERR(bitbang->mdio))
  48                 return PTR_ERR(bitbang->mdio);
  49
  50         bitbang->mdo = devm_gpiod_get_index_optional(dev, NULL, MDIO_GPIO_MDO,
  51                                                      GPIOD_OUT_LOW);
  52         return PTR_ERR_OR_ZERO(bitbang->mdo);
  53 }
  54
  55 static void mdio_dir(struct mdiobb_ctrl *ctrl, int dir)
  56 {
  57         struct mdio_gpio_info *bitbang =
  58                 container_of(ctrl, struct mdio_gpio_info, ctrl);
  59
  60         if (bitbang->mdo) {
  61                 /* Separate output pin. Always set its value to high
  62                  * when changing direction. If direction is input,
  63                  * assume the pin serves as pull-up. If direction is
  64                  * output, the default value is high.
  65                  */
  66                 gpiod_set_value_cansleep(bitbang->mdo, 1);
  67                 return;
  68         }
  69
  70         if (dir)
  71                 gpiod_direction_output(bitbang->mdio, 1);
  72         else
  73                 gpiod_direction_input(bitbang->mdio);
  74 }
  75
  76 static int mdio_get(struct mdiobb_ctrl *ctrl)
  77 {
  78         struct mdio_gpio_info *bitbang =
  79                 container_of(ctrl, struct mdio_gpio_info, ctrl);
  80
  81         return gpiod_get_value_cansleep(bitbang->mdio);
  82 }
  83
  84 static void mdio_set(struct mdiobb_ctrl *ctrl, int what)
  85 {
  86         struct mdio_gpio_info *bitbang =
  87                 container_of(ctrl, struct mdio_gpio_info, ctrl);
  88
  89         if (bitbang->mdo)
  90                 gpiod_set_value_cansleep(bitbang->mdo, what);
  91         else
  92                 gpiod_set_value_cansleep(bitbang->mdio, what);
  93 }
  94
  95 static void mdc_set(struct mdiobb_ctrl *ctrl, int what)
  96 {
  97         struct mdio_gpio_info *bitbang =
  98                 container_of(ctrl, struct mdio_gpio_info, ctrl);
  99
 100         gpiod_set_value_cansleep(bitbang->mdc, what);
 101 }
 102
 103 static const struct mdiobb_ops mdio_gpio_ops = {
 104         .owner = THIS_MODULE,
 105         .set_mdc = mdc_set,
 106         .set_mdio_dir = mdio_dir,
 107         .set_mdio_data = mdio_set,
 108         .get_mdio_data = mdio_get,
 109 };
 110
 111 static struct mii_bus *mdio_gpio_bus_init(struct device *dev,
 112                                           struct mdio_gpio_info *bitbang,
 113                                           int bus_id)
 114 {
 115         struct mii_bus *new_bus;
 116
 117         bitbang->ctrl.ops = &mdio_gpio_ops;
 118
 119         new_bus = alloc_mdio_bitbang(&bitbang->ctrl);
 120         if (!new_bus)
 121                 return NULL;
 122
 123         new_bus->name = "GPIO Bitbanged MDIO";
 124         new_bus->parent = dev;
 125
 126         if (bus_id != -1)
 127                 snprintf(new_bus->id, MII_BUS_ID_SIZE, "gpio-%x", bus_id);
 128         else
 129                 strncpy(new_bus->id, "gpio", MII_BUS_ID_SIZE);
 130
 131         dev_set_drvdata(dev, new_bus);
 132
 133         return new_bus;
 134 }
 135
 136 static void mdio_gpio_bus_deinit(struct device *dev)
 137 {
 138         struct mii_bus *bus = dev_get_drvdata(dev);
 139
 140         free_mdio_bitbang(bus);
 141 }
 142
 143 static void mdio_gpio_bus_destroy(struct device *dev)
 144 {
 145         struct mii_bus *bus = dev_get_drvdata(dev);
 146
 147         mdiobus_unregister(bus);
 148         mdio_gpio_bus_deinit(dev);
 149 }
 150
 151 static int mdio_gpio_probe(struct platform_device *pdev)
 152 {
 153         struct mdio_gpio_info *bitbang;
 154         struct mii_bus *new_bus;
 155         int ret, bus_id;
 156
 157         bitbang = devm_kzalloc(&pdev->dev, sizeof(*bitbang), GFP_KERNEL);
 158         if (!bitbang)
 159                 return -ENOMEM;
 160
 161         ret = mdio_gpio_get_data(&pdev->dev, bitbang);
 162         if (ret)
 163                 return ret;
 164
 165         if (pdev->dev.of_node) {
 166                 bus_id = of_alias_get_id(pdev->dev.of_node, "mdio-gpio");
 167                 if (bus_id < 0) {
 168                         dev_warn(&pdev->dev, "failed to get alias id\n");
 169                         bus_id = 0;
 170                 }
 171         } else {
 172                 bus_id = pdev->id;
 173         }
 174
 175         new_bus = mdio_gpio_bus_init(&pdev->dev, bitbang, bus_id);
 176         if (!new_bus)
 177                 return -ENODEV;
 178
 179         ret = of_mdiobus_register(new_bus, pdev->dev.of_node);
 180         if (ret)
 181                 mdio_gpio_bus_deinit(&pdev->dev);
 182
 183         return ret;
 184 }
 185
 186 static int mdio_gpio_remove(struct platform_device *pdev)
 187 {
 188         mdio_gpio_bus_destroy(&pdev->dev);
 189
 190         return 0;
 191 }
 192
 193 static const struct of_device_id mdio_gpio_of_match[] = {
 194         { .compatible = "virtual,mdio-gpio", },
 195         { /* sentinel */ }
 196 };
 197 MODULE_DEVICE_TABLE(of, mdio_gpio_of_match);
 198
 199 static struct platform_driver mdio_gpio_driver = {
 200         .probe = mdio_gpio_probe,
 201         .remove = mdio_gpio_remove,
 202         .driver         = {
 203                 .name   = "mdio-gpio",
 204                 .of_match_table = mdio_gpio_of_match,
 205         },
 206 };
 207
 208 module_platform_driver(mdio_gpio_driver);
 209
 210 MODULE_ALIAS("platform:mdio-gpio");
 211 MODULE_AUTHOR("Laurent Pinchart, Paulius Zaleckas");
 212 MODULE_LICENSE("GPL");
 213 MODULE_DESCRIPTION("Generic driver for MDIO bus emulation using GPIO");