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/gpio.h>
  28 #include <linux/platform_data/mdio-gpio.h>
  29
  30 #include <linux/of_gpio.h>
  31 #include <linux/of_mdio.h>
  32
  33 struct mdio_gpio_info {
  34         struct mdiobb_ctrl ctrl;
  35         struct gpio_desc *mdc, *mdio, *mdo;
  36 };
  37
  38 static void *mdio_gpio_of_get_data(struct platform_device *pdev)
  39 {
  40         struct device_node *np = pdev->dev.of_node;
  41         struct mdio_gpio_platform_data *pdata;
  42         enum of_gpio_flags flags;
  43         int ret;
  44
  45         pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
  46         if (!pdata)
  47                 return NULL;
  48
  49         ret = of_get_gpio_flags(np, 0, &flags);
  50         if (ret < 0)
  51                 return NULL;
  52
  53         pdata->mdc = ret;
  54         pdata->mdc_active_low = flags & OF_GPIO_ACTIVE_LOW;
  55
  56         ret = of_get_gpio_flags(np, 1, &flags);
  57         if (ret < 0)
  58                 return NULL;
  59         pdata->mdio = ret;
  60         pdata->mdio_active_low = flags & OF_GPIO_ACTIVE_LOW;
  61
  62         ret = of_get_gpio_flags(np, 2, &flags);
  63         if (ret > 0) {
  64                 pdata->mdo = ret;
  65                 pdata->mdo_active_low = flags & OF_GPIO_ACTIVE_LOW;
  66         }
  67
  68         return pdata;
  69 }
  70
  71 static void mdio_dir(struct mdiobb_ctrl *ctrl, int dir)
  72 {
  73         struct mdio_gpio_info *bitbang =
  74                 container_of(ctrl, struct mdio_gpio_info, ctrl);
  75
  76         if (bitbang->mdo) {
  77                 /* Separate output pin. Always set its value to high
  78                  * when changing direction. If direction is input,
  79                  * assume the pin serves as pull-up. If direction is
  80                  * output, the default value is high.
  81                  */
  82                 gpiod_set_value(bitbang->mdo, 1);
  83                 return;
  84         }
  85
  86         if (dir)
  87                 gpiod_direction_output(bitbang->mdio, 1);
  88         else
  89                 gpiod_direction_input(bitbang->mdio);
  90 }
  91
  92 static int mdio_get(struct mdiobb_ctrl *ctrl)
  93 {
  94         struct mdio_gpio_info *bitbang =
  95                 container_of(ctrl, struct mdio_gpio_info, ctrl);
  96
  97         return gpiod_get_value(bitbang->mdio);
  98 }
  99
 100 static void mdio_set(struct mdiobb_ctrl *ctrl, int what)
 101 {
 102         struct mdio_gpio_info *bitbang =
 103                 container_of(ctrl, struct mdio_gpio_info, ctrl);
 104
 105         if (bitbang->mdo)
 106                 gpiod_set_value(bitbang->mdo, what);
 107         else
 108                 gpiod_set_value(bitbang->mdio, what);
 109 }
 110
 111 static void mdc_set(struct mdiobb_ctrl *ctrl, int what)
 112 {
 113         struct mdio_gpio_info *bitbang =
 114                 container_of(ctrl, struct mdio_gpio_info, ctrl);
 115
 116         gpiod_set_value(bitbang->mdc, what);
 117 }
 118
 119 static struct mdiobb_ops mdio_gpio_ops = {
 120         .owner = THIS_MODULE,
 121         .set_mdc = mdc_set,
 122         .set_mdio_dir = mdio_dir,
 123         .set_mdio_data = mdio_set,
 124         .get_mdio_data = mdio_get,
 125 };
 126
 127 static struct mii_bus *mdio_gpio_bus_init(struct device *dev,
 128                                           struct mdio_gpio_platform_data *pdata,
 129                                           int bus_id)
 130 {
 131         struct mii_bus *new_bus;
 132         struct mdio_gpio_info *bitbang;
 133         int i;
 134         int mdc, mdio, mdo;
 135         unsigned long mdc_flags = GPIOF_OUT_INIT_LOW;
 136         unsigned long mdio_flags = GPIOF_DIR_IN;
 137         unsigned long mdo_flags = GPIOF_OUT_INIT_HIGH;
 138
 139         bitbang = devm_kzalloc(dev, sizeof(*bitbang), GFP_KERNEL);
 140         if (!bitbang)
 141                 goto out;
 142
 143         bitbang->ctrl.ops = &mdio_gpio_ops;
 144         bitbang->ctrl.reset = pdata->reset;
 145         mdc = pdata->mdc;
 146         bitbang->mdc = gpio_to_desc(mdc);
 147         if (pdata->mdc_active_low)
 148                 mdc_flags = GPIOF_OUT_INIT_HIGH | GPIOF_ACTIVE_LOW;
 149         mdio = pdata->mdio;
 150         bitbang->mdio = gpio_to_desc(mdio);
 151         if (pdata->mdio_active_low)
 152                 mdio_flags |= GPIOF_ACTIVE_LOW;
 153         mdo = pdata->mdo;
 154         if (mdo) {
 155                 bitbang->mdo = gpio_to_desc(mdo);
 156                 if (pdata->mdo_active_low)
 157                         mdo_flags = GPIOF_OUT_INIT_LOW | GPIOF_ACTIVE_LOW;
 158         }
 159
 160         new_bus = alloc_mdio_bitbang(&bitbang->ctrl);
 161         if (!new_bus)
 162                 goto out;
 163
 164         new_bus->name = "GPIO Bitbanged MDIO",
 165
 166         new_bus->phy_mask = pdata->phy_mask;
 167         new_bus->phy_ignore_ta_mask = pdata->phy_ignore_ta_mask;
 168         memcpy(new_bus->irq, pdata->irqs, sizeof(new_bus->irq));
 169         new_bus->parent = dev;
 170
 171         if (new_bus->phy_mask == ~0)
 172                 goto out_free_bus;
 173
 174         for (i = 0; i < PHY_MAX_ADDR; i++)
 175                 if (!new_bus->irq[i])
 176                         new_bus->irq[i] = PHY_POLL;
 177
 178         if (bus_id != -1)
 179                 snprintf(new_bus->id, MII_BUS_ID_SIZE, "gpio-%x", bus_id);
 180         else
 181                 strncpy(new_bus->id, "gpio", MII_BUS_ID_SIZE);
 182
 183         if (devm_gpio_request_one(dev, mdc, mdc_flags, "mdc"))
 184                 goto out_free_bus;
 185
 186         if (devm_gpio_request_one(dev, mdio, mdio_flags, "mdio"))
 187                 goto out_free_bus;
 188
 189         if (mdo && devm_gpio_request_one(dev, mdo, mdo_flags, "mdo"))
 190                 goto out_free_bus;
 191
 192         dev_set_drvdata(dev, new_bus);
 193
 194         return new_bus;
 195
 196 out_free_bus:
 197         free_mdio_bitbang(new_bus);
 198 out:
 199         return NULL;
 200 }
 201
 202 static void mdio_gpio_bus_deinit(struct device *dev)
 203 {
 204         struct mii_bus *bus = dev_get_drvdata(dev);
 205
 206         free_mdio_bitbang(bus);
 207 }
 208
 209 static void mdio_gpio_bus_destroy(struct device *dev)
 210 {
 211         struct mii_bus *bus = dev_get_drvdata(dev);
 212
 213         mdiobus_unregister(bus);
 214         mdio_gpio_bus_deinit(dev);
 215 }
 216
 217 static int mdio_gpio_probe(struct platform_device *pdev)
 218 {
 219         struct mdio_gpio_platform_data *pdata;
 220         struct mii_bus *new_bus;
 221         int ret, bus_id;
 222
 223         if (pdev->dev.of_node) {
 224                 pdata = mdio_gpio_of_get_data(pdev);
 225                 bus_id = of_alias_get_id(pdev->dev.of_node, "mdio-gpio");
 226                 if (bus_id < 0) {
 227                         dev_warn(&pdev->dev, "failed to get alias id\n");
 228                         bus_id = 0;
 229                 }
 230         } else {
 231                 pdata = dev_get_platdata(&pdev->dev);
 232                 bus_id = pdev->id;
 233         }
 234
 235         if (!pdata)
 236                 return -ENODEV;
 237
 238         new_bus = mdio_gpio_bus_init(&pdev->dev, pdata, bus_id);
 239         if (!new_bus)
 240                 return -ENODEV;
 241
 242         if (pdev->dev.of_node)
 243                 ret = of_mdiobus_register(new_bus, pdev->dev.of_node);
 244         else
 245                 ret = mdiobus_register(new_bus);
 246
 247         if (ret)
 248                 mdio_gpio_bus_deinit(&pdev->dev);
 249
 250         return ret;
 251 }
 252
 253 static int mdio_gpio_remove(struct platform_device *pdev)
 254 {
 255         mdio_gpio_bus_destroy(&pdev->dev);
 256
 257         return 0;
 258 }
 259
 260 static const struct of_device_id mdio_gpio_of_match[] = {
 261         { .compatible = "virtual,mdio-gpio", },
 262         { /* sentinel */ }
 263 };
 264 MODULE_DEVICE_TABLE(of, mdio_gpio_of_match);
 265
 266 static struct platform_driver mdio_gpio_driver = {
 267         .probe = mdio_gpio_probe,
 268         .remove = mdio_gpio_remove,
 269         .driver         = {
 270                 .name   = "mdio-gpio",
 271                 .of_match_table = mdio_gpio_of_match,
 272         },
 273 };
 274
 275 module_platform_driver(mdio_gpio_driver);
 276
 277 MODULE_ALIAS("platform:mdio-gpio");
 278 MODULE_AUTHOR("Laurent Pinchart, Paulius Zaleckas");
 279 MODULE_LICENSE("GPL");
 280 MODULE_DESCRIPTION("Generic driver for MDIO bus emulation using GPIO");