drivers/net/phy/fixed_phy.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Fixed MDIO bus (MDIO bus emulation with fixed PHYs)
   4  *
   5  * Author: Vitaly Bordug <vbordug@ru.mvista.com>
   6  *         Anton Vorontsov <avorontsov@ru.mvista.com>
   7  *
   8  * Copyright (c) 2006-2007 MontaVista Software, Inc.
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/module.h>
  13 #include <linux/platform_device.h>
  14 #include <linux/list.h>
  15 #include <linux/mii.h>
  16 #include <linux/phy.h>
  17 #include <linux/phy_fixed.h>
  18 #include <linux/err.h>
  19 #include <linux/slab.h>
  20 #include <linux/of.h>
  21 #include <linux/gpio/consumer.h>
  22 #include <linux/idr.h>
  23 #include <linux/netdevice.h>
  24 #include <linux/linkmode.h>
  25
  26 #include "swphy.h"
  27
  28 struct fixed_mdio_bus {
  29         struct mii_bus *mii_bus;
  30         struct list_head phys;
  31 };
  32
  33 struct fixed_phy {
  34         int addr;
  35         struct phy_device *phydev;
  36         struct fixed_phy_status status;
  37         bool no_carrier;
  38         int (*link_update)(struct net_device *, struct fixed_phy_status *);
  39         struct list_head node;
  40         struct gpio_desc *link_gpiod;
  41 };
  42
  43 static struct platform_device *pdev;
  44 static struct fixed_mdio_bus platform_fmb = {
  45         .phys = LIST_HEAD_INIT(platform_fmb.phys),
  46 };
  47
  48 int fixed_phy_change_carrier(struct net_device *dev, bool new_carrier)
  49 {
  50         struct fixed_mdio_bus *fmb = &platform_fmb;
  51         struct phy_device *phydev = dev->phydev;
  52         struct fixed_phy *fp;
  53
  54         if (!phydev || !phydev->mdio.bus)
  55                 return -EINVAL;
  56
  57         list_for_each_entry(fp, &fmb->phys, node) {
  58                 if (fp->addr == phydev->mdio.addr) {
  59                         fp->no_carrier = !new_carrier;
  60                         return 0;
  61                 }
  62         }
  63         return -EINVAL;
  64 }
  65 EXPORT_SYMBOL_GPL(fixed_phy_change_carrier);
  66
  67 static void fixed_phy_update(struct fixed_phy *fp)
  68 {
  69         if (!fp->no_carrier && fp->link_gpiod)
  70                 fp->status.link = !!gpiod_get_value_cansleep(fp->link_gpiod);
  71 }
  72
  73 static int fixed_mdio_read(struct mii_bus *bus, int phy_addr, int reg_num)
  74 {
  75         struct fixed_mdio_bus *fmb = bus->priv;
  76         struct fixed_phy *fp;
  77
  78         list_for_each_entry(fp, &fmb->phys, node) {
  79                 if (fp->addr == phy_addr) {
  80                         struct fixed_phy_status state;
  81
  82                         fp->status.link = !fp->no_carrier;
  83
  84                         /* Issue callback if user registered it. */
  85                         if (fp->link_update)
  86                                 fp->link_update(fp->phydev->attached_dev,
  87                                                 &fp->status);
  88
  89                         /* Check the GPIO for change in status */
  90                         fixed_phy_update(fp);
  91                         state = fp->status;
  92
  93                         return swphy_read_reg(reg_num, &state);
  94                 }
  95         }
  96
  97         return 0xFFFF;
  98 }
  99
 100 static int fixed_mdio_write(struct mii_bus *bus, int phy_addr, int reg_num,
 101                             u16 val)
 102 {
 103         return 0;
 104 }
 105
 106 /*
 107  * If something weird is required to be done with link/speed,
 108  * network driver is able to assign a function to implement this.
 109  * May be useful for PHY's that need to be software-driven.
 110  */
 111 int fixed_phy_set_link_update(struct phy_device *phydev,
 112                               int (*link_update)(struct net_device *,
 113                                                  struct fixed_phy_status *))
 114 {
 115         struct fixed_mdio_bus *fmb = &platform_fmb;
 116         struct fixed_phy *fp;
 117
 118         if (!phydev || !phydev->mdio.bus)
 119                 return -EINVAL;
 120
 121         list_for_each_entry(fp, &fmb->phys, node) {
 122                 if (fp->addr == phydev->mdio.addr) {
 123                         fp->link_update = link_update;
 124                         fp->phydev = phydev;
 125                         return 0;
 126                 }
 127         }
 128
 129         return -ENOENT;
 130 }
 131 EXPORT_SYMBOL_GPL(fixed_phy_set_link_update);
 132
 133 static int fixed_phy_add_gpiod(unsigned int irq, int phy_addr,
 134                                struct fixed_phy_status *status,
 135                                struct gpio_desc *gpiod)
 136 {
 137         int ret;
 138         struct fixed_mdio_bus *fmb = &platform_fmb;
 139         struct fixed_phy *fp;
 140
 141         ret = swphy_validate_state(status);
 142         if (ret < 0)
 143                 return ret;
 144
 145         fp = kzalloc(sizeof(*fp), GFP_KERNEL);
 146         if (!fp)
 147                 return -ENOMEM;
 148
 149         if (irq != PHY_POLL)
 150                 fmb->mii_bus->irq[phy_addr] = irq;
 151
 152         fp->addr = phy_addr;
 153         fp->status = *status;
 154         fp->link_gpiod = gpiod;
 155
 156         fixed_phy_update(fp);
 157
 158         list_add_tail(&fp->node, &fmb->phys);
 159
 160         return 0;
 161 }
 162
 163 int fixed_phy_add(unsigned int irq, int phy_addr,
 164                   struct fixed_phy_status *status)
 165 {
 166         return fixed_phy_add_gpiod(irq, phy_addr, status, NULL);
 167 }
 168 EXPORT_SYMBOL_GPL(fixed_phy_add);
 169
 170 static DEFINE_IDA(phy_fixed_ida);
 171
 172 static void fixed_phy_del(int phy_addr)
 173 {
 174         struct fixed_mdio_bus *fmb = &platform_fmb;
 175         struct fixed_phy *fp, *tmp;
 176
 177         list_for_each_entry_safe(fp, tmp, &fmb->phys, node) {
 178                 if (fp->addr == phy_addr) {
 179                         list_del(&fp->node);
 180                         if (fp->link_gpiod)
 181                                 gpiod_put(fp->link_gpiod);
 182                         kfree(fp);
 183                         ida_free(&phy_fixed_ida, phy_addr);
 184                         return;
 185                 }
 186         }
 187 }
 188
 189 #ifdef CONFIG_OF_GPIO
 190 static struct gpio_desc *fixed_phy_get_gpiod(struct device_node *np)
 191 {
 192         struct device_node *fixed_link_node;
 193         struct gpio_desc *gpiod;
 194
 195         if (!np)
 196                 return NULL;
 197
 198         fixed_link_node = of_get_child_by_name(np, "fixed-link");
 199         if (!fixed_link_node)
 200                 return NULL;
 201
 202         /*
 203          * As the fixed link is just a device tree node without any
 204          * Linux device associated with it, we simply have obtain
 205          * the GPIO descriptor from the device tree like this.
 206          */
 207         gpiod = fwnode_gpiod_get_index(of_fwnode_handle(fixed_link_node),
 208                                        "link", 0, GPIOD_IN, "mdio");
 209         if (IS_ERR(gpiod) && PTR_ERR(gpiod) != -EPROBE_DEFER) {
 210                 if (PTR_ERR(gpiod) != -ENOENT)
 211                         pr_err("error getting GPIO for fixed link %pOF, proceed without\n",
 212                                fixed_link_node);
 213                 gpiod = NULL;
 214         }
 215         of_node_put(fixed_link_node);
 216
 217         return gpiod;
 218 }
 219 #else
 220 static struct gpio_desc *fixed_phy_get_gpiod(struct device_node *np)
 221 {
 222         return NULL;
 223 }
 224 #endif
 225
 226 static struct phy_device *__fixed_phy_register(unsigned int irq,
 227                                                struct fixed_phy_status *status,
 228                                                struct device_node *np,
 229                                                struct gpio_desc *gpiod)
 230 {
 231         struct fixed_mdio_bus *fmb = &platform_fmb;
 232         struct phy_device *phy;
 233         int phy_addr;
 234         int ret;
 235
 236         if (!fmb->mii_bus || fmb->mii_bus->state != MDIOBUS_REGISTERED)
 237                 return ERR_PTR(-EPROBE_DEFER);
 238
 239         /* Check if we have a GPIO associated with this fixed phy */
 240         if (!gpiod) {
 241                 gpiod = fixed_phy_get_gpiod(np);
 242                 if (IS_ERR(gpiod))
 243                         return ERR_CAST(gpiod);
 244         }
 245
 246         /* Get the next available PHY address, up to PHY_MAX_ADDR */
 247         phy_addr = ida_alloc_max(&phy_fixed_ida, PHY_MAX_ADDR - 1, GFP_KERNEL);
 248         if (phy_addr < 0)
 249                 return ERR_PTR(phy_addr);
 250
 251         ret = fixed_phy_add_gpiod(irq, phy_addr, status, gpiod);
 252         if (ret < 0) {
 253                 ida_free(&phy_fixed_ida, phy_addr);
 254                 return ERR_PTR(ret);
 255         }
 256
 257         phy = get_phy_device(fmb->mii_bus, phy_addr, false);
 258         if (IS_ERR(phy)) {
 259                 fixed_phy_del(phy_addr);
 260                 return ERR_PTR(-EINVAL);
 261         }
 262
 263         /* propagate the fixed link values to struct phy_device */
 264         phy->link = status->link;
 265         if (status->link) {
 266                 phy->speed = status->speed;
 267                 phy->duplex = status->duplex;
 268                 phy->pause = status->pause;
 269                 phy->asym_pause = status->asym_pause;
 270         }
 271
 272         of_node_get(np);
 273         phy->mdio.dev.of_node = np;
 274         phy->is_pseudo_fixed_link = true;
 275
 276         switch (status->speed) {
 277         case SPEED_1000:
 278                 linkmode_set_bit(ETHTOOL_LINK_MODE_1000baseT_Half_BIT,
 279                                  phy->supported);
 280                 linkmode_set_bit(ETHTOOL_LINK_MODE_1000baseT_Full_BIT,
 281                                  phy->supported);
 282                 fallthrough;
 283         case SPEED_100:
 284                 linkmode_set_bit(ETHTOOL_LINK_MODE_100baseT_Half_BIT,
 285                                  phy->supported);
 286                 linkmode_set_bit(ETHTOOL_LINK_MODE_100baseT_Full_BIT,
 287                                  phy->supported);
 288                 fallthrough;
 289         case SPEED_10:
 290         default:
 291                 linkmode_set_bit(ETHTOOL_LINK_MODE_10baseT_Half_BIT,
 292                                  phy->supported);
 293                 linkmode_set_bit(ETHTOOL_LINK_MODE_10baseT_Full_BIT,
 294                                  phy->supported);
 295         }
 296
 297         phy_advertise_supported(phy);
 298
 299         ret = phy_device_register(phy);
 300         if (ret) {
 301                 phy_device_free(phy);
 302                 of_node_put(np);
 303                 fixed_phy_del(phy_addr);
 304                 return ERR_PTR(ret);
 305         }
 306
 307         return phy;
 308 }
 309
 310 struct phy_device *fixed_phy_register(unsigned int irq,
 311                                       struct fixed_phy_status *status,
 312                                       struct device_node *np)
 313 {
 314         return __fixed_phy_register(irq, status, np, NULL);
 315 }
 316 EXPORT_SYMBOL_GPL(fixed_phy_register);
 317
 318 struct phy_device *
 319 fixed_phy_register_with_gpiod(unsigned int irq,
 320                               struct fixed_phy_status *status,
 321                               struct gpio_desc *gpiod)
 322 {
 323         return __fixed_phy_register(irq, status, NULL, gpiod);
 324 }
 325 EXPORT_SYMBOL_GPL(fixed_phy_register_with_gpiod);
 326
 327 void fixed_phy_unregister(struct phy_device *phy)
 328 {
 329         phy_device_remove(phy);
 330         of_node_put(phy->mdio.dev.of_node);
 331         fixed_phy_del(phy->mdio.addr);
 332 }
 333 EXPORT_SYMBOL_GPL(fixed_phy_unregister);
 334
 335 static int __init fixed_mdio_bus_init(void)
 336 {
 337         struct fixed_mdio_bus *fmb = &platform_fmb;
 338         int ret;
 339
 340         pdev = platform_device_register_simple("Fixed MDIO bus", 0, NULL, 0);
 341         if (IS_ERR(pdev))
 342                 return PTR_ERR(pdev);
 343
 344         fmb->mii_bus = mdiobus_alloc();
 345         if (fmb->mii_bus == NULL) {
 346                 ret = -ENOMEM;
 347                 goto err_mdiobus_reg;
 348         }
 349
 350         snprintf(fmb->mii_bus->id, MII_BUS_ID_SIZE, "fixed-0");
 351         fmb->mii_bus->name = "Fixed MDIO Bus";
 352         fmb->mii_bus->priv = fmb;
 353         fmb->mii_bus->parent = &pdev->dev;
 354         fmb->mii_bus->read = &fixed_mdio_read;
 355         fmb->mii_bus->write = &fixed_mdio_write;
 356         fmb->mii_bus->phy_mask = ~0;
 357
 358         ret = mdiobus_register(fmb->mii_bus);
 359         if (ret)
 360                 goto err_mdiobus_alloc;
 361
 362         return 0;
 363
 364 err_mdiobus_alloc:
 365         mdiobus_free(fmb->mii_bus);
 366 err_mdiobus_reg:
 367         platform_device_unregister(pdev);
 368         return ret;
 369 }
 370 module_init(fixed_mdio_bus_init);
 371
 372 static void __exit fixed_mdio_bus_exit(void)
 373 {
 374         struct fixed_mdio_bus *fmb = &platform_fmb;
 375         struct fixed_phy *fp, *tmp;
 376
 377         mdiobus_unregister(fmb->mii_bus);
 378         mdiobus_free(fmb->mii_bus);
 379         platform_device_unregister(pdev);
 380
 381         list_for_each_entry_safe(fp, tmp, &fmb->phys, node) {
 382                 list_del(&fp->node);
 383                 kfree(fp);
 384         }
 385         ida_destroy(&phy_fixed_ida);
 386 }
 387 module_exit(fixed_mdio_bus_exit);
 388
 389 MODULE_DESCRIPTION("Fixed MDIO bus (MDIO bus emulation with fixed PHYs)");
 390 MODULE_AUTHOR("Vitaly Bordug");
 391 MODULE_LICENSE("GPL");