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/seqlock.h>
  23 #include <linux/idr.h>
  24 #include <linux/netdevice.h>
  25 #include <linux/linkmode.h>
  26
  27 #include "swphy.h"
  28
  29 struct fixed_mdio_bus {
  30         struct mii_bus *mii_bus;
  31         struct list_head phys;
  32 };
  33
  34 struct fixed_phy {
  35         int addr;
  36         struct phy_device *phydev;
  37         seqcount_t seqcount;
  38         struct fixed_phy_status status;
  39         bool no_carrier;
  40         int (*link_update)(struct net_device *, struct fixed_phy_status *);
  41         struct list_head node;
  42         struct gpio_desc *link_gpiod;
  43 };
  44
  45 static struct platform_device *pdev;
  46 static struct fixed_mdio_bus platform_fmb = {
  47         .phys = LIST_HEAD_INIT(platform_fmb.phys),
  48 };
  49
  50 int fixed_phy_change_carrier(struct net_device *dev, bool new_carrier)
  51 {
  52         struct fixed_mdio_bus *fmb = &platform_fmb;
  53         struct phy_device *phydev = dev->phydev;
  54         struct fixed_phy *fp;
  55
  56         if (!phydev || !phydev->mdio.bus)
  57                 return -EINVAL;
  58
  59         list_for_each_entry(fp, &fmb->phys, node) {
  60                 if (fp->addr == phydev->mdio.addr) {
  61                         fp->no_carrier = !new_carrier;
  62                         return 0;
  63                 }
  64         }
  65         return -EINVAL;
  66 }
  67 EXPORT_SYMBOL_GPL(fixed_phy_change_carrier);
  68
  69 static void fixed_phy_update(struct fixed_phy *fp)
  70 {
  71         if (!fp->no_carrier && fp->link_gpiod)
  72                 fp->status.link = !!gpiod_get_value_cansleep(fp->link_gpiod);
  73 }
  74
  75 static int fixed_mdio_read(struct mii_bus *bus, int phy_addr, int reg_num)
  76 {
  77         struct fixed_mdio_bus *fmb = bus->priv;
  78         struct fixed_phy *fp;
  79
  80         list_for_each_entry(fp, &fmb->phys, node) {
  81                 if (fp->addr == phy_addr) {
  82                         struct fixed_phy_status state;
  83                         int s;
  84
  85                         do {
  86                                 s = read_seqcount_begin(&fp->seqcount);
  87                                 fp->status.link = !fp->no_carrier;
  88                                 /* Issue callback if user registered it. */
  89                                 if (fp->link_update)
  90                                         fp->link_update(fp->phydev->attached_dev,
  91                                                         &fp->status);
  92                                 /* Check the GPIO for change in status */
  93                                 fixed_phy_update(fp);
  94                                 state = fp->status;
  95                         } while (read_seqcount_retry(&fp->seqcount, s));
  96
  97                         return swphy_read_reg(reg_num, &state);
  98                 }
  99         }
 100
 101         return 0xFFFF;
 102 }
 103
 104 static int fixed_mdio_write(struct mii_bus *bus, int phy_addr, int reg_num,
 105                             u16 val)
 106 {
 107         return 0;
 108 }
 109
 110 /*
 111  * If something weird is required to be done with link/speed,
 112  * network driver is able to assign a function to implement this.
 113  * May be useful for PHY's that need to be software-driven.
 114  */
 115 int fixed_phy_set_link_update(struct phy_device *phydev,
 116                               int (*link_update)(struct net_device *,
 117                                                  struct fixed_phy_status *))
 118 {
 119         struct fixed_mdio_bus *fmb = &platform_fmb;
 120         struct fixed_phy *fp;
 121
 122         if (!phydev || !phydev->mdio.bus)
 123                 return -EINVAL;
 124
 125         list_for_each_entry(fp, &fmb->phys, node) {
 126                 if (fp->addr == phydev->mdio.addr) {
 127                         fp->link_update = link_update;
 128                         fp->phydev = phydev;
 129                         return 0;
 130                 }
 131         }
 132
 133         return -ENOENT;
 134 }
 135 EXPORT_SYMBOL_GPL(fixed_phy_set_link_update);
 136
 137 static int fixed_phy_add_gpiod(unsigned int irq, int phy_addr,
 138                                struct fixed_phy_status *status,
 139                                struct gpio_desc *gpiod)
 140 {
 141         int ret;
 142         struct fixed_mdio_bus *fmb = &platform_fmb;
 143         struct fixed_phy *fp;
 144
 145         ret = swphy_validate_state(status);
 146         if (ret < 0)
 147                 return ret;
 148
 149         fp = kzalloc(sizeof(*fp), GFP_KERNEL);
 150         if (!fp)
 151                 return -ENOMEM;
 152
 153         seqcount_init(&fp->seqcount);
 154
 155         if (irq != PHY_POLL)
 156                 fmb->mii_bus->irq[phy_addr] = irq;
 157
 158         fp->addr = phy_addr;
 159         fp->status = *status;
 160         fp->link_gpiod = gpiod;
 161
 162         fixed_phy_update(fp);
 163
 164         list_add_tail(&fp->node, &fmb->phys);
 165
 166         return 0;
 167 }
 168
 169 int fixed_phy_add(unsigned int irq, int phy_addr,
 170                   struct fixed_phy_status *status) {
 171
 172         return fixed_phy_add_gpiod(irq, phy_addr, status, NULL);
 173 }
 174 EXPORT_SYMBOL_GPL(fixed_phy_add);
 175
 176 static DEFINE_IDA(phy_fixed_ida);
 177
 178 static void fixed_phy_del(int phy_addr)
 179 {
 180         struct fixed_mdio_bus *fmb = &platform_fmb;
 181         struct fixed_phy *fp, *tmp;
 182
 183         list_for_each_entry_safe(fp, tmp, &fmb->phys, node) {
 184                 if (fp->addr == phy_addr) {
 185                         list_del(&fp->node);
 186                         if (fp->link_gpiod)
 187                                 gpiod_put(fp->link_gpiod);
 188                         kfree(fp);
 189                         ida_simple_remove(&phy_fixed_ida, phy_addr);
 190                         return;
 191                 }
 192         }
 193 }
 194
 195 #ifdef CONFIG_OF_GPIO
 196 static struct gpio_desc *fixed_phy_get_gpiod(struct device_node *np)
 197 {
 198         struct device_node *fixed_link_node;
 199         struct gpio_desc *gpiod;
 200
 201         if (!np)
 202                 return NULL;
 203
 204         fixed_link_node = of_get_child_by_name(np, "fixed-link");
 205         if (!fixed_link_node)
 206                 return NULL;
 207
 208         /*
 209          * As the fixed link is just a device tree node without any
 210          * Linux device associated with it, we simply have obtain
 211          * the GPIO descriptor from the device tree like this.
 212          */
 213         gpiod = gpiod_get_from_of_node(fixed_link_node, "link-gpios", 0,
 214                                        GPIOD_IN, "mdio");
 215         of_node_put(fixed_link_node);
 216         if (IS_ERR(gpiod)) {
 217                 if (PTR_ERR(gpiod) == -EPROBE_DEFER)
 218                         return gpiod;
 219                 pr_err("error getting GPIO for fixed link %pOF, proceed without\n",
 220                        fixed_link_node);
 221                 gpiod = NULL;
 222         }
 223
 224         return gpiod;
 225 }
 226 #else
 227 static struct gpio_desc *fixed_phy_get_gpiod(struct device_node *np)
 228 {
 229         return NULL;
 230 }
 231 #endif
 232
 233 static struct phy_device *__fixed_phy_register(unsigned int irq,
 234                                                struct fixed_phy_status *status,
 235                                                struct device_node *np,
 236                                                struct gpio_desc *gpiod)
 237 {
 238         struct fixed_mdio_bus *fmb = &platform_fmb;
 239         struct phy_device *phy;
 240         int phy_addr;
 241         int ret;
 242
 243         if (!fmb->mii_bus || fmb->mii_bus->state != MDIOBUS_REGISTERED)
 244                 return ERR_PTR(-EPROBE_DEFER);
 245
 246         /* Check if we have a GPIO associated with this fixed phy */
 247         if (!gpiod) {
 248                 gpiod = fixed_phy_get_gpiod(np);
 249                 if (IS_ERR(gpiod))
 250                         return ERR_CAST(gpiod);
 251         }
 252
 253         /* Get the next available PHY address, up to PHY_MAX_ADDR */
 254         phy_addr = ida_simple_get(&phy_fixed_ida, 0, PHY_MAX_ADDR, GFP_KERNEL);
 255         if (phy_addr < 0)
 256                 return ERR_PTR(phy_addr);
 257
 258         ret = fixed_phy_add_gpiod(irq, phy_addr, status, gpiod);
 259         if (ret < 0) {
 260                 ida_simple_remove(&phy_fixed_ida, phy_addr);
 261                 return ERR_PTR(ret);
 262         }
 263
 264         phy = get_phy_device(fmb->mii_bus, phy_addr, false);
 265         if (IS_ERR(phy)) {
 266                 fixed_phy_del(phy_addr);
 267                 return ERR_PTR(-EINVAL);
 268         }
 269
 270         /* propagate the fixed link values to struct phy_device */
 271         phy->link = status->link;
 272         if (status->link) {
 273                 phy->speed = status->speed;
 274                 phy->duplex = status->duplex;
 275                 phy->pause = status->pause;
 276                 phy->asym_pause = status->asym_pause;
 277         }
 278
 279         of_node_get(np);
 280         phy->mdio.dev.of_node = np;
 281         phy->is_pseudo_fixed_link = true;
 282
 283         switch (status->speed) {
 284         case SPEED_1000:
 285                 linkmode_set_bit(ETHTOOL_LINK_MODE_1000baseT_Half_BIT,
 286                                  phy->supported);
 287                 linkmode_set_bit(ETHTOOL_LINK_MODE_1000baseT_Full_BIT,
 288                                  phy->supported);
 289                 /* fall through */
 290         case SPEED_100:
 291                 linkmode_set_bit(ETHTOOL_LINK_MODE_100baseT_Half_BIT,
 292                                  phy->supported);
 293                 linkmode_set_bit(ETHTOOL_LINK_MODE_100baseT_Full_BIT,
 294                                  phy->supported);
 295                 /* fall through */
 296         case SPEED_10:
 297         default:
 298                 linkmode_set_bit(ETHTOOL_LINK_MODE_10baseT_Half_BIT,
 299                                  phy->supported);
 300                 linkmode_set_bit(ETHTOOL_LINK_MODE_10baseT_Full_BIT,
 301                                  phy->supported);
 302         }
 303
 304         linkmode_copy(phy->advertising, phy->supported);
 305
 306         ret = phy_device_register(phy);
 307         if (ret) {
 308                 phy_device_free(phy);
 309                 of_node_put(np);
 310                 fixed_phy_del(phy_addr);
 311                 return ERR_PTR(ret);
 312         }
 313
 314         return phy;
 315 }
 316
 317 struct phy_device *fixed_phy_register(unsigned int irq,
 318                                       struct fixed_phy_status *status,
 319                                       struct device_node *np)
 320 {
 321         return __fixed_phy_register(irq, status, np, NULL);
 322 }
 323 EXPORT_SYMBOL_GPL(fixed_phy_register);
 324
 325 struct phy_device *
 326 fixed_phy_register_with_gpiod(unsigned int irq,
 327                               struct fixed_phy_status *status,
 328                               struct gpio_desc *gpiod)
 329 {
 330         return __fixed_phy_register(irq, status, NULL, gpiod);
 331 }
 332 EXPORT_SYMBOL_GPL(fixed_phy_register_with_gpiod);
 333
 334 void fixed_phy_unregister(struct phy_device *phy)
 335 {
 336         phy_device_remove(phy);
 337         of_node_put(phy->mdio.dev.of_node);
 338         fixed_phy_del(phy->mdio.addr);
 339 }
 340 EXPORT_SYMBOL_GPL(fixed_phy_unregister);
 341
 342 static int __init fixed_mdio_bus_init(void)
 343 {
 344         struct fixed_mdio_bus *fmb = &platform_fmb;
 345         int ret;
 346
 347         pdev = platform_device_register_simple("Fixed MDIO bus", 0, NULL, 0);
 348         if (IS_ERR(pdev))
 349                 return PTR_ERR(pdev);
 350
 351         fmb->mii_bus = mdiobus_alloc();
 352         if (fmb->mii_bus == NULL) {
 353                 ret = -ENOMEM;
 354                 goto err_mdiobus_reg;
 355         }
 356
 357         snprintf(fmb->mii_bus->id, MII_BUS_ID_SIZE, "fixed-0");
 358         fmb->mii_bus->name = "Fixed MDIO Bus";
 359         fmb->mii_bus->priv = fmb;
 360         fmb->mii_bus->parent = &pdev->dev;
 361         fmb->mii_bus->read = &fixed_mdio_read;
 362         fmb->mii_bus->write = &fixed_mdio_write;
 363
 364         ret = mdiobus_register(fmb->mii_bus);
 365         if (ret)
 366                 goto err_mdiobus_alloc;
 367
 368         return 0;
 369
 370 err_mdiobus_alloc:
 371         mdiobus_free(fmb->mii_bus);
 372 err_mdiobus_reg:
 373         platform_device_unregister(pdev);
 374         return ret;
 375 }
 376 module_init(fixed_mdio_bus_init);
 377
 378 static void __exit fixed_mdio_bus_exit(void)
 379 {
 380         struct fixed_mdio_bus *fmb = &platform_fmb;
 381         struct fixed_phy *fp, *tmp;
 382
 383         mdiobus_unregister(fmb->mii_bus);
 384         mdiobus_free(fmb->mii_bus);
 385         platform_device_unregister(pdev);
 386
 387         list_for_each_entry_safe(fp, tmp, &fmb->phys, node) {
 388                 list_del(&fp->node);
 389                 kfree(fp);
 390         }
 391         ida_destroy(&phy_fixed_ida);
 392 }
 393 module_exit(fixed_mdio_bus_exit);
 394
 395 MODULE_DESCRIPTION("Fixed MDIO bus (MDIO bus emulation with fixed PHYs)");
 396 MODULE_AUTHOR("Vitaly Bordug");
 397 MODULE_LICENSE("GPL");