root/drivers/of/platform.c

DEFINITIONS

1. of_find_device_by_node
2. of_device_make_bus_id
3. of_device_alloc
4. of_platform_device_create_pdata
5. of_platform_device_create
6. of_amba_device_create
7. of_amba_device_create
8. of_dev_lookup
9. of_platform_bus_create
10. of_platform_bus_probe
11. of_platform_populate
12. of_platform_default_populate
13. of_platform_default_populate_init
14. of_platform_device_destroy
15. of_platform_depopulate
16. devm_of_platform_populate_release
17. devm_of_platform_populate
18. devm_of_platform_match
19. devm_of_platform_depopulate
20. of_platform_notify
21. of_platform_register_reconfig_notifier

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  *    Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corp.
   4  *                       <benh@kernel.crashing.org>
   5  *    and                Arnd Bergmann, IBM Corp.
   6  *    Merged from powerpc/kernel/of_platform.c and
   7  *    sparc{,64}/kernel/of_device.c by Stephen Rothwell
   8  */
   9 
  10 #define pr_fmt(fmt)     "OF: " fmt
  11 
  12 #include <linux/errno.h>
  13 #include <linux/module.h>
  14 #include <linux/amba/bus.h>
  15 #include <linux/device.h>
  16 #include <linux/dma-mapping.h>
  17 #include <linux/slab.h>
  18 #include <linux/of_address.h>
  19 #include <linux/of_device.h>
  20 #include <linux/of_iommu.h>
  21 #include <linux/of_irq.h>
  22 #include <linux/of_platform.h>
  23 #include <linux/platform_device.h>
  24 
  25 const struct of_device_id of_default_bus_match_table[] = {
  26         { .compatible = "simple-bus", },
  27         { .compatible = "simple-mfd", },
  28         { .compatible = "isa", },
  29 #ifdef CONFIG_ARM_AMBA
  30         { .compatible = "arm,amba-bus", },
  31 #endif /* CONFIG_ARM_AMBA */
  32         {} /* Empty terminated list */
  33 };
  34 
  35 static const struct of_device_id of_skipped_node_table[] = {
  36         { .compatible = "operating-points-v2", },
  37         {} /* Empty terminated list */
  38 };
  39 
  40 /**
  41  * of_find_device_by_node - Find the platform_device associated with a node
  42  * @np: Pointer to device tree node
  43  *
  44  * Takes a reference to the embedded struct device which needs to be dropped
  45  * after use.
  46  *
  47  * Returns platform_device pointer, or NULL if not found
  48  */
  49 struct platform_device *of_find_device_by_node(struct device_node *np)
  50 {
  51         struct device *dev;
  52 
  53         dev = bus_find_device_by_of_node(&platform_bus_type, np);
  54         return dev ? to_platform_device(dev) : NULL;
  55 }
  56 EXPORT_SYMBOL(of_find_device_by_node);
  57 
  58 #ifdef CONFIG_OF_ADDRESS
  59 /*
  60  * The following routines scan a subtree and registers a device for
  61  * each applicable node.
  62  *
  63  * Note: sparc doesn't use these routines because it has a different
  64  * mechanism for creating devices from device tree nodes.
  65  */
  66 
  67 /**
  68  * of_device_make_bus_id - Use the device node data to assign a unique name
  69  * @dev: pointer to device structure that is linked to a device tree node
  70  *
  71  * This routine will first try using the translated bus address to
  72  * derive a unique name. If it cannot, then it will prepend names from
  73  * parent nodes until a unique name can be derived.
  74  */
  75 static void of_device_make_bus_id(struct device *dev)
  76 {
  77         struct device_node *node = dev->of_node;
  78         const __be32 *reg;
  79         u64 addr;
  80 
  81         /* Construct the name, using parent nodes if necessary to ensure uniqueness */
  82         while (node->parent) {
  83                 /*
  84                  * If the address can be translated, then that is as much
  85                  * uniqueness as we need. Make it the first component and return
  86                  */
  87                 reg = of_get_property(node, "reg", NULL);
  88                 if (reg && (addr = of_translate_address(node, reg)) != OF_BAD_ADDR) {
  89                         dev_set_name(dev, dev_name(dev) ? "%llx.%pOFn:%s" : "%llx.%pOFn",
  90                                      addr, node, dev_name(dev));
  91                         return;
  92                 }
  93 
  94                 /* format arguments only used if dev_name() resolves to NULL */
  95                 dev_set_name(dev, dev_name(dev) ? "%s:%s" : "%s",
  96                              kbasename(node->full_name), dev_name(dev));
  97                 node = node->parent;
  98         }
  99 }
 100 
 101 /**
 102  * of_device_alloc - Allocate and initialize an of_device
 103  * @np: device node to assign to device
 104  * @bus_id: Name to assign to the device.  May be null to use default name.
 105  * @parent: Parent device.
 106  */
 107 struct platform_device *of_device_alloc(struct device_node *np,
 108                                   const char *bus_id,
 109                                   struct device *parent)
 110 {
 111         struct platform_device *dev;
 112         int rc, i, num_reg = 0, num_irq;
 113         struct resource *res, temp_res;
 114 
 115         dev = platform_device_alloc("", PLATFORM_DEVID_NONE);
 116         if (!dev)
 117                 return NULL;
 118 
 119         /* count the io and irq resources */
 120         while (of_address_to_resource(np, num_reg, &temp_res) == 0)
 121                 num_reg++;
 122         num_irq = of_irq_count(np);
 123 
 124         /* Populate the resource table */
 125         if (num_irq || num_reg) {
 126                 res = kcalloc(num_irq + num_reg, sizeof(*res), GFP_KERNEL);
 127                 if (!res) {
 128                         platform_device_put(dev);
 129                         return NULL;
 130                 }
 131 
 132                 dev->num_resources = num_reg + num_irq;
 133                 dev->resource = res;
 134                 for (i = 0; i < num_reg; i++, res++) {
 135                         rc = of_address_to_resource(np, i, res);
 136                         WARN_ON(rc);
 137                 }
 138                 if (of_irq_to_resource_table(np, res, num_irq) != num_irq)
 139                         pr_debug("not all legacy IRQ resources mapped for %pOFn\n",
 140                                  np);
 141         }
 142 
 143         dev->dev.of_node = of_node_get(np);
 144         dev->dev.fwnode = &np->fwnode;
 145         dev->dev.parent = parent ? : &platform_bus;
 146 
 147         if (bus_id)
 148                 dev_set_name(&dev->dev, "%s", bus_id);
 149         else
 150                 of_device_make_bus_id(&dev->dev);
 151 
 152         return dev;
 153 }
 154 EXPORT_SYMBOL(of_device_alloc);
 155 
 156 /**
 157  * of_platform_device_create_pdata - Alloc, initialize and register an of_device
 158  * @np: pointer to node to create device for
 159  * @bus_id: name to assign device
 160  * @platform_data: pointer to populate platform_data pointer with
 161  * @parent: Linux device model parent device.
 162  *
 163  * Returns pointer to created platform device, or NULL if a device was not
 164  * registered.  Unavailable devices will not get registered.
 165  */
 166 static struct platform_device *of_platform_device_create_pdata(
 167                                         struct device_node *np,
 168                                         const char *bus_id,
 169                                         void *platform_data,
 170                                         struct device *parent)
 171 {
 172         struct platform_device *dev;
 173 
 174         if (!of_device_is_available(np) ||
 175             of_node_test_and_set_flag(np, OF_POPULATED))
 176                 return NULL;
 177 
 178         dev = of_device_alloc(np, bus_id, parent);
 179         if (!dev)
 180                 goto err_clear_flag;
 181 
 182         dev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
 183         if (!dev->dev.dma_mask)
 184                 dev->dev.dma_mask = &dev->dev.coherent_dma_mask;
 185         dev->dev.bus = &platform_bus_type;
 186         dev->dev.platform_data = platform_data;
 187         of_msi_configure(&dev->dev, dev->dev.of_node);
 188 
 189         if (of_device_add(dev) != 0) {
 190                 platform_device_put(dev);
 191                 goto err_clear_flag;
 192         }
 193 
 194         return dev;
 195 
 196 err_clear_flag:
 197         of_node_clear_flag(np, OF_POPULATED);
 198         return NULL;
 199 }
 200 
 201 /**
 202  * of_platform_device_create - Alloc, initialize and register an of_device
 203  * @np: pointer to node to create device for
 204  * @bus_id: name to assign device
 205  * @parent: Linux device model parent device.
 206  *
 207  * Returns pointer to created platform device, or NULL if a device was not
 208  * registered.  Unavailable devices will not get registered.
 209  */
 210 struct platform_device *of_platform_device_create(struct device_node *np,
 211                                             const char *bus_id,
 212                                             struct device *parent)
 213 {
 214         return of_platform_device_create_pdata(np, bus_id, NULL, parent);
 215 }
 216 EXPORT_SYMBOL(of_platform_device_create);
 217 
 218 #ifdef CONFIG_ARM_AMBA
 219 static struct amba_device *of_amba_device_create(struct device_node *node,
 220                                                  const char *bus_id,
 221                                                  void *platform_data,
 222                                                  struct device *parent)
 223 {
 224         struct amba_device *dev;
 225         const void *prop;
 226         int i, ret;
 227 
 228         pr_debug("Creating amba device %pOF\n", node);
 229 
 230         if (!of_device_is_available(node) ||
 231             of_node_test_and_set_flag(node, OF_POPULATED))
 232                 return NULL;
 233 
 234         dev = amba_device_alloc(NULL, 0, 0);
 235         if (!dev)
 236                 goto err_clear_flag;
 237 
 238         /* AMBA devices only support a single DMA mask */
 239         dev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
 240         dev->dev.dma_mask = &dev->dev.coherent_dma_mask;
 241 
 242         /* setup generic device info */
 243         dev->dev.of_node = of_node_get(node);
 244         dev->dev.fwnode = &node->fwnode;
 245         dev->dev.parent = parent ? : &platform_bus;
 246         dev->dev.platform_data = platform_data;
 247         if (bus_id)
 248                 dev_set_name(&dev->dev, "%s", bus_id);
 249         else
 250                 of_device_make_bus_id(&dev->dev);
 251 
 252         /* Allow the HW Peripheral ID to be overridden */
 253         prop = of_get_property(node, "arm,primecell-periphid", NULL);
 254         if (prop)
 255                 dev->periphid = of_read_ulong(prop, 1);
 256 
 257         /* Decode the IRQs and address ranges */
 258         for (i = 0; i < AMBA_NR_IRQS; i++)
 259                 dev->irq[i] = irq_of_parse_and_map(node, i);
 260 
 261         ret = of_address_to_resource(node, 0, &dev->res);
 262         if (ret) {
 263                 pr_err("amba: of_address_to_resource() failed (%d) for %pOF\n",
 264                        ret, node);
 265                 goto err_free;
 266         }
 267 
 268         ret = amba_device_add(dev, &iomem_resource);
 269         if (ret) {
 270                 pr_err("amba_device_add() failed (%d) for %pOF\n",
 271                        ret, node);
 272                 goto err_free;
 273         }
 274 
 275         return dev;
 276 
 277 err_free:
 278         amba_device_put(dev);
 279 err_clear_flag:
 280         of_node_clear_flag(node, OF_POPULATED);
 281         return NULL;
 282 }
 283 #else /* CONFIG_ARM_AMBA */
 284 static struct amba_device *of_amba_device_create(struct device_node *node,
 285                                                  const char *bus_id,
 286                                                  void *platform_data,
 287                                                  struct device *parent)
 288 {
 289         return NULL;
 290 }
 291 #endif /* CONFIG_ARM_AMBA */
 292 
 293 /**
 294  * of_devname_lookup() - Given a device node, lookup the preferred Linux name
 295  */
 296 static const struct of_dev_auxdata *of_dev_lookup(const struct of_dev_auxdata *lookup,
 297                                  struct device_node *np)
 298 {
 299         const struct of_dev_auxdata *auxdata;
 300         struct resource res;
 301         int compatible = 0;
 302 
 303         if (!lookup)
 304                 return NULL;
 305 
 306         auxdata = lookup;
 307         for (; auxdata->compatible; auxdata++) {
 308                 if (!of_device_is_compatible(np, auxdata->compatible))
 309                         continue;
 310                 compatible++;
 311                 if (!of_address_to_resource(np, 0, &res))
 312                         if (res.start != auxdata->phys_addr)
 313                                 continue;
 314                 pr_debug("%pOF: devname=%s\n", np, auxdata->name);
 315                 return auxdata;
 316         }
 317 
 318         if (!compatible)
 319                 return NULL;
 320 
 321         /* Try compatible match if no phys_addr and name are specified */
 322         auxdata = lookup;
 323         for (; auxdata->compatible; auxdata++) {
 324                 if (!of_device_is_compatible(np, auxdata->compatible))
 325                         continue;
 326                 if (!auxdata->phys_addr && !auxdata->name) {
 327                         pr_debug("%pOF: compatible match\n", np);
 328                         return auxdata;
 329                 }
 330         }
 331 
 332         return NULL;
 333 }
 334 
 335 /**
 336  * of_platform_bus_create() - Create a device for a node and its children.
 337  * @bus: device node of the bus to instantiate
 338  * @matches: match table for bus nodes
 339  * @lookup: auxdata table for matching id and platform_data with device nodes
 340  * @parent: parent for new device, or NULL for top level.
 341  * @strict: require compatible property
 342  *
 343  * Creates a platform_device for the provided device_node, and optionally
 344  * recursively create devices for all the child nodes.
 345  */
 346 static int of_platform_bus_create(struct device_node *bus,
 347                                   const struct of_device_id *matches,
 348                                   const struct of_dev_auxdata *lookup,
 349                                   struct device *parent, bool strict)
 350 {
 351         const struct of_dev_auxdata *auxdata;
 352         struct device_node *child;
 353         struct platform_device *dev;
 354         const char *bus_id = NULL;
 355         void *platform_data = NULL;
 356         int rc = 0;
 357 
 358         /* Make sure it has a compatible property */
 359         if (strict && (!of_get_property(bus, "compatible", NULL))) {
 360                 pr_debug("%s() - skipping %pOF, no compatible prop\n",
 361                          __func__, bus);
 362                 return 0;
 363         }
 364 
 365         /* Skip nodes for which we don't want to create devices */
 366         if (unlikely(of_match_node(of_skipped_node_table, bus))) {
 367                 pr_debug("%s() - skipping %pOF node\n", __func__, bus);
 368                 return 0;
 369         }
 370 
 371         if (of_node_check_flag(bus, OF_POPULATED_BUS)) {
 372                 pr_debug("%s() - skipping %pOF, already populated\n",
 373                         __func__, bus);
 374                 return 0;
 375         }
 376 
 377         auxdata = of_dev_lookup(lookup, bus);
 378         if (auxdata) {
 379                 bus_id = auxdata->name;
 380                 platform_data = auxdata->platform_data;
 381         }
 382 
 383         if (of_device_is_compatible(bus, "arm,primecell")) {
 384                 /*
 385                  * Don't return an error here to keep compatibility with older
 386                  * device tree files.
 387                  */
 388                 of_amba_device_create(bus, bus_id, platform_data, parent);
 389                 return 0;
 390         }
 391 
 392         dev = of_platform_device_create_pdata(bus, bus_id, platform_data, parent);
 393         if (!dev || !of_match_node(matches, bus))
 394                 return 0;
 395 
 396         for_each_child_of_node(bus, child) {
 397                 pr_debug("   create child: %pOF\n", child);
 398                 rc = of_platform_bus_create(child, matches, lookup, &dev->dev, strict);
 399                 if (rc) {
 400                         of_node_put(child);
 401                         break;
 402                 }
 403         }
 404         of_node_set_flag(bus, OF_POPULATED_BUS);
 405         return rc;
 406 }
 407 
 408 /**
 409  * of_platform_bus_probe() - Probe the device-tree for platform buses
 410  * @root: parent of the first level to probe or NULL for the root of the tree
 411  * @matches: match table for bus nodes
 412  * @parent: parent to hook devices from, NULL for toplevel
 413  *
 414  * Note that children of the provided root are not instantiated as devices
 415  * unless the specified root itself matches the bus list and is not NULL.
 416  */
 417 int of_platform_bus_probe(struct device_node *root,
 418                           const struct of_device_id *matches,
 419                           struct device *parent)
 420 {
 421         struct device_node *child;
 422         int rc = 0;
 423 
 424         root = root ? of_node_get(root) : of_find_node_by_path("/");
 425         if (!root)
 426                 return -EINVAL;
 427 
 428         pr_debug("%s()\n", __func__);
 429         pr_debug(" starting at: %pOF\n", root);
 430 
 431         /* Do a self check of bus type, if there's a match, create children */
 432         if (of_match_node(matches, root)) {
 433                 rc = of_platform_bus_create(root, matches, NULL, parent, false);
 434         } else for_each_child_of_node(root, child) {
 435                 if (!of_match_node(matches, child))
 436                         continue;
 437                 rc = of_platform_bus_create(child, matches, NULL, parent, false);
 438                 if (rc) {
 439                         of_node_put(child);
 440                         break;
 441                 }
 442         }
 443 
 444         of_node_put(root);
 445         return rc;
 446 }
 447 EXPORT_SYMBOL(of_platform_bus_probe);
 448 
 449 /**
 450  * of_platform_populate() - Populate platform_devices from device tree data
 451  * @root: parent of the first level to probe or NULL for the root of the tree
 452  * @matches: match table, NULL to use the default
 453  * @lookup: auxdata table for matching id and platform_data with device nodes
 454  * @parent: parent to hook devices from, NULL for toplevel
 455  *
 456  * Similar to of_platform_bus_probe(), this function walks the device tree
 457  * and creates devices from nodes.  It differs in that it follows the modern
 458  * convention of requiring all device nodes to have a 'compatible' property,
 459  * and it is suitable for creating devices which are children of the root
 460  * node (of_platform_bus_probe will only create children of the root which
 461  * are selected by the @matches argument).
 462  *
 463  * New board support should be using this function instead of
 464  * of_platform_bus_probe().
 465  *
 466  * Returns 0 on success, < 0 on failure.
 467  */
 468 int of_platform_populate(struct device_node *root,
 469                         const struct of_device_id *matches,
 470                         const struct of_dev_auxdata *lookup,
 471                         struct device *parent)
 472 {
 473         struct device_node *child;
 474         int rc = 0;
 475 
 476         root = root ? of_node_get(root) : of_find_node_by_path("/");
 477         if (!root)
 478                 return -EINVAL;
 479 
 480         pr_debug("%s()\n", __func__);
 481         pr_debug(" starting at: %pOF\n", root);
 482 
 483         for_each_child_of_node(root, child) {
 484                 rc = of_platform_bus_create(child, matches, lookup, parent, true);
 485                 if (rc) {
 486                         of_node_put(child);
 487                         break;
 488                 }
 489         }
 490         of_node_set_flag(root, OF_POPULATED_BUS);
 491 
 492         of_node_put(root);
 493         return rc;
 494 }
 495 EXPORT_SYMBOL_GPL(of_platform_populate);
 496 
 497 int of_platform_default_populate(struct device_node *root,
 498                                  const struct of_dev_auxdata *lookup,
 499                                  struct device *parent)
 500 {
 501         return of_platform_populate(root, of_default_bus_match_table, lookup,
 502                                     parent);
 503 }
 504 EXPORT_SYMBOL_GPL(of_platform_default_populate);
 505 
 506 #ifndef CONFIG_PPC
 507 static const struct of_device_id reserved_mem_matches[] = {
 508         { .compatible = "qcom,rmtfs-mem" },
 509         { .compatible = "qcom,cmd-db" },
 510         { .compatible = "ramoops" },
 511         {}
 512 };
 513 
 514 static int __init of_platform_default_populate_init(void)
 515 {
 516         struct device_node *node;
 517 
 518         if (!of_have_populated_dt())
 519                 return -ENODEV;
 520 
 521         /*
 522          * Handle certain compatibles explicitly, since we don't want to create
 523          * platform_devices for every node in /reserved-memory with a
 524          * "compatible",
 525          */
 526         for_each_matching_node(node, reserved_mem_matches)
 527                 of_platform_device_create(node, NULL, NULL);
 528 
 529         node = of_find_node_by_path("/firmware");
 530         if (node) {
 531                 of_platform_populate(node, NULL, NULL, NULL);
 532                 of_node_put(node);
 533         }
 534 
 535         /* Populate everything else. */
 536         of_platform_default_populate(NULL, NULL, NULL);
 537 
 538         return 0;
 539 }
 540 arch_initcall_sync(of_platform_default_populate_init);
 541 #endif
 542 
 543 int of_platform_device_destroy(struct device *dev, void *data)
 544 {
 545         /* Do not touch devices not populated from the device tree */
 546         if (!dev->of_node || !of_node_check_flag(dev->of_node, OF_POPULATED))
 547                 return 0;
 548 
 549         /* Recurse for any nodes that were treated as busses */
 550         if (of_node_check_flag(dev->of_node, OF_POPULATED_BUS))
 551                 device_for_each_child(dev, NULL, of_platform_device_destroy);
 552 
 553         of_node_clear_flag(dev->of_node, OF_POPULATED);
 554         of_node_clear_flag(dev->of_node, OF_POPULATED_BUS);
 555 
 556         if (dev->bus == &platform_bus_type)
 557                 platform_device_unregister(to_platform_device(dev));
 558 #ifdef CONFIG_ARM_AMBA
 559         else if (dev->bus == &amba_bustype)
 560                 amba_device_unregister(to_amba_device(dev));
 561 #endif
 562 
 563         return 0;
 564 }
 565 EXPORT_SYMBOL_GPL(of_platform_device_destroy);
 566 
 567 /**
 568  * of_platform_depopulate() - Remove devices populated from device tree
 569  * @parent: device which children will be removed
 570  *
 571  * Complementary to of_platform_populate(), this function removes children
 572  * of the given device (and, recurrently, their children) that have been
 573  * created from their respective device tree nodes (and only those,
 574  * leaving others - eg. manually created - unharmed).
 575  */
 576 void of_platform_depopulate(struct device *parent)
 577 {
 578         if (parent->of_node && of_node_check_flag(parent->of_node, OF_POPULATED_BUS)) {
 579                 device_for_each_child(parent, NULL, of_platform_device_destroy);
 580                 of_node_clear_flag(parent->of_node, OF_POPULATED_BUS);
 581         }
 582 }
 583 EXPORT_SYMBOL_GPL(of_platform_depopulate);
 584 
 585 static void devm_of_platform_populate_release(struct device *dev, void *res)
 586 {
 587         of_platform_depopulate(*(struct device **)res);
 588 }
 589 
 590 /**
 591  * devm_of_platform_populate() - Populate platform_devices from device tree data
 592  * @dev: device that requested to populate from device tree data
 593  *
 594  * Similar to of_platform_populate(), but will automatically call
 595  * of_platform_depopulate() when the device is unbound from the bus.
 596  *
 597  * Returns 0 on success, < 0 on failure.
 598  */
 599 int devm_of_platform_populate(struct device *dev)
 600 {
 601         struct device **ptr;
 602         int ret;
 603 
 604         if (!dev)
 605                 return -EINVAL;
 606 
 607         ptr = devres_alloc(devm_of_platform_populate_release,
 608                            sizeof(*ptr), GFP_KERNEL);
 609         if (!ptr)
 610                 return -ENOMEM;
 611 
 612         ret = of_platform_populate(dev->of_node, NULL, NULL, dev);
 613         if (ret) {
 614                 devres_free(ptr);
 615         } else {
 616                 *ptr = dev;
 617                 devres_add(dev, ptr);
 618         }
 619 
 620         return ret;
 621 }
 622 EXPORT_SYMBOL_GPL(devm_of_platform_populate);
 623 
 624 static int devm_of_platform_match(struct device *dev, void *res, void *data)
 625 {
 626         struct device **ptr = res;
 627 
 628         if (!ptr) {
 629                 WARN_ON(!ptr);
 630                 return 0;
 631         }
 632 
 633         return *ptr == data;
 634 }
 635 
 636 /**
 637  * devm_of_platform_depopulate() - Remove devices populated from device tree
 638  * @dev: device that requested to depopulate from device tree data
 639  *
 640  * Complementary to devm_of_platform_populate(), this function removes children
 641  * of the given device (and, recurrently, their children) that have been
 642  * created from their respective device tree nodes (and only those,
 643  * leaving others - eg. manually created - unharmed).
 644  */
 645 void devm_of_platform_depopulate(struct device *dev)
 646 {
 647         int ret;
 648 
 649         ret = devres_release(dev, devm_of_platform_populate_release,
 650                              devm_of_platform_match, dev);
 651 
 652         WARN_ON(ret);
 653 }
 654 EXPORT_SYMBOL_GPL(devm_of_platform_depopulate);
 655 
 656 #ifdef CONFIG_OF_DYNAMIC
 657 static int of_platform_notify(struct notifier_block *nb,
 658                                 unsigned long action, void *arg)
 659 {
 660         struct of_reconfig_data *rd = arg;
 661         struct platform_device *pdev_parent, *pdev;
 662         bool children_left;
 663 
 664         switch (of_reconfig_get_state_change(action, rd)) {
 665         case OF_RECONFIG_CHANGE_ADD:
 666                 /* verify that the parent is a bus */
 667                 if (!of_node_check_flag(rd->dn->parent, OF_POPULATED_BUS))
 668                         return NOTIFY_OK;       /* not for us */
 669 
 670                 /* already populated? (driver using of_populate manually) */
 671                 if (of_node_check_flag(rd->dn, OF_POPULATED))
 672                         return NOTIFY_OK;
 673 
 674                 /* pdev_parent may be NULL when no bus platform device */
 675                 pdev_parent = of_find_device_by_node(rd->dn->parent);
 676                 pdev = of_platform_device_create(rd->dn, NULL,
 677                                 pdev_parent ? &pdev_parent->dev : NULL);
 678                 of_dev_put(pdev_parent);
 679 
 680                 if (pdev == NULL) {
 681                         pr_err("%s: failed to create for '%pOF'\n",
 682                                         __func__, rd->dn);
 683                         /* of_platform_device_create tosses the error code */
 684                         return notifier_from_errno(-EINVAL);
 685                 }
 686                 break;
 687 
 688         case OF_RECONFIG_CHANGE_REMOVE:
 689 
 690                 /* already depopulated? */
 691                 if (!of_node_check_flag(rd->dn, OF_POPULATED))
 692                         return NOTIFY_OK;
 693 
 694                 /* find our device by node */
 695                 pdev = of_find_device_by_node(rd->dn);
 696                 if (pdev == NULL)
 697                         return NOTIFY_OK;       /* no? not meant for us */
 698 
 699                 /* unregister takes one ref away */
 700                 of_platform_device_destroy(&pdev->dev, &children_left);
 701 
 702                 /* and put the reference of the find */
 703                 of_dev_put(pdev);
 704                 break;
 705         }
 706 
 707         return NOTIFY_OK;
 708 }
 709 
 710 static struct notifier_block platform_of_notifier = {
 711         .notifier_call = of_platform_notify,
 712 };
 713 
 714 void of_platform_register_reconfig_notifier(void)
 715 {
 716         WARN_ON(of_reconfig_notifier_register(&platform_of_notifier));
 717 }
 718 #endif /* CONFIG_OF_DYNAMIC */
 719 
 720 #endif /* CONFIG_OF_ADDRESS */