drivers/of/platform.c

   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_irq.h>
  21 #include <linux/of_platform.h>
  22 #include <linux/platform_device.h>
  23
  24 const struct of_device_id of_default_bus_match_table[] = {
  25         { .compatible = "simple-bus", },
  26         { .compatible = "simple-mfd", },
  27         { .compatible = "isa", },
  28 #ifdef CONFIG_ARM_AMBA
  29         { .compatible = "arm,amba-bus", },
  30 #endif /* CONFIG_ARM_AMBA */
  31         {} /* Empty terminated list */
  32 };
  33
  34 static const struct of_device_id of_skipped_node_table[] = {
  35         { .compatible = "operating-points-v2", },
  36         {} /* Empty terminated list */
  37 };
  38
  39 /**
  40  * of_find_device_by_node - Find the platform_device associated with a node
  41  * @np: Pointer to device tree node
  42  *
  43  * Takes a reference to the embedded struct device which needs to be dropped
  44  * after use.
  45  *
  46  * Return: platform_device pointer, or NULL if not found
  47  */
  48 struct platform_device *of_find_device_by_node(struct device_node *np)
  49 {
  50         struct device *dev;
  51
  52         dev = bus_find_device_by_of_node(&platform_bus_type, np);
  53         return dev ? to_platform_device(dev) : NULL;
  54 }
  55 EXPORT_SYMBOL(of_find_device_by_node);
  56
  57 #ifdef CONFIG_OF_ADDRESS
  58 /*
  59  * The following routines scan a subtree and registers a device for
  60  * each applicable node.
  61  *
  62  * Note: sparc doesn't use these routines because it has a different
  63  * mechanism for creating devices from device tree nodes.
  64  */
  65
  66 /**
  67  * of_device_make_bus_id - Use the device node data to assign a unique name
  68  * @dev: pointer to device structure that is linked to a device tree node
  69  *
  70  * This routine will first try using the translated bus address to
  71  * derive a unique name. If it cannot, then it will prepend names from
  72  * parent nodes until a unique name can be derived.
  73  */
  74 static void of_device_make_bus_id(struct device *dev)
  75 {
  76         struct device_node *node = dev->of_node;
  77         const __be32 *reg;
  78         u64 addr;
  79
  80         /* Construct the name, using parent nodes if necessary to ensure uniqueness */
  81         while (node->parent) {
  82                 /*
  83                  * If the address can be translated, then that is as much
  84                  * uniqueness as we need. Make it the first component and return
  85                  */
  86                 reg = of_get_property(node, "reg", NULL);
  87                 if (reg && (addr = of_translate_address(node, reg)) != OF_BAD_ADDR) {
  88                         dev_set_name(dev, dev_name(dev) ? "%llx.%pOFn:%s" : "%llx.%pOFn",
  89                                      addr, node, dev_name(dev));
  90                         return;
  91                 }
  92
  93                 /* format arguments only used if dev_name() resolves to NULL */
  94                 dev_set_name(dev, dev_name(dev) ? "%s:%s" : "%s",
  95                              kbasename(node->full_name), dev_name(dev));
  96                 node = node->parent;
  97         }
  98 }
  99
 100 /**
 101  * of_device_alloc - Allocate and initialize an of_device
 102  * @np: device node to assign to device
 103  * @bus_id: Name to assign to the device.  May be null to use default name.
 104  * @parent: Parent device.
 105  */
 106 struct platform_device *of_device_alloc(struct device_node *np,
 107                                   const char *bus_id,
 108                                   struct device *parent)
 109 {
 110         struct platform_device *dev;
 111         int rc, i, num_reg = 0, num_irq;
 112         struct resource *res, temp_res;
 113
 114         dev = platform_device_alloc("", PLATFORM_DEVID_NONE);
 115         if (!dev)
 116                 return NULL;
 117
 118         /* count the io and irq resources */
 119         while (of_address_to_resource(np, num_reg, &temp_res) == 0)
 120                 num_reg++;
 121         num_irq = of_irq_count(np);
 122
 123         /* Populate the resource table */
 124         if (num_irq || num_reg) {
 125                 res = kcalloc(num_irq + num_reg, sizeof(*res), GFP_KERNEL);
 126                 if (!res) {
 127                         platform_device_put(dev);
 128                         return NULL;
 129                 }
 130
 131                 dev->num_resources = num_reg + num_irq;
 132                 dev->resource = res;
 133                 for (i = 0; i < num_reg; i++, res++) {
 134                         rc = of_address_to_resource(np, i, res);
 135                         WARN_ON(rc);
 136                 }
 137                 if (of_irq_to_resource_table(np, res, num_irq) != num_irq)
 138                         pr_debug("not all legacy IRQ resources mapped for %pOFn\n",
 139                                  np);
 140         }
 141
 142         dev->dev.of_node = of_node_get(np);
 143         dev->dev.fwnode = &np->fwnode;
 144         dev->dev.parent = parent ? : &platform_bus;
 145
 146         if (bus_id)
 147                 dev_set_name(&dev->dev, "%s", bus_id);
 148         else
 149                 of_device_make_bus_id(&dev->dev);
 150
 151         return dev;
 152 }
 153 EXPORT_SYMBOL(of_device_alloc);
 154
 155 /**
 156  * of_platform_device_create_pdata - Alloc, initialize and register an of_device
 157  * @np: pointer to node to create device for
 158  * @bus_id: name to assign device
 159  * @platform_data: pointer to populate platform_data pointer with
 160  * @parent: Linux device model parent device.
 161  *
 162  * Return: Pointer to created platform device, or NULL if a device was not
 163  * registered.  Unavailable devices will not get registered.
 164  */
 165 static struct platform_device *of_platform_device_create_pdata(
 166                                         struct device_node *np,
 167                                         const char *bus_id,
 168                                         void *platform_data,
 169                                         struct device *parent)
 170 {
 171         struct platform_device *dev;
 172
 173         if (!of_device_is_available(np) ||
 174             of_node_test_and_set_flag(np, OF_POPULATED))
 175                 return NULL;
 176
 177         dev = of_device_alloc(np, bus_id, parent);
 178         if (!dev)
 179                 goto err_clear_flag;
 180
 181         dev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
 182         if (!dev->dev.dma_mask)
 183                 dev->dev.dma_mask = &dev->dev.coherent_dma_mask;
 184         dev->dev.bus = &platform_bus_type;
 185         dev->dev.platform_data = platform_data;
 186         of_msi_configure(&dev->dev, dev->dev.of_node);
 187
 188         if (of_device_add(dev) != 0) {
 189                 platform_device_put(dev);
 190                 goto err_clear_flag;
 191         }
 192
 193         return dev;
 194
 195 err_clear_flag:
 196         of_node_clear_flag(np, OF_POPULATED);
 197         return NULL;
 198 }
 199
 200 /**
 201  * of_platform_device_create - Alloc, initialize and register an of_device
 202  * @np: pointer to node to create device for
 203  * @bus_id: name to assign device
 204  * @parent: Linux device model parent device.
 205  *
 206  * Return: Pointer to created platform device, or NULL if a device was not
 207  * registered.  Unavailable devices will not get registered.
 208  */
 209 struct platform_device *of_platform_device_create(struct device_node *np,
 210                                             const char *bus_id,
 211                                             struct device *parent)
 212 {
 213         return of_platform_device_create_pdata(np, bus_id, NULL, parent);
 214 }
 215 EXPORT_SYMBOL(of_platform_device_create);
 216
 217 #ifdef CONFIG_ARM_AMBA
 218 static struct amba_device *of_amba_device_create(struct device_node *node,
 219                                                  const char *bus_id,
 220                                                  void *platform_data,
 221                                                  struct device *parent)
 222 {
 223         struct amba_device *dev;
 224         const void *prop;
 225         int i, ret;
 226
 227         pr_debug("Creating amba device %pOF\n", node);
 228
 229         if (!of_device_is_available(node) ||
 230             of_node_test_and_set_flag(node, OF_POPULATED))
 231                 return NULL;
 232
 233         dev = amba_device_alloc(NULL, 0, 0);
 234         if (!dev)
 235                 goto err_clear_flag;
 236
 237         /* AMBA devices only support a single DMA mask */
 238         dev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
 239         dev->dev.dma_mask = &dev->dev.coherent_dma_mask;
 240
 241         /* setup generic device info */
 242         dev->dev.of_node = of_node_get(node);
 243         dev->dev.fwnode = &node->fwnode;
 244         dev->dev.parent = parent ? : &platform_bus;
 245         dev->dev.platform_data = platform_data;
 246         if (bus_id)
 247                 dev_set_name(&dev->dev, "%s", bus_id);
 248         else
 249                 of_device_make_bus_id(&dev->dev);
 250
 251         /* Allow the HW Peripheral ID to be overridden */
 252         prop = of_get_property(node, "arm,primecell-periphid", NULL);
 253         if (prop)
 254                 dev->periphid = of_read_ulong(prop, 1);
 255
 256         /* Decode the IRQs and address ranges */
 257         for (i = 0; i < AMBA_NR_IRQS; i++)
 258                 dev->irq[i] = irq_of_parse_and_map(node, i);
 259
 260         ret = of_address_to_resource(node, 0, &dev->res);
 261         if (ret) {
 262                 pr_err("amba: of_address_to_resource() failed (%d) for %pOF\n",
 263                        ret, node);
 264                 goto err_free;
 265         }
 266
 267         ret = amba_device_add(dev, &iomem_resource);
 268         if (ret) {
 269                 pr_err("amba_device_add() failed (%d) for %pOF\n",
 270                        ret, node);
 271                 goto err_free;
 272         }
 273
 274         return dev;
 275
 276 err_free:
 277         amba_device_put(dev);
 278 err_clear_flag:
 279         of_node_clear_flag(node, OF_POPULATED);
 280         return NULL;
 281 }
 282 #else /* CONFIG_ARM_AMBA */
 283 static struct amba_device *of_amba_device_create(struct device_node *node,
 284                                                  const char *bus_id,
 285                                                  void *platform_data,
 286                                                  struct device *parent)
 287 {
 288         return NULL;
 289 }
 290 #endif /* CONFIG_ARM_AMBA */
 291
 292 /*
 293  * of_dev_lookup() - Given a device node, lookup the preferred Linux name
 294  */
 295 static const struct of_dev_auxdata *of_dev_lookup(const struct of_dev_auxdata *lookup,
 296                                  struct device_node *np)
 297 {
 298         const struct of_dev_auxdata *auxdata;
 299         struct resource res;
 300         int compatible = 0;
 301
 302         if (!lookup)
 303                 return NULL;
 304
 305         auxdata = lookup;
 306         for (; auxdata->compatible; auxdata++) {
 307                 if (!of_device_is_compatible(np, auxdata->compatible))
 308                         continue;
 309                 compatible++;
 310                 if (!of_address_to_resource(np, 0, &res))
 311                         if (res.start != auxdata->phys_addr)
 312                                 continue;
 313                 pr_debug("%pOF: devname=%s\n", np, auxdata->name);
 314                 return auxdata;
 315         }
 316
 317         if (!compatible)
 318                 return NULL;
 319
 320         /* Try compatible match if no phys_addr and name are specified */
 321         auxdata = lookup;
 322         for (; auxdata->compatible; auxdata++) {
 323                 if (!of_device_is_compatible(np, auxdata->compatible))
 324                         continue;
 325                 if (!auxdata->phys_addr && !auxdata->name) {
 326                         pr_debug("%pOF: compatible match\n", np);
 327                         return auxdata;
 328                 }
 329         }
 330
 331         return NULL;
 332 }
 333
 334 /**
 335  * of_platform_bus_create() - Create a device for a node and its children.
 336  * @bus: device node of the bus to instantiate
 337  * @matches: match table for bus nodes
 338  * @lookup: auxdata table for matching id and platform_data with device nodes
 339  * @parent: parent for new device, or NULL for top level.
 340  * @strict: require compatible property
 341  *
 342  * Creates a platform_device for the provided device_node, and optionally
 343  * recursively create devices for all the child nodes.
 344  */
 345 static int of_platform_bus_create(struct device_node *bus,
 346                                   const struct of_device_id *matches,
 347                                   const struct of_dev_auxdata *lookup,
 348                                   struct device *parent, bool strict)
 349 {
 350         const struct of_dev_auxdata *auxdata;
 351         struct device_node *child;
 352         struct platform_device *dev;
 353         const char *bus_id = NULL;
 354         void *platform_data = NULL;
 355         int rc = 0;
 356
 357         /* Make sure it has a compatible property */
 358         if (strict && (!of_get_property(bus, "compatible", NULL))) {
 359                 pr_debug("%s() - skipping %pOF, no compatible prop\n",
 360                          __func__, bus);
 361                 return 0;
 362         }
 363
 364         /* Skip nodes for which we don't want to create devices */
 365         if (unlikely(of_match_node(of_skipped_node_table, bus))) {
 366                 pr_debug("%s() - skipping %pOF node\n", __func__, bus);
 367                 return 0;
 368         }
 369
 370         if (of_node_check_flag(bus, OF_POPULATED_BUS)) {
 371                 pr_debug("%s() - skipping %pOF, already populated\n",
 372                         __func__, bus);
 373                 return 0;
 374         }
 375
 376         auxdata = of_dev_lookup(lookup, bus);
 377         if (auxdata) {
 378                 bus_id = auxdata->name;
 379                 platform_data = auxdata->platform_data;
 380         }
 381
 382         if (of_device_is_compatible(bus, "arm,primecell")) {
 383                 /*
 384                  * Don't return an error here to keep compatibility with older
 385                  * device tree files.
 386                  */
 387                 of_amba_device_create(bus, bus_id, platform_data, parent);
 388                 return 0;
 389         }
 390
 391         dev = of_platform_device_create_pdata(bus, bus_id, platform_data, parent);
 392         if (!dev || !of_match_node(matches, bus))
 393                 return 0;
 394
 395         for_each_child_of_node(bus, child) {
 396                 pr_debug("   create child: %pOF\n", child);
 397                 rc = of_platform_bus_create(child, matches, lookup, &dev->dev, strict);
 398                 if (rc) {
 399                         of_node_put(child);
 400                         break;
 401                 }
 402         }
 403         of_node_set_flag(bus, OF_POPULATED_BUS);
 404         return rc;
 405 }
 406
 407 /**
 408  * of_platform_bus_probe() - Probe the device-tree for platform buses
 409  * @root: parent of the first level to probe or NULL for the root of the tree
 410  * @matches: match table for bus nodes
 411  * @parent: parent to hook devices from, NULL for toplevel
 412  *
 413  * Note that children of the provided root are not instantiated as devices
 414  * unless the specified root itself matches the bus list and is not NULL.
 415  */
 416 int of_platform_bus_probe(struct device_node *root,
 417                           const struct of_device_id *matches,
 418                           struct device *parent)
 419 {
 420         struct device_node *child;
 421         int rc = 0;
 422
 423         root = root ? of_node_get(root) : of_find_node_by_path("/");
 424         if (!root)
 425                 return -EINVAL;
 426
 427         pr_debug("%s()\n", __func__);
 428         pr_debug(" starting at: %pOF\n", root);
 429
 430         /* Do a self check of bus type, if there's a match, create children */
 431         if (of_match_node(matches, root)) {
 432                 rc = of_platform_bus_create(root, matches, NULL, parent, false);
 433         } else for_each_child_of_node(root, child) {
 434                 if (!of_match_node(matches, child))
 435                         continue;
 436                 rc = of_platform_bus_create(child, matches, NULL, parent, false);
 437                 if (rc) {
 438                         of_node_put(child);
 439                         break;
 440                 }
 441         }
 442
 443         of_node_put(root);
 444         return rc;
 445 }
 446 EXPORT_SYMBOL(of_platform_bus_probe);
 447
 448 /**
 449  * of_platform_populate() - Populate platform_devices from device tree data
 450  * @root: parent of the first level to probe or NULL for the root of the tree
 451  * @matches: match table, NULL to use the default
 452  * @lookup: auxdata table for matching id and platform_data with device nodes
 453  * @parent: parent to hook devices from, NULL for toplevel
 454  *
 455  * Similar to of_platform_bus_probe(), this function walks the device tree
 456  * and creates devices from nodes.  It differs in that it follows the modern
 457  * convention of requiring all device nodes to have a 'compatible' property,
 458  * and it is suitable for creating devices which are children of the root
 459  * node (of_platform_bus_probe will only create children of the root which
 460  * are selected by the @matches argument).
 461  *
 462  * New board support should be using this function instead of
 463  * of_platform_bus_probe().
 464  *
 465  * Return: 0 on success, < 0 on failure.
 466  */
 467 int of_platform_populate(struct device_node *root,
 468                         const struct of_device_id *matches,
 469                         const struct of_dev_auxdata *lookup,
 470                         struct device *parent)
 471 {
 472         struct device_node *child;
 473         int rc = 0;
 474
 475         root = root ? of_node_get(root) : of_find_node_by_path("/");
 476         if (!root)
 477                 return -EINVAL;
 478
 479         pr_debug("%s()\n", __func__);
 480         pr_debug(" starting at: %pOF\n", root);
 481
 482         device_links_supplier_sync_state_pause();
 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         device_links_supplier_sync_state_resume();
 491
 492         of_node_set_flag(root, OF_POPULATED_BUS);
 493
 494         of_node_put(root);
 495         return rc;
 496 }
 497 EXPORT_SYMBOL_GPL(of_platform_populate);
 498
 499 int of_platform_default_populate(struct device_node *root,
 500                                  const struct of_dev_auxdata *lookup,
 501                                  struct device *parent)
 502 {
 503         return of_platform_populate(root, of_default_bus_match_table, lookup,
 504                                     parent);
 505 }
 506 EXPORT_SYMBOL_GPL(of_platform_default_populate);
 507
 508 #ifndef CONFIG_PPC
 509 static const struct of_device_id reserved_mem_matches[] = {
 510         { .compatible = "qcom,rmtfs-mem" },
 511         { .compatible = "qcom,cmd-db" },
 512         { .compatible = "ramoops" },
 513         { .compatible = "nvmem-rmem" },
 514         {}
 515 };
 516
 517 static int __init of_platform_default_populate_init(void)
 518 {
 519         struct device_node *node;
 520
 521         device_links_supplier_sync_state_pause();
 522
 523         if (!of_have_populated_dt())
 524                 return -ENODEV;
 525
 526         /*
 527          * Handle certain compatibles explicitly, since we don't want to create
 528          * platform_devices for every node in /reserved-memory with a
 529          * "compatible",
 530          */
 531         for_each_matching_node(node, reserved_mem_matches)
 532                 of_platform_device_create(node, NULL, NULL);
 533
 534         node = of_find_node_by_path("/firmware");
 535         if (node) {
 536                 of_platform_populate(node, NULL, NULL, NULL);
 537                 of_node_put(node);
 538         }
 539
 540         /* Populate everything else. */
 541         of_platform_default_populate(NULL, NULL, NULL);
 542
 543         return 0;
 544 }
 545 arch_initcall_sync(of_platform_default_populate_init);
 546
 547 static int __init of_platform_sync_state_init(void)
 548 {
 549         device_links_supplier_sync_state_resume();
 550         return 0;
 551 }
 552 late_initcall_sync(of_platform_sync_state_init);
 553 #endif
 554
 555 int of_platform_device_destroy(struct device *dev, void *data)
 556 {
 557         /* Do not touch devices not populated from the device tree */
 558         if (!dev->of_node || !of_node_check_flag(dev->of_node, OF_POPULATED))
 559                 return 0;
 560
 561         /* Recurse for any nodes that were treated as busses */
 562         if (of_node_check_flag(dev->of_node, OF_POPULATED_BUS))
 563                 device_for_each_child(dev, NULL, of_platform_device_destroy);
 564
 565         of_node_clear_flag(dev->of_node, OF_POPULATED);
 566         of_node_clear_flag(dev->of_node, OF_POPULATED_BUS);
 567
 568         if (dev->bus == &platform_bus_type)
 569                 platform_device_unregister(to_platform_device(dev));
 570 #ifdef CONFIG_ARM_AMBA
 571         else if (dev->bus == &amba_bustype)
 572                 amba_device_unregister(to_amba_device(dev));
 573 #endif
 574
 575         return 0;
 576 }
 577 EXPORT_SYMBOL_GPL(of_platform_device_destroy);
 578
 579 /**
 580  * of_platform_depopulate() - Remove devices populated from device tree
 581  * @parent: device which children will be removed
 582  *
 583  * Complementary to of_platform_populate(), this function removes children
 584  * of the given device (and, recurrently, their children) that have been
 585  * created from their respective device tree nodes (and only those,
 586  * leaving others - eg. manually created - unharmed).
 587  */
 588 void of_platform_depopulate(struct device *parent)
 589 {
 590         if (parent->of_node && of_node_check_flag(parent->of_node, OF_POPULATED_BUS)) {
 591                 device_for_each_child_reverse(parent, NULL, of_platform_device_destroy);
 592                 of_node_clear_flag(parent->of_node, OF_POPULATED_BUS);
 593         }
 594 }
 595 EXPORT_SYMBOL_GPL(of_platform_depopulate);
 596
 597 static void devm_of_platform_populate_release(struct device *dev, void *res)
 598 {
 599         of_platform_depopulate(*(struct device **)res);
 600 }
 601
 602 /**
 603  * devm_of_platform_populate() - Populate platform_devices from device tree data
 604  * @dev: device that requested to populate from device tree data
 605  *
 606  * Similar to of_platform_populate(), but will automatically call
 607  * of_platform_depopulate() when the device is unbound from the bus.
 608  *
 609  * Return: 0 on success, < 0 on failure.
 610  */
 611 int devm_of_platform_populate(struct device *dev)
 612 {
 613         struct device **ptr;
 614         int ret;
 615
 616         if (!dev)
 617                 return -EINVAL;
 618
 619         ptr = devres_alloc(devm_of_platform_populate_release,
 620                            sizeof(*ptr), GFP_KERNEL);
 621         if (!ptr)
 622                 return -ENOMEM;
 623
 624         ret = of_platform_populate(dev->of_node, NULL, NULL, dev);
 625         if (ret) {
 626                 devres_free(ptr);
 627         } else {
 628                 *ptr = dev;
 629                 devres_add(dev, ptr);
 630         }
 631
 632         return ret;
 633 }
 634 EXPORT_SYMBOL_GPL(devm_of_platform_populate);
 635
 636 static int devm_of_platform_match(struct device *dev, void *res, void *data)
 637 {
 638         struct device **ptr = res;
 639
 640         if (!ptr) {
 641                 WARN_ON(!ptr);
 642                 return 0;
 643         }
 644
 645         return *ptr == data;
 646 }
 647
 648 /**
 649  * devm_of_platform_depopulate() - Remove devices populated from device tree
 650  * @dev: device that requested to depopulate from device tree data
 651  *
 652  * Complementary to devm_of_platform_populate(), this function removes children
 653  * of the given device (and, recurrently, their children) that have been
 654  * created from their respective device tree nodes (and only those,
 655  * leaving others - eg. manually created - unharmed).
 656  */
 657 void devm_of_platform_depopulate(struct device *dev)
 658 {
 659         int ret;
 660
 661         ret = devres_release(dev, devm_of_platform_populate_release,
 662                              devm_of_platform_match, dev);
 663
 664         WARN_ON(ret);
 665 }
 666 EXPORT_SYMBOL_GPL(devm_of_platform_depopulate);
 667
 668 #ifdef CONFIG_OF_DYNAMIC
 669 static int of_platform_notify(struct notifier_block *nb,
 670                                 unsigned long action, void *arg)
 671 {
 672         struct of_reconfig_data *rd = arg;
 673         struct platform_device *pdev_parent, *pdev;
 674         bool children_left;
 675
 676         switch (of_reconfig_get_state_change(action, rd)) {
 677         case OF_RECONFIG_CHANGE_ADD:
 678                 /* verify that the parent is a bus */
 679                 if (!of_node_check_flag(rd->dn->parent, OF_POPULATED_BUS))
 680                         return NOTIFY_OK;       /* not for us */
 681
 682                 /* already populated? (driver using of_populate manually) */
 683                 if (of_node_check_flag(rd->dn, OF_POPULATED))
 684                         return NOTIFY_OK;
 685
 686                 /* pdev_parent may be NULL when no bus platform device */
 687                 pdev_parent = of_find_device_by_node(rd->dn->parent);
 688                 pdev = of_platform_device_create(rd->dn, NULL,
 689                                 pdev_parent ? &pdev_parent->dev : NULL);
 690                 platform_device_put(pdev_parent);
 691
 692                 if (pdev == NULL) {
 693                         pr_err("%s: failed to create for '%pOF'\n",
 694                                         __func__, rd->dn);
 695                         /* of_platform_device_create tosses the error code */
 696                         return notifier_from_errno(-EINVAL);
 697                 }
 698                 break;
 699
 700         case OF_RECONFIG_CHANGE_REMOVE:
 701
 702                 /* already depopulated? */
 703                 if (!of_node_check_flag(rd->dn, OF_POPULATED))
 704                         return NOTIFY_OK;
 705
 706                 /* find our device by node */
 707                 pdev = of_find_device_by_node(rd->dn);
 708                 if (pdev == NULL)
 709                         return NOTIFY_OK;       /* no? not meant for us */
 710
 711                 /* unregister takes one ref away */
 712                 of_platform_device_destroy(&pdev->dev, &children_left);
 713
 714                 /* and put the reference of the find */
 715                 platform_device_put(pdev);
 716                 break;
 717         }
 718
 719         return NOTIFY_OK;
 720 }
 721
 722 static struct notifier_block platform_of_notifier = {
 723         .notifier_call = of_platform_notify,
 724 };
 725
 726 void of_platform_register_reconfig_notifier(void)
 727 {
 728         WARN_ON(of_reconfig_notifier_register(&platform_of_notifier));
 729 }
 730 #endif /* CONFIG_OF_DYNAMIC */
 731
 732 #endif /* CONFIG_OF_ADDRESS */