drivers/of/platform.c

   1 /*
   2  *    Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corp.
   3  *                       <benh@kernel.crashing.org>
   4  *    and                Arnd Bergmann, IBM Corp.
   5  *    Merged from powerpc/kernel/of_platform.c and
   6  *    sparc{,64}/kernel/of_device.c by Stephen Rothwell
   7  *
   8  *  This program is free software; you can redistribute it and/or
   9  *  modify it under the terms of the GNU General Public License
  10  *  as published by the Free Software Foundation; either version
  11  *  2 of the License, or (at your option) any later version.
  12  *
  13  */
  14 #include <linux/errno.h>
  15 #include <linux/module.h>
  16 #include <linux/device.h>
  17 #include <linux/dma-mapping.h>
  18 #include <linux/slab.h>
  19 #include <linux/of_address.h>
  20 #include <linux/of_device.h>
  21 #include <linux/of_irq.h>
  22 #include <linux/of_platform.h>
  23 #include <linux/platform_device.h>
  24
  25 static int of_dev_node_match(struct device *dev, void *data)
  26 {
  27         return dev->of_node == data;
  28 }
  29
  30 /**
  31  * of_find_device_by_node - Find the platform_device associated with a node
  32  * @np: Pointer to device tree node
  33  *
  34  * Returns platform_device pointer, or NULL if not found
  35  */
  36 struct platform_device *of_find_device_by_node(struct device_node *np)
  37 {
  38         struct device *dev;
  39
  40         dev = bus_find_device(&platform_bus_type, NULL, np, of_dev_node_match);
  41         return dev ? to_platform_device(dev) : NULL;
  42 }
  43 EXPORT_SYMBOL(of_find_device_by_node);
  44
  45 static int platform_driver_probe_shim(struct platform_device *pdev)
  46 {
  47         struct platform_driver *pdrv;
  48         struct of_platform_driver *ofpdrv;
  49         const struct of_device_id *match;
  50
  51         pdrv = container_of(pdev->dev.driver, struct platform_driver, driver);
  52         ofpdrv = container_of(pdrv, struct of_platform_driver, platform_driver);
  53
  54         /* There is an unlikely chance that an of_platform driver might match
  55          * on a non-OF platform device.  If so, then of_match_device() will
  56          * come up empty.  Return -EINVAL in this case so other drivers get
  57          * the chance to bind. */
  58         match = of_match_device(pdev->dev.driver->of_match_table, &pdev->dev);
  59         return match ? ofpdrv->probe(pdev, match) : -EINVAL;
  60 }
  61
  62 static void platform_driver_shutdown_shim(struct platform_device *pdev)
  63 {
  64         struct platform_driver *pdrv;
  65         struct of_platform_driver *ofpdrv;
  66
  67         pdrv = container_of(pdev->dev.driver, struct platform_driver, driver);
  68         ofpdrv = container_of(pdrv, struct of_platform_driver, platform_driver);
  69         ofpdrv->shutdown(pdev);
  70 }
  71
  72 /**
  73  * of_register_platform_driver
  74  */
  75 int of_register_platform_driver(struct of_platform_driver *drv)
  76 {
  77         char *of_name;
  78
  79         /* setup of_platform_driver to platform_driver adaptors */
  80         drv->platform_driver.driver = drv->driver;
  81
  82         /* Prefix the driver name with 'of:' to avoid namespace collisions
  83          * and bogus matches.  There are some drivers in the tree that
  84          * register both an of_platform_driver and a platform_driver with
  85          * the same name.  This is a temporary measure until they are all
  86          * cleaned up --gcl July 29, 2010 */
  87         of_name = kmalloc(strlen(drv->driver.name) + 5, GFP_KERNEL);
  88         if (!of_name)
  89                 return -ENOMEM;
  90         sprintf(of_name, "of:%s", drv->driver.name);
  91         drv->platform_driver.driver.name = of_name;
  92
  93         if (drv->probe)
  94                 drv->platform_driver.probe = platform_driver_probe_shim;
  95         drv->platform_driver.remove = drv->remove;
  96         if (drv->shutdown)
  97                 drv->platform_driver.shutdown = platform_driver_shutdown_shim;
  98         drv->platform_driver.suspend = drv->suspend;
  99         drv->platform_driver.resume = drv->resume;
 100
 101         return platform_driver_register(&drv->platform_driver);
 102 }
 103 EXPORT_SYMBOL(of_register_platform_driver);
 104
 105 void of_unregister_platform_driver(struct of_platform_driver *drv)
 106 {
 107         platform_driver_unregister(&drv->platform_driver);
 108         kfree(drv->platform_driver.driver.name);
 109         drv->platform_driver.driver.name = NULL;
 110 }
 111 EXPORT_SYMBOL(of_unregister_platform_driver);
 112
 113 #if defined(CONFIG_PPC_DCR)
 114 #include <asm/dcr.h>
 115 #endif
 116
 117 extern struct device_attribute of_platform_device_attrs[];
 118
 119 static int of_platform_bus_match(struct device *dev, struct device_driver *drv)
 120 {
 121         const struct of_device_id *matches = drv->of_match_table;
 122
 123         if (!matches)
 124                 return 0;
 125
 126         return of_match_device(matches, dev) != NULL;
 127 }
 128
 129 static int of_platform_device_probe(struct device *dev)
 130 {
 131         int error = -ENODEV;
 132         struct of_platform_driver *drv;
 133         struct platform_device *of_dev;
 134         const struct of_device_id *match;
 135
 136         drv = to_of_platform_driver(dev->driver);
 137         of_dev = to_platform_device(dev);
 138
 139         if (!drv->probe)
 140                 return error;
 141
 142         of_dev_get(of_dev);
 143
 144         match = of_match_device(drv->driver.of_match_table, dev);
 145         if (match)
 146                 error = drv->probe(of_dev, match);
 147         if (error)
 148                 of_dev_put(of_dev);
 149
 150         return error;
 151 }
 152
 153 static int of_platform_device_remove(struct device *dev)
 154 {
 155         struct platform_device *of_dev = to_platform_device(dev);
 156         struct of_platform_driver *drv = to_of_platform_driver(dev->driver);
 157
 158         if (dev->driver && drv->remove)
 159                 drv->remove(of_dev);
 160         return 0;
 161 }
 162
 163 static void of_platform_device_shutdown(struct device *dev)
 164 {
 165         struct platform_device *of_dev = to_platform_device(dev);
 166         struct of_platform_driver *drv = to_of_platform_driver(dev->driver);
 167
 168         if (dev->driver && drv->shutdown)
 169                 drv->shutdown(of_dev);
 170 }
 171
 172 #ifdef CONFIG_PM_SLEEP
 173
 174 static int of_platform_legacy_suspend(struct device *dev, pm_message_t mesg)
 175 {
 176         struct platform_device *of_dev = to_platform_device(dev);
 177         struct of_platform_driver *drv = to_of_platform_driver(dev->driver);
 178         int ret = 0;
 179
 180         if (dev->driver && drv->suspend)
 181                 ret = drv->suspend(of_dev, mesg);
 182         return ret;
 183 }
 184
 185 static int of_platform_legacy_resume(struct device *dev)
 186 {
 187         struct platform_device *of_dev = to_platform_device(dev);
 188         struct of_platform_driver *drv = to_of_platform_driver(dev->driver);
 189         int ret = 0;
 190
 191         if (dev->driver && drv->resume)
 192                 ret = drv->resume(of_dev);
 193         return ret;
 194 }
 195
 196 static int of_platform_pm_prepare(struct device *dev)
 197 {
 198         struct device_driver *drv = dev->driver;
 199         int ret = 0;
 200
 201         if (drv && drv->pm && drv->pm->prepare)
 202                 ret = drv->pm->prepare(dev);
 203
 204         return ret;
 205 }
 206
 207 static void of_platform_pm_complete(struct device *dev)
 208 {
 209         struct device_driver *drv = dev->driver;
 210
 211         if (drv && drv->pm && drv->pm->complete)
 212                 drv->pm->complete(dev);
 213 }
 214
 215 #ifdef CONFIG_SUSPEND
 216
 217 static int of_platform_pm_suspend(struct device *dev)
 218 {
 219         struct device_driver *drv = dev->driver;
 220         int ret = 0;
 221
 222         if (!drv)
 223                 return 0;
 224
 225         if (drv->pm) {
 226                 if (drv->pm->suspend)
 227                         ret = drv->pm->suspend(dev);
 228         } else {
 229                 ret = of_platform_legacy_suspend(dev, PMSG_SUSPEND);
 230         }
 231
 232         return ret;
 233 }
 234
 235 static int of_platform_pm_suspend_noirq(struct device *dev)
 236 {
 237         struct device_driver *drv = dev->driver;
 238         int ret = 0;
 239
 240         if (!drv)
 241                 return 0;
 242
 243         if (drv->pm) {
 244                 if (drv->pm->suspend_noirq)
 245                         ret = drv->pm->suspend_noirq(dev);
 246         }
 247
 248         return ret;
 249 }
 250
 251 static int of_platform_pm_resume(struct device *dev)
 252 {
 253         struct device_driver *drv = dev->driver;
 254         int ret = 0;
 255
 256         if (!drv)
 257                 return 0;
 258
 259         if (drv->pm) {
 260                 if (drv->pm->resume)
 261                         ret = drv->pm->resume(dev);
 262         } else {
 263                 ret = of_platform_legacy_resume(dev);
 264         }
 265
 266         return ret;
 267 }
 268
 269 static int of_platform_pm_resume_noirq(struct device *dev)
 270 {
 271         struct device_driver *drv = dev->driver;
 272         int ret = 0;
 273
 274         if (!drv)
 275                 return 0;
 276
 277         if (drv->pm) {
 278                 if (drv->pm->resume_noirq)
 279                         ret = drv->pm->resume_noirq(dev);
 280         }
 281
 282         return ret;
 283 }
 284
 285 #else /* !CONFIG_SUSPEND */
 286
 287 #define of_platform_pm_suspend          NULL
 288 #define of_platform_pm_resume           NULL
 289 #define of_platform_pm_suspend_noirq    NULL
 290 #define of_platform_pm_resume_noirq     NULL
 291
 292 #endif /* !CONFIG_SUSPEND */
 293
 294 #ifdef CONFIG_HIBERNATION
 295
 296 static int of_platform_pm_freeze(struct device *dev)
 297 {
 298         struct device_driver *drv = dev->driver;
 299         int ret = 0;
 300
 301         if (!drv)
 302                 return 0;
 303
 304         if (drv->pm) {
 305                 if (drv->pm->freeze)
 306                         ret = drv->pm->freeze(dev);
 307         } else {
 308                 ret = of_platform_legacy_suspend(dev, PMSG_FREEZE);
 309         }
 310
 311         return ret;
 312 }
 313
 314 static int of_platform_pm_freeze_noirq(struct device *dev)
 315 {
 316         struct device_driver *drv = dev->driver;
 317         int ret = 0;
 318
 319         if (!drv)
 320                 return 0;
 321
 322         if (drv->pm) {
 323                 if (drv->pm->freeze_noirq)
 324                         ret = drv->pm->freeze_noirq(dev);
 325         }
 326
 327         return ret;
 328 }
 329
 330 static int of_platform_pm_thaw(struct device *dev)
 331 {
 332         struct device_driver *drv = dev->driver;
 333         int ret = 0;
 334
 335         if (!drv)
 336                 return 0;
 337
 338         if (drv->pm) {
 339                 if (drv->pm->thaw)
 340                         ret = drv->pm->thaw(dev);
 341         } else {
 342                 ret = of_platform_legacy_resume(dev);
 343         }
 344
 345         return ret;
 346 }
 347
 348 static int of_platform_pm_thaw_noirq(struct device *dev)
 349 {
 350         struct device_driver *drv = dev->driver;
 351         int ret = 0;
 352
 353         if (!drv)
 354                 return 0;
 355
 356         if (drv->pm) {
 357                 if (drv->pm->thaw_noirq)
 358                         ret = drv->pm->thaw_noirq(dev);
 359         }
 360
 361         return ret;
 362 }
 363
 364 static int of_platform_pm_poweroff(struct device *dev)
 365 {
 366         struct device_driver *drv = dev->driver;
 367         int ret = 0;
 368
 369         if (!drv)
 370                 return 0;
 371
 372         if (drv->pm) {
 373                 if (drv->pm->poweroff)
 374                         ret = drv->pm->poweroff(dev);
 375         } else {
 376                 ret = of_platform_legacy_suspend(dev, PMSG_HIBERNATE);
 377         }
 378
 379         return ret;
 380 }
 381
 382 static int of_platform_pm_poweroff_noirq(struct device *dev)
 383 {
 384         struct device_driver *drv = dev->driver;
 385         int ret = 0;
 386
 387         if (!drv)
 388                 return 0;
 389
 390         if (drv->pm) {
 391                 if (drv->pm->poweroff_noirq)
 392                         ret = drv->pm->poweroff_noirq(dev);
 393         }
 394
 395         return ret;
 396 }
 397
 398 static int of_platform_pm_restore(struct device *dev)
 399 {
 400         struct device_driver *drv = dev->driver;
 401         int ret = 0;
 402
 403         if (!drv)
 404                 return 0;
 405
 406         if (drv->pm) {
 407                 if (drv->pm->restore)
 408                         ret = drv->pm->restore(dev);
 409         } else {
 410                 ret = of_platform_legacy_resume(dev);
 411         }
 412
 413         return ret;
 414 }
 415
 416 static int of_platform_pm_restore_noirq(struct device *dev)
 417 {
 418         struct device_driver *drv = dev->driver;
 419         int ret = 0;
 420
 421         if (!drv)
 422                 return 0;
 423
 424         if (drv->pm) {
 425                 if (drv->pm->restore_noirq)
 426                         ret = drv->pm->restore_noirq(dev);
 427         }
 428
 429         return ret;
 430 }
 431
 432 #else /* !CONFIG_HIBERNATION */
 433
 434 #define of_platform_pm_freeze           NULL
 435 #define of_platform_pm_thaw             NULL
 436 #define of_platform_pm_poweroff         NULL
 437 #define of_platform_pm_restore          NULL
 438 #define of_platform_pm_freeze_noirq     NULL
 439 #define of_platform_pm_thaw_noirq               NULL
 440 #define of_platform_pm_poweroff_noirq   NULL
 441 #define of_platform_pm_restore_noirq    NULL
 442
 443 #endif /* !CONFIG_HIBERNATION */
 444
 445 static struct dev_pm_ops of_platform_dev_pm_ops = {
 446         .prepare = of_platform_pm_prepare,
 447         .complete = of_platform_pm_complete,
 448         .suspend = of_platform_pm_suspend,
 449         .resume = of_platform_pm_resume,
 450         .freeze = of_platform_pm_freeze,
 451         .thaw = of_platform_pm_thaw,
 452         .poweroff = of_platform_pm_poweroff,
 453         .restore = of_platform_pm_restore,
 454         .suspend_noirq = of_platform_pm_suspend_noirq,
 455         .resume_noirq = of_platform_pm_resume_noirq,
 456         .freeze_noirq = of_platform_pm_freeze_noirq,
 457         .thaw_noirq = of_platform_pm_thaw_noirq,
 458         .poweroff_noirq = of_platform_pm_poweroff_noirq,
 459         .restore_noirq = of_platform_pm_restore_noirq,
 460 };
 461
 462 #define OF_PLATFORM_PM_OPS_PTR  (&of_platform_dev_pm_ops)
 463
 464 #else /* !CONFIG_PM_SLEEP */
 465
 466 #define OF_PLATFORM_PM_OPS_PTR  NULL
 467
 468 #endif /* !CONFIG_PM_SLEEP */
 469
 470 int of_bus_type_init(struct bus_type *bus, const char *name)
 471 {
 472         bus->name = name;
 473         bus->match = of_platform_bus_match;
 474         bus->probe = of_platform_device_probe;
 475         bus->remove = of_platform_device_remove;
 476         bus->shutdown = of_platform_device_shutdown;
 477         bus->dev_attrs = of_platform_device_attrs;
 478         bus->pm = OF_PLATFORM_PM_OPS_PTR;
 479         return bus_register(bus);
 480 }
 481
 482 int of_register_driver(struct of_platform_driver *drv, struct bus_type *bus)
 483 {
 484         /*
 485          * Temporary: of_platform_bus used to be distinct from the platform
 486          * bus.  It isn't anymore, and so drivers on the platform bus need
 487          * to be registered in a special way.
 488          *
 489          * After all of_platform_bus_type drivers are converted to
 490          * platform_drivers, this exception can be removed.
 491          */
 492         if (bus == &platform_bus_type)
 493                 return of_register_platform_driver(drv);
 494
 495         /* register with core */
 496         drv->driver.bus = bus;
 497         return driver_register(&drv->driver);
 498 }
 499 EXPORT_SYMBOL(of_register_driver);
 500
 501 void of_unregister_driver(struct of_platform_driver *drv)
 502 {
 503         if (drv->driver.bus == &platform_bus_type)
 504                 of_unregister_platform_driver(drv);
 505         else
 506                 driver_unregister(&drv->driver);
 507 }
 508 EXPORT_SYMBOL(of_unregister_driver);
 509
 510 #if !defined(CONFIG_SPARC)
 511 /*
 512  * The following routines scan a subtree and registers a device for
 513  * each applicable node.
 514  *
 515  * Note: sparc doesn't use these routines because it has a different
 516  * mechanism for creating devices from device tree nodes.
 517  */
 518
 519 /**
 520  * of_device_make_bus_id - Use the device node data to assign a unique name
 521  * @dev: pointer to device structure that is linked to a device tree node
 522  *
 523  * This routine will first try using either the dcr-reg or the reg property
 524  * value to derive a unique name.  As a last resort it will use the node
 525  * name followed by a unique number.
 526  */
 527 void of_device_make_bus_id(struct device *dev)
 528 {
 529         static atomic_t bus_no_reg_magic;
 530         struct device_node *node = dev->of_node;
 531         const u32 *reg;
 532         u64 addr;
 533         int magic;
 534
 535 #ifdef CONFIG_PPC_DCR
 536         /*
 537          * If it's a DCR based device, use 'd' for native DCRs
 538          * and 'D' for MMIO DCRs.
 539          */
 540         reg = of_get_property(node, "dcr-reg", NULL);
 541         if (reg) {
 542 #ifdef CONFIG_PPC_DCR_NATIVE
 543                 dev_set_name(dev, "d%x.%s", *reg, node->name);
 544 #else /* CONFIG_PPC_DCR_NATIVE */
 545                 u64 addr = of_translate_dcr_address(node, *reg, NULL);
 546                 if (addr != OF_BAD_ADDR) {
 547                         dev_set_name(dev, "D%llx.%s",
 548                                      (unsigned long long)addr, node->name);
 549                         return;
 550                 }
 551 #endif /* !CONFIG_PPC_DCR_NATIVE */
 552         }
 553 #endif /* CONFIG_PPC_DCR */
 554
 555         /*
 556          * For MMIO, get the physical address
 557          */
 558         reg = of_get_property(node, "reg", NULL);
 559         if (reg) {
 560                 addr = of_translate_address(node, reg);
 561                 if (addr != OF_BAD_ADDR) {
 562                         dev_set_name(dev, "%llx.%s",
 563                                      (unsigned long long)addr, node->name);
 564                         return;
 565                 }
 566         }
 567
 568         /*
 569          * No BusID, use the node name and add a globally incremented
 570          * counter (and pray...)
 571          */
 572         magic = atomic_add_return(1, &bus_no_reg_magic);
 573         dev_set_name(dev, "%s.%d", node->name, magic - 1);
 574 }
 575
 576 /**
 577  * of_device_alloc - Allocate and initialize an of_device
 578  * @np: device node to assign to device
 579  * @bus_id: Name to assign to the device.  May be null to use default name.
 580  * @parent: Parent device.
 581  */
 582 struct platform_device *of_device_alloc(struct device_node *np,
 583                                   const char *bus_id,
 584                                   struct device *parent)
 585 {
 586         struct platform_device *dev;
 587         int rc, i, num_reg = 0, num_irq = 0;
 588         struct resource *res, temp_res;
 589
 590         /* First count how many resources are needed */
 591         while (of_address_to_resource(np, num_reg, &temp_res) == 0)
 592                 num_reg++;
 593         while (of_irq_to_resource(np, num_irq, &temp_res) != NO_IRQ)
 594                 num_irq++;
 595
 596         /* Allocate memory for both the struct device and the resource table */
 597         dev = kzalloc(sizeof(*dev) + (sizeof(*res) * (num_reg + num_irq)),
 598                       GFP_KERNEL);
 599         if (!dev)
 600                 return NULL;
 601         res = (struct resource *) &dev[1];
 602
 603         /* Populate the resource table */
 604         if (num_irq || num_reg) {
 605                 dev->num_resources = num_reg + num_irq;
 606                 dev->resource = res;
 607                 for (i = 0; i < num_reg; i++, res++) {
 608                         rc = of_address_to_resource(np, i, res);
 609                         WARN_ON(rc);
 610                 }
 611                 for (i = 0; i < num_irq; i++, res++) {
 612                         rc = of_irq_to_resource(np, i, res);
 613                         WARN_ON(rc == NO_IRQ);
 614                 }
 615         }
 616
 617         dev->dev.of_node = of_node_get(np);
 618 #if defined(CONFIG_PPC) || defined(CONFIG_MICROBLAZE)
 619         dev->dev.dma_mask = &dev->archdata.dma_mask;
 620 #endif
 621         dev->dev.parent = parent;
 622         dev->dev.release = of_release_dev;
 623
 624         if (bus_id)
 625                 dev_set_name(&dev->dev, "%s", bus_id);
 626         else
 627                 of_device_make_bus_id(&dev->dev);
 628
 629         return dev;
 630 }
 631 EXPORT_SYMBOL(of_device_alloc);
 632
 633 /**
 634  * of_platform_device_create - Alloc, initialize and register an of_device
 635  * @np: pointer to node to create device for
 636  * @bus_id: name to assign device
 637  * @parent: Linux device model parent device.
 638  */
 639 struct platform_device *of_platform_device_create(struct device_node *np,
 640                                             const char *bus_id,
 641                                             struct device *parent)
 642 {
 643         struct platform_device *dev;
 644
 645         dev = of_device_alloc(np, bus_id, parent);
 646         if (!dev)
 647                 return NULL;
 648
 649 #if defined(CONFIG_PPC) || defined(CONFIG_MICROBLAZE)
 650         dev->archdata.dma_mask = 0xffffffffUL;
 651 #endif
 652         dev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
 653         dev->dev.bus = &platform_bus_type;
 654
 655         /* We do not fill the DMA ops for platform devices by default.
 656          * This is currently the responsibility of the platform code
 657          * to do such, possibly using a device notifier
 658          */
 659
 660         if (of_device_register(dev) != 0) {
 661                 of_device_free(dev);
 662                 return NULL;
 663         }
 664
 665         return dev;
 666 }
 667 EXPORT_SYMBOL(of_platform_device_create);
 668
 669 /**
 670  * of_platform_bus_create - Create an OF device for a bus node and all its
 671  * children. Optionally recursively instantiate matching busses.
 672  * @bus: device node of the bus to instantiate
 673  * @matches: match table, NULL to use the default, OF_NO_DEEP_PROBE to
 674  * disallow recursive creation of child busses
 675  */
 676 static int of_platform_bus_create(const struct device_node *bus,
 677                                   const struct of_device_id *matches,
 678                                   struct device *parent)
 679 {
 680         struct device_node *child;
 681         struct platform_device *dev;
 682         int rc = 0;
 683
 684         for_each_child_of_node(bus, child) {
 685                 pr_debug("   create child: %s\n", child->full_name);
 686                 dev = of_platform_device_create(child, NULL, parent);
 687                 if (dev == NULL)
 688                         rc = -ENOMEM;
 689                 else if (!of_match_node(matches, child))
 690                         continue;
 691                 if (rc == 0) {
 692                         pr_debug("   and sub busses\n");
 693                         rc = of_platform_bus_create(child, matches, &dev->dev);
 694                 }
 695                 if (rc) {
 696                         of_node_put(child);
 697                         break;
 698                 }
 699         }
 700         return rc;
 701 }
 702
 703 /**
 704  * of_platform_bus_probe - Probe the device-tree for platform busses
 705  * @root: parent of the first level to probe or NULL for the root of the tree
 706  * @matches: match table, NULL to use the default
 707  * @parent: parent to hook devices from, NULL for toplevel
 708  *
 709  * Note that children of the provided root are not instantiated as devices
 710  * unless the specified root itself matches the bus list and is not NULL.
 711  */
 712 int of_platform_bus_probe(struct device_node *root,
 713                           const struct of_device_id *matches,
 714                           struct device *parent)
 715 {
 716         struct device_node *child;
 717         struct platform_device *dev;
 718         int rc = 0;
 719
 720         if (WARN_ON(!matches || matches == OF_NO_DEEP_PROBE))
 721                 return -EINVAL;
 722         if (root == NULL)
 723                 root = of_find_node_by_path("/");
 724         else
 725                 of_node_get(root);
 726         if (root == NULL)
 727                 return -EINVAL;
 728
 729         pr_debug("of_platform_bus_probe()\n");
 730         pr_debug(" starting at: %s\n", root->full_name);
 731
 732         /* Do a self check of bus type, if there's a match, create
 733          * children
 734          */
 735         if (of_match_node(matches, root)) {
 736                 pr_debug(" root match, create all sub devices\n");
 737                 dev = of_platform_device_create(root, NULL, parent);
 738                 if (dev == NULL) {
 739                         rc = -ENOMEM;
 740                         goto bail;
 741                 }
 742                 pr_debug(" create all sub busses\n");
 743                 rc = of_platform_bus_create(root, matches, &dev->dev);
 744                 goto bail;
 745         }
 746         for_each_child_of_node(root, child) {
 747                 if (!of_match_node(matches, child))
 748                         continue;
 749
 750                 pr_debug("  match: %s\n", child->full_name);
 751                 dev = of_platform_device_create(child, NULL, parent);
 752                 if (dev == NULL)
 753                         rc = -ENOMEM;
 754                 else
 755                         rc = of_platform_bus_create(child, matches, &dev->dev);
 756                 if (rc) {
 757                         of_node_put(child);
 758                         break;
 759                 }
 760         }
 761  bail:
 762         of_node_put(root);
 763         return rc;
 764 }
 765 EXPORT_SYMBOL(of_platform_bus_probe);
 766 #endif /* !CONFIG_SPARC */