1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * platform.c - platform 'pseudo' bus for legacy devices 4 * 5 * Copyright (c) 2002-3 Patrick Mochel 6 * Copyright (c) 2002-3 Open Source Development Labs 7 * 8 * Please see Documentation/driver-api/driver-model/platform.rst for more 9 * information. 10 */ 11 12 #include <linux/string.h> 13 #include <linux/platform_device.h> 14 #include <linux/of_device.h> 15 #include <linux/of_irq.h> 16 #include <linux/module.h> 17 #include <linux/init.h> 18 #include <linux/interrupt.h> 19 #include <linux/ioport.h> 20 #include <linux/dma-mapping.h> 21 #include <linux/memblock.h> 22 #include <linux/err.h> 23 #include <linux/slab.h> 24 #include <linux/pm_runtime.h> 25 #include <linux/pm_domain.h> 26 #include <linux/idr.h> 27 #include <linux/acpi.h> 28 #include <linux/clk/clk-conf.h> 29 #include <linux/limits.h> 30 #include <linux/property.h> 31 #include <linux/kmemleak.h> 32 #include <linux/types.h> 33 #include <linux/iommu.h> 34 #include <linux/dma-map-ops.h> 35 36 #include "base.h" 37 #include "power/power.h" 38 39 /* For automatically allocated device IDs */ 40 static DEFINE_IDA(platform_devid_ida); 41 42 struct device platform_bus = { 43 .init_name = "platform", 44 }; 45 EXPORT_SYMBOL_GPL(platform_bus); 46 47 /** 48 * platform_get_resource - get a resource for a device 49 * @dev: platform device 50 * @type: resource type 51 * @num: resource index 52 * 53 * Return: a pointer to the resource or NULL on failure. 54 */ 55 struct resource *platform_get_resource(struct platform_device *dev, 56 unsigned int type, unsigned int num) 57 { 58 u32 i; 59 60 for (i = 0; i < dev->num_resources; i++) { 61 struct resource *r = &dev->resource[i]; 62 63 if (type == resource_type(r) && num-- == 0) 64 return r; 65 } 66 return NULL; 67 } 68 EXPORT_SYMBOL_GPL(platform_get_resource); 69 70 struct resource *platform_get_mem_or_io(struct platform_device *dev, 71 unsigned int num) 72 { 73 u32 i; 74 75 for (i = 0; i < dev->num_resources; i++) { 76 struct resource *r = &dev->resource[i]; 77 78 if ((resource_type(r) & (IORESOURCE_MEM | IORESOURCE_IO)) && num-- == 0) 79 return r; 80 } 81 return NULL; 82 } 83 EXPORT_SYMBOL_GPL(platform_get_mem_or_io); 84 85 #ifdef CONFIG_HAS_IOMEM 86 /** 87 * devm_platform_get_and_ioremap_resource - call devm_ioremap_resource() for a 88 * platform device and get resource 89 * 90 * @pdev: platform device to use both for memory resource lookup as well as 91 * resource management 92 * @index: resource index 93 * @res: optional output parameter to store a pointer to the obtained resource. 94 * 95 * Return: a pointer to the remapped memory or an ERR_PTR() encoded error code 96 * on failure. 97 */ 98 void __iomem * 99 devm_platform_get_and_ioremap_resource(struct platform_device *pdev, 100 unsigned int index, struct resource **res) 101 { 102 struct resource *r; 103 104 r = platform_get_resource(pdev, IORESOURCE_MEM, index); 105 if (res) 106 *res = r; 107 return devm_ioremap_resource(&pdev->dev, r); 108 } 109 EXPORT_SYMBOL_GPL(devm_platform_get_and_ioremap_resource); 110 111 /** 112 * devm_platform_ioremap_resource - call devm_ioremap_resource() for a platform 113 * device 114 * 115 * @pdev: platform device to use both for memory resource lookup as well as 116 * resource management 117 * @index: resource index 118 * 119 * Return: a pointer to the remapped memory or an ERR_PTR() encoded error code 120 * on failure. 121 */ 122 void __iomem *devm_platform_ioremap_resource(struct platform_device *pdev, 123 unsigned int index) 124 { 125 return devm_platform_get_and_ioremap_resource(pdev, index, NULL); 126 } 127 EXPORT_SYMBOL_GPL(devm_platform_ioremap_resource); 128 129 /** 130 * devm_platform_ioremap_resource_byname - call devm_ioremap_resource for 131 * a platform device, retrieve the 132 * resource by name 133 * 134 * @pdev: platform device to use both for memory resource lookup as well as 135 * resource management 136 * @name: name of the resource 137 * 138 * Return: a pointer to the remapped memory or an ERR_PTR() encoded error code 139 * on failure. 140 */ 141 void __iomem * 142 devm_platform_ioremap_resource_byname(struct platform_device *pdev, 143 const char *name) 144 { 145 struct resource *res; 146 147 res = platform_get_resource_byname(pdev, IORESOURCE_MEM, name); 148 return devm_ioremap_resource(&pdev->dev, res); 149 } 150 EXPORT_SYMBOL_GPL(devm_platform_ioremap_resource_byname); 151 #endif /* CONFIG_HAS_IOMEM */ 152 153 static const struct cpumask *get_irq_affinity(struct platform_device *dev, 154 unsigned int num) 155 { 156 const struct cpumask *mask = NULL; 157 #ifndef CONFIG_SPARC 158 struct fwnode_handle *fwnode = dev_fwnode(&dev->dev); 159 160 if (is_of_node(fwnode)) 161 mask = of_irq_get_affinity(to_of_node(fwnode), num); 162 else if (is_acpi_device_node(fwnode)) 163 mask = acpi_irq_get_affinity(ACPI_HANDLE_FWNODE(fwnode), num); 164 #endif 165 166 return mask ?: cpu_possible_mask; 167 } 168 169 /** 170 * platform_get_irq_affinity - get an optional IRQ and its affinity for a device 171 * @dev: platform device 172 * @num: interrupt number index 173 * @affinity: optional cpumask pointer to get the affinity of a per-cpu interrupt 174 * 175 * Gets an interrupt for a platform device. Device drivers should check the 176 * return value for errors so as to not pass a negative integer value to 177 * the request_irq() APIs. Optional affinity information is provided in the 178 * affinity pointer if available, and NULL otherwise. 179 * 180 * Return: non-zero interrupt number on success, negative error number on failure. 181 */ 182 int platform_get_irq_affinity(struct platform_device *dev, unsigned int num, 183 const struct cpumask **affinity) 184 { 185 int ret; 186 #ifdef CONFIG_SPARC 187 /* sparc does not have irqs represented as IORESOURCE_IRQ resources */ 188 if (!dev || num >= dev->archdata.num_irqs) 189 goto out_not_found; 190 ret = dev->archdata.irqs[num]; 191 goto out; 192 #else 193 struct fwnode_handle *fwnode = dev_fwnode(&dev->dev); 194 struct resource *r; 195 196 if (is_of_node(fwnode)) { 197 ret = of_irq_get(to_of_node(fwnode), num); 198 if (ret > 0 || ret == -EPROBE_DEFER) 199 goto out; 200 } 201 202 r = platform_get_resource(dev, IORESOURCE_IRQ, num); 203 if (is_acpi_device_node(fwnode)) { 204 if (r && r->flags & IORESOURCE_DISABLED) { 205 ret = acpi_irq_get(ACPI_HANDLE_FWNODE(fwnode), num, r); 206 if (ret) 207 goto out; 208 } 209 } 210 211 /* 212 * The resources may pass trigger flags to the irqs that need 213 * to be set up. It so happens that the trigger flags for 214 * IORESOURCE_BITS correspond 1-to-1 to the IRQF_TRIGGER* 215 * settings. 216 */ 217 if (r && r->flags & IORESOURCE_BITS) { 218 struct irq_data *irqd; 219 220 irqd = irq_get_irq_data(r->start); 221 if (!irqd) 222 goto out_not_found; 223 irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS); 224 } 225 226 if (r) { 227 ret = r->start; 228 goto out; 229 } 230 231 /* 232 * For the index 0 interrupt, allow falling back to GpioInt 233 * resources. While a device could have both Interrupt and GpioInt 234 * resources, making this fallback ambiguous, in many common cases 235 * the device will only expose one IRQ, and this fallback 236 * allows a common code path across either kind of resource. 237 */ 238 if (num == 0 && is_acpi_device_node(fwnode)) { 239 ret = acpi_dev_gpio_irq_get(to_acpi_device_node(fwnode), num); 240 /* Our callers expect -ENXIO for missing IRQs. */ 241 if (ret >= 0 || ret == -EPROBE_DEFER) 242 goto out; 243 } 244 245 #endif 246 out_not_found: 247 ret = -ENXIO; 248 out: 249 if (WARN(!ret, "0 is an invalid IRQ number\n")) 250 return -EINVAL; 251 252 if (ret > 0 && affinity) 253 *affinity = get_irq_affinity(dev, num); 254 255 return ret; 256 } 257 EXPORT_SYMBOL_GPL(platform_get_irq_affinity); 258 259 /** 260 * platform_get_irq_optional - get an optional interrupt for a device 261 * @dev: platform device 262 * @num: interrupt number index 263 * 264 * Gets an interrupt for a platform device. Device drivers should check the 265 * return value for errors so as to not pass a negative integer value to 266 * the request_irq() APIs. This is the same as platform_get_irq(), except 267 * that it does not print an error message if an interrupt can not be 268 * obtained. 269 * 270 * For example:: 271 * 272 * int irq = platform_get_irq_optional(pdev, 0); 273 * if (irq < 0) 274 * return irq; 275 * 276 * Return: non-zero interrupt number on success, negative error number on failure. 277 */ 278 int platform_get_irq_optional(struct platform_device *dev, unsigned int num) 279 { 280 return platform_get_irq_affinity(dev, num, NULL); 281 } 282 EXPORT_SYMBOL_GPL(platform_get_irq_optional); 283 284 /** 285 * platform_get_irq - get an IRQ for a device 286 * @dev: platform device 287 * @num: IRQ number index 288 * 289 * Gets an IRQ for a platform device and prints an error message if finding the 290 * IRQ fails. Device drivers should check the return value for errors so as to 291 * not pass a negative integer value to the request_irq() APIs. 292 * 293 * For example:: 294 * 295 * int irq = platform_get_irq(pdev, 0); 296 * if (irq < 0) 297 * return irq; 298 * 299 * Return: non-zero IRQ number on success, negative error number on failure. 300 */ 301 int platform_get_irq(struct platform_device *dev, unsigned int num) 302 { 303 int ret; 304 305 ret = platform_get_irq_optional(dev, num); 306 if (ret < 0) 307 return dev_err_probe(&dev->dev, ret, 308 "IRQ index %u not found\n", num); 309 310 return ret; 311 } 312 EXPORT_SYMBOL_GPL(platform_get_irq); 313 314 /** 315 * platform_irq_count - Count the number of IRQs a platform device uses 316 * @dev: platform device 317 * 318 * Return: Number of IRQs a platform device uses or EPROBE_DEFER 319 */ 320 int platform_irq_count(struct platform_device *dev) 321 { 322 int ret, nr = 0; 323 324 while ((ret = platform_get_irq_optional(dev, nr)) >= 0) 325 nr++; 326 327 if (ret == -EPROBE_DEFER) 328 return ret; 329 330 return nr; 331 } 332 EXPORT_SYMBOL_GPL(platform_irq_count); 333 334 struct irq_affinity_devres { 335 unsigned int count; 336 unsigned int irq[] __counted_by(count); 337 }; 338 339 static void platform_disable_acpi_irq(struct platform_device *pdev, int index) 340 { 341 struct resource *r; 342 343 r = platform_get_resource(pdev, IORESOURCE_IRQ, index); 344 if (r) 345 irqresource_disabled(r, 0); 346 } 347 348 static void devm_platform_get_irqs_affinity_release(struct device *dev, 349 void *res) 350 { 351 struct irq_affinity_devres *ptr = res; 352 int i; 353 354 for (i = 0; i < ptr->count; i++) { 355 irq_dispose_mapping(ptr->irq[i]); 356 357 if (is_acpi_device_node(dev_fwnode(dev))) 358 platform_disable_acpi_irq(to_platform_device(dev), i); 359 } 360 } 361 362 /** 363 * devm_platform_get_irqs_affinity - devm method to get a set of IRQs for a 364 * device using an interrupt affinity descriptor 365 * @dev: platform device pointer 366 * @affd: affinity descriptor 367 * @minvec: minimum count of interrupt vectors 368 * @maxvec: maximum count of interrupt vectors 369 * @irqs: pointer holder for IRQ numbers 370 * 371 * Gets a set of IRQs for a platform device, and updates IRQ afffinty according 372 * to the passed affinity descriptor 373 * 374 * Return: Number of vectors on success, negative error number on failure. 375 */ 376 int devm_platform_get_irqs_affinity(struct platform_device *dev, 377 struct irq_affinity *affd, 378 unsigned int minvec, 379 unsigned int maxvec, 380 int **irqs) 381 { 382 struct irq_affinity_devres *ptr; 383 struct irq_affinity_desc *desc; 384 size_t size; 385 int i, ret, nvec; 386 387 if (!affd) 388 return -EPERM; 389 390 if (maxvec < minvec) 391 return -ERANGE; 392 393 nvec = platform_irq_count(dev); 394 if (nvec < 0) 395 return nvec; 396 397 if (nvec < minvec) 398 return -ENOSPC; 399 400 nvec = irq_calc_affinity_vectors(minvec, nvec, affd); 401 if (nvec < minvec) 402 return -ENOSPC; 403 404 if (nvec > maxvec) 405 nvec = maxvec; 406 407 size = sizeof(*ptr) + sizeof(unsigned int) * nvec; 408 ptr = devres_alloc(devm_platform_get_irqs_affinity_release, size, 409 GFP_KERNEL); 410 if (!ptr) 411 return -ENOMEM; 412 413 ptr->count = nvec; 414 415 for (i = 0; i < nvec; i++) { 416 int irq = platform_get_irq(dev, i); 417 if (irq < 0) { 418 ret = irq; 419 goto err_free_devres; 420 } 421 ptr->irq[i] = irq; 422 } 423 424 desc = irq_create_affinity_masks(nvec, affd); 425 if (!desc) { 426 ret = -ENOMEM; 427 goto err_free_devres; 428 } 429 430 for (i = 0; i < nvec; i++) { 431 ret = irq_update_affinity_desc(ptr->irq[i], &desc[i]); 432 if (ret) { 433 dev_err(&dev->dev, "failed to update irq%d affinity descriptor (%d)\n", 434 ptr->irq[i], ret); 435 goto err_free_desc; 436 } 437 } 438 439 devres_add(&dev->dev, ptr); 440 441 kfree(desc); 442 443 *irqs = ptr->irq; 444 445 return nvec; 446 447 err_free_desc: 448 kfree(desc); 449 err_free_devres: 450 devres_free(ptr); 451 return ret; 452 } 453 EXPORT_SYMBOL_GPL(devm_platform_get_irqs_affinity); 454 455 /** 456 * platform_get_resource_byname - get a resource for a device by name 457 * @dev: platform device 458 * @type: resource type 459 * @name: resource name 460 */ 461 struct resource *platform_get_resource_byname(struct platform_device *dev, 462 unsigned int type, 463 const char *name) 464 { 465 u32 i; 466 467 for (i = 0; i < dev->num_resources; i++) { 468 struct resource *r = &dev->resource[i]; 469 470 if (unlikely(!r->name)) 471 continue; 472 473 if (type == resource_type(r) && !strcmp(r->name, name)) 474 return r; 475 } 476 return NULL; 477 } 478 EXPORT_SYMBOL_GPL(platform_get_resource_byname); 479 480 static int __platform_get_irq_byname(struct platform_device *dev, 481 const char *name) 482 { 483 struct resource *r; 484 int ret; 485 486 ret = fwnode_irq_get_byname(dev_fwnode(&dev->dev), name); 487 if (ret > 0 || ret == -EPROBE_DEFER) 488 return ret; 489 490 r = platform_get_resource_byname(dev, IORESOURCE_IRQ, name); 491 if (r) { 492 if (WARN(!r->start, "0 is an invalid IRQ number\n")) 493 return -EINVAL; 494 return r->start; 495 } 496 497 return -ENXIO; 498 } 499 500 /** 501 * platform_get_irq_byname - get an IRQ for a device by name 502 * @dev: platform device 503 * @name: IRQ name 504 * 505 * Get an IRQ like platform_get_irq(), but then by name rather then by index. 506 * 507 * Return: non-zero IRQ number on success, negative error number on failure. 508 */ 509 int platform_get_irq_byname(struct platform_device *dev, const char *name) 510 { 511 int ret; 512 513 ret = __platform_get_irq_byname(dev, name); 514 if (ret < 0) 515 return dev_err_probe(&dev->dev, ret, "IRQ %s not found\n", 516 name); 517 return ret; 518 } 519 EXPORT_SYMBOL_GPL(platform_get_irq_byname); 520 521 /** 522 * platform_get_irq_byname_optional - get an optional IRQ for a device by name 523 * @dev: platform device 524 * @name: IRQ name 525 * 526 * Get an optional IRQ by name like platform_get_irq_byname(). Except that it 527 * does not print an error message if an IRQ can not be obtained. 528 * 529 * Return: non-zero IRQ number on success, negative error number on failure. 530 */ 531 int platform_get_irq_byname_optional(struct platform_device *dev, 532 const char *name) 533 { 534 return __platform_get_irq_byname(dev, name); 535 } 536 EXPORT_SYMBOL_GPL(platform_get_irq_byname_optional); 537 538 /** 539 * platform_add_devices - add a numbers of platform devices 540 * @devs: array of platform devices to add 541 * @num: number of platform devices in array 542 * 543 * Return: 0 on success, negative error number on failure. 544 */ 545 int platform_add_devices(struct platform_device **devs, int num) 546 { 547 int i, ret = 0; 548 549 for (i = 0; i < num; i++) { 550 ret = platform_device_register(devs[i]); 551 if (ret) { 552 while (--i >= 0) 553 platform_device_unregister(devs[i]); 554 break; 555 } 556 } 557 558 return ret; 559 } 560 EXPORT_SYMBOL_GPL(platform_add_devices); 561 562 struct platform_object { 563 struct platform_device pdev; 564 char name[]; 565 }; 566 567 /* 568 * Set up default DMA mask for platform devices if the they weren't 569 * previously set by the architecture / DT. 570 */ 571 static void setup_pdev_dma_masks(struct platform_device *pdev) 572 { 573 pdev->dev.dma_parms = &pdev->dma_parms; 574 575 if (!pdev->dev.coherent_dma_mask) 576 pdev->dev.coherent_dma_mask = DMA_BIT_MASK(32); 577 if (!pdev->dev.dma_mask) { 578 pdev->platform_dma_mask = DMA_BIT_MASK(32); 579 pdev->dev.dma_mask = &pdev->platform_dma_mask; 580 } 581 }; 582 583 /** 584 * platform_device_put - destroy a platform device 585 * @pdev: platform device to free 586 * 587 * Free all memory associated with a platform device. This function must 588 * _only_ be externally called in error cases. All other usage is a bug. 589 */ 590 void platform_device_put(struct platform_device *pdev) 591 { 592 if (!IS_ERR_OR_NULL(pdev)) 593 put_device(&pdev->dev); 594 } 595 EXPORT_SYMBOL_GPL(platform_device_put); 596 597 static void platform_device_release(struct device *dev) 598 { 599 struct platform_object *pa = container_of(dev, struct platform_object, 600 pdev.dev); 601 602 of_node_put(pa->pdev.dev.of_node); 603 kfree(pa->pdev.dev.platform_data); 604 kfree(pa->pdev.mfd_cell); 605 kfree(pa->pdev.resource); 606 kfree(pa); 607 } 608 609 /** 610 * platform_device_alloc - create a platform device 611 * @name: base name of the device we're adding 612 * @id: instance id 613 * 614 * Create a platform device object which can have other objects attached 615 * to it, and which will have attached objects freed when it is released. 616 */ 617 struct platform_device *platform_device_alloc(const char *name, int id) 618 { 619 struct platform_object *pa; 620 621 pa = kzalloc(sizeof(*pa) + strlen(name) + 1, GFP_KERNEL); 622 if (pa) { 623 strcpy(pa->name, name); 624 pa->pdev.name = pa->name; 625 pa->pdev.id = id; 626 device_initialize(&pa->pdev.dev); 627 pa->pdev.dev.release = platform_device_release; 628 setup_pdev_dma_masks(&pa->pdev); 629 } 630 631 return pa ? &pa->pdev : NULL; 632 } 633 EXPORT_SYMBOL_GPL(platform_device_alloc); 634 635 /** 636 * platform_device_add_resources - add resources to a platform device 637 * @pdev: platform device allocated by platform_device_alloc to add resources to 638 * @res: set of resources that needs to be allocated for the device 639 * @num: number of resources 640 * 641 * Add a copy of the resources to the platform device. The memory 642 * associated with the resources will be freed when the platform device is 643 * released. 644 */ 645 int platform_device_add_resources(struct platform_device *pdev, 646 const struct resource *res, unsigned int num) 647 { 648 struct resource *r = NULL; 649 650 if (res) { 651 r = kmemdup_array(res, num, sizeof(*r), GFP_KERNEL); 652 if (!r) 653 return -ENOMEM; 654 } 655 656 kfree(pdev->resource); 657 pdev->resource = r; 658 pdev->num_resources = num; 659 return 0; 660 } 661 EXPORT_SYMBOL_GPL(platform_device_add_resources); 662 663 /** 664 * platform_device_add_data - add platform-specific data to a platform device 665 * @pdev: platform device allocated by platform_device_alloc to add resources to 666 * @data: platform specific data for this platform device 667 * @size: size of platform specific data 668 * 669 * Add a copy of platform specific data to the platform device's 670 * platform_data pointer. The memory associated with the platform data 671 * will be freed when the platform device is released. 672 */ 673 int platform_device_add_data(struct platform_device *pdev, const void *data, 674 size_t size) 675 { 676 void *d = NULL; 677 678 if (data) { 679 d = kmemdup(data, size, GFP_KERNEL); 680 if (!d) 681 return -ENOMEM; 682 } 683 684 kfree(pdev->dev.platform_data); 685 pdev->dev.platform_data = d; 686 return 0; 687 } 688 EXPORT_SYMBOL_GPL(platform_device_add_data); 689 690 /** 691 * platform_device_add - add a platform device to device hierarchy 692 * @pdev: platform device we're adding 693 * 694 * This is part 2 of platform_device_register(), though may be called 695 * separately _iff_ pdev was allocated by platform_device_alloc(). 696 */ 697 int platform_device_add(struct platform_device *pdev) 698 { 699 struct device *dev = &pdev->dev; 700 u32 i; 701 int ret; 702 703 if (!dev->parent) 704 dev->parent = &platform_bus; 705 706 dev->bus = &platform_bus_type; 707 708 switch (pdev->id) { 709 default: 710 dev_set_name(dev, "%s.%d", pdev->name, pdev->id); 711 break; 712 case PLATFORM_DEVID_NONE: 713 dev_set_name(dev, "%s", pdev->name); 714 break; 715 case PLATFORM_DEVID_AUTO: 716 /* 717 * Automatically allocated device ID. We mark it as such so 718 * that we remember it must be freed, and we append a suffix 719 * to avoid namespace collision with explicit IDs. 720 */ 721 ret = ida_alloc(&platform_devid_ida, GFP_KERNEL); 722 if (ret < 0) 723 return ret; 724 pdev->id = ret; 725 pdev->id_auto = true; 726 dev_set_name(dev, "%s.%d.auto", pdev->name, pdev->id); 727 break; 728 } 729 730 for (i = 0; i < pdev->num_resources; i++) { 731 struct resource *p, *r = &pdev->resource[i]; 732 733 if (r->name == NULL) 734 r->name = dev_name(dev); 735 736 p = r->parent; 737 if (!p) { 738 if (resource_type(r) == IORESOURCE_MEM) 739 p = &iomem_resource; 740 else if (resource_type(r) == IORESOURCE_IO) 741 p = &ioport_resource; 742 } 743 744 if (p) { 745 ret = insert_resource(p, r); 746 if (ret) { 747 dev_err(dev, "failed to claim resource %d: %pR\n", i, r); 748 goto failed; 749 } 750 } 751 } 752 753 pr_debug("Registering platform device '%s'. Parent at %s\n", dev_name(dev), 754 dev_name(dev->parent)); 755 756 ret = device_add(dev); 757 if (ret) 758 goto failed; 759 760 return 0; 761 762 failed: 763 if (pdev->id_auto) { 764 ida_free(&platform_devid_ida, pdev->id); 765 pdev->id = PLATFORM_DEVID_AUTO; 766 } 767 768 while (i--) { 769 struct resource *r = &pdev->resource[i]; 770 if (r->parent) 771 release_resource(r); 772 } 773 774 return ret; 775 } 776 EXPORT_SYMBOL_GPL(platform_device_add); 777 778 /** 779 * platform_device_del - remove a platform-level device 780 * @pdev: platform device we're removing 781 * 782 * Note that this function will also release all memory- and port-based 783 * resources owned by the device (@dev->resource). This function must 784 * _only_ be externally called in error cases. All other usage is a bug. 785 */ 786 void platform_device_del(struct platform_device *pdev) 787 { 788 u32 i; 789 790 if (!IS_ERR_OR_NULL(pdev)) { 791 device_del(&pdev->dev); 792 793 if (pdev->id_auto) { 794 ida_free(&platform_devid_ida, pdev->id); 795 pdev->id = PLATFORM_DEVID_AUTO; 796 } 797 798 for (i = 0; i < pdev->num_resources; i++) { 799 struct resource *r = &pdev->resource[i]; 800 if (r->parent) 801 release_resource(r); 802 } 803 } 804 } 805 EXPORT_SYMBOL_GPL(platform_device_del); 806 807 /** 808 * platform_device_register - add a platform-level device 809 * @pdev: platform device we're adding 810 * 811 * NOTE: _Never_ directly free @pdev after calling this function, even if it 812 * returned an error! Always use platform_device_put() to give up the 813 * reference initialised in this function instead. 814 */ 815 int platform_device_register(struct platform_device *pdev) 816 { 817 device_initialize(&pdev->dev); 818 setup_pdev_dma_masks(pdev); 819 return platform_device_add(pdev); 820 } 821 EXPORT_SYMBOL_GPL(platform_device_register); 822 823 /** 824 * platform_device_unregister - unregister a platform-level device 825 * @pdev: platform device we're unregistering 826 * 827 * Unregistration is done in 2 steps. First we release all resources 828 * and remove it from the subsystem, then we drop reference count by 829 * calling platform_device_put(). 830 */ 831 void platform_device_unregister(struct platform_device *pdev) 832 { 833 platform_device_del(pdev); 834 platform_device_put(pdev); 835 } 836 EXPORT_SYMBOL_GPL(platform_device_unregister); 837 838 /** 839 * platform_device_register_full - add a platform-level device with 840 * resources and platform-specific data 841 * 842 * @pdevinfo: data used to create device 843 * 844 * Returns &struct platform_device pointer on success, or ERR_PTR() on error. 845 */ 846 struct platform_device *platform_device_register_full(const struct platform_device_info *pdevinfo) 847 { 848 int ret; 849 struct platform_device *pdev; 850 851 if (pdevinfo->swnode && pdevinfo->properties) 852 return ERR_PTR(-EINVAL); 853 854 pdev = platform_device_alloc(pdevinfo->name, pdevinfo->id); 855 if (!pdev) 856 return ERR_PTR(-ENOMEM); 857 858 pdev->dev.parent = pdevinfo->parent; 859 pdev->dev.fwnode = pdevinfo->fwnode; 860 pdev->dev.of_node = of_node_get(to_of_node(pdev->dev.fwnode)); 861 pdev->dev.of_node_reused = pdevinfo->of_node_reused; 862 863 if (pdevinfo->dma_mask) { 864 pdev->platform_dma_mask = pdevinfo->dma_mask; 865 pdev->dev.dma_mask = &pdev->platform_dma_mask; 866 pdev->dev.coherent_dma_mask = pdevinfo->dma_mask; 867 } 868 869 ret = platform_device_add_resources(pdev, pdevinfo->res, pdevinfo->num_res); 870 if (ret) 871 goto err; 872 873 ret = platform_device_add_data(pdev, pdevinfo->data, pdevinfo->size_data); 874 if (ret) 875 goto err; 876 877 if (pdevinfo->swnode) { 878 ret = device_add_software_node(&pdev->dev, pdevinfo->swnode); 879 if (ret) 880 goto err; 881 } else if (pdevinfo->properties) { 882 ret = device_create_managed_software_node(&pdev->dev, 883 pdevinfo->properties, NULL); 884 if (ret) 885 goto err; 886 } 887 888 ret = platform_device_add(pdev); 889 if (ret) { 890 err: 891 ACPI_COMPANION_SET(&pdev->dev, NULL); 892 platform_device_put(pdev); 893 return ERR_PTR(ret); 894 } 895 896 return pdev; 897 } 898 EXPORT_SYMBOL_GPL(platform_device_register_full); 899 900 /** 901 * __platform_driver_register - register a driver for platform-level devices 902 * @drv: platform driver structure 903 * @owner: owning module/driver 904 */ 905 int __platform_driver_register(struct platform_driver *drv, struct module *owner) 906 { 907 drv->driver.owner = owner; 908 drv->driver.bus = &platform_bus_type; 909 910 return driver_register(&drv->driver); 911 } 912 EXPORT_SYMBOL_GPL(__platform_driver_register); 913 914 /** 915 * platform_driver_unregister - unregister a driver for platform-level devices 916 * @drv: platform driver structure 917 */ 918 void platform_driver_unregister(struct platform_driver *drv) 919 { 920 driver_unregister(&drv->driver); 921 } 922 EXPORT_SYMBOL_GPL(platform_driver_unregister); 923 924 static int platform_probe_fail(struct platform_device *pdev) 925 { 926 return -ENXIO; 927 } 928 929 static int is_bound_to_driver(struct device *dev, void *driver) 930 { 931 if (dev->driver == driver) 932 return 1; 933 return 0; 934 } 935 936 /** 937 * __platform_driver_probe - register driver for non-hotpluggable device 938 * @drv: platform driver structure 939 * @probe: the driver probe routine, probably from an __init section 940 * @module: module which will be the owner of the driver 941 * 942 * Use this instead of platform_driver_register() when you know the device 943 * is not hotpluggable and has already been registered, and you want to 944 * remove its run-once probe() infrastructure from memory after the driver 945 * has bound to the device. 946 * 947 * One typical use for this would be with drivers for controllers integrated 948 * into system-on-chip processors, where the controller devices have been 949 * configured as part of board setup. 950 * 951 * Note that this is incompatible with deferred probing. 952 * 953 * Returns zero if the driver registered and bound to a device, else returns 954 * a negative error code and with the driver not registered. 955 */ 956 int __init_or_module __platform_driver_probe(struct platform_driver *drv, 957 int (*probe)(struct platform_device *), 958 struct module *module) 959 { 960 int retval; 961 962 if (drv->driver.probe_type == PROBE_PREFER_ASYNCHRONOUS) { 963 pr_err("%s: drivers registered with %s can not be probed asynchronously\n", 964 drv->driver.name, __func__); 965 return -EINVAL; 966 } 967 968 /* 969 * We have to run our probes synchronously because we check if 970 * we find any devices to bind to and exit with error if there 971 * are any. 972 */ 973 drv->driver.probe_type = PROBE_FORCE_SYNCHRONOUS; 974 975 /* 976 * Prevent driver from requesting probe deferral to avoid further 977 * futile probe attempts. 978 */ 979 drv->prevent_deferred_probe = true; 980 981 /* make sure driver won't have bind/unbind attributes */ 982 drv->driver.suppress_bind_attrs = true; 983 984 /* temporary section violation during probe() */ 985 drv->probe = probe; 986 retval = __platform_driver_register(drv, module); 987 if (retval) 988 return retval; 989 990 /* Force all new probes of this driver to fail */ 991 drv->probe = platform_probe_fail; 992 993 /* Walk all platform devices and see if any actually bound to this driver. 994 * If not, return an error as the device should have done so by now. 995 */ 996 if (!bus_for_each_dev(&platform_bus_type, NULL, &drv->driver, is_bound_to_driver)) { 997 retval = -ENODEV; 998 platform_driver_unregister(drv); 999 } 1000 1001 return retval; 1002 } 1003 EXPORT_SYMBOL_GPL(__platform_driver_probe); 1004 1005 /** 1006 * __platform_create_bundle - register driver and create corresponding device 1007 * @driver: platform driver structure 1008 * @probe: the driver probe routine, probably from an __init section 1009 * @res: set of resources that needs to be allocated for the device 1010 * @n_res: number of resources 1011 * @data: platform specific data for this platform device 1012 * @size: size of platform specific data 1013 * @module: module which will be the owner of the driver 1014 * 1015 * Use this in legacy-style modules that probe hardware directly and 1016 * register a single platform device and corresponding platform driver. 1017 * 1018 * Returns &struct platform_device pointer on success, or ERR_PTR() on error. 1019 */ 1020 struct platform_device * __init_or_module 1021 __platform_create_bundle(struct platform_driver *driver, 1022 int (*probe)(struct platform_device *), 1023 struct resource *res, unsigned int n_res, 1024 const void *data, size_t size, struct module *module) 1025 { 1026 struct platform_device *pdev; 1027 int error; 1028 1029 pdev = platform_device_alloc(driver->driver.name, PLATFORM_DEVID_NONE); 1030 if (!pdev) { 1031 error = -ENOMEM; 1032 goto err_out; 1033 } 1034 1035 error = platform_device_add_resources(pdev, res, n_res); 1036 if (error) 1037 goto err_pdev_put; 1038 1039 error = platform_device_add_data(pdev, data, size); 1040 if (error) 1041 goto err_pdev_put; 1042 1043 error = platform_device_add(pdev); 1044 if (error) 1045 goto err_pdev_put; 1046 1047 error = __platform_driver_probe(driver, probe, module); 1048 if (error) 1049 goto err_pdev_del; 1050 1051 return pdev; 1052 1053 err_pdev_del: 1054 platform_device_del(pdev); 1055 err_pdev_put: 1056 platform_device_put(pdev); 1057 err_out: 1058 return ERR_PTR(error); 1059 } 1060 EXPORT_SYMBOL_GPL(__platform_create_bundle); 1061 1062 /** 1063 * __platform_register_drivers - register an array of platform drivers 1064 * @drivers: an array of drivers to register 1065 * @count: the number of drivers to register 1066 * @owner: module owning the drivers 1067 * 1068 * Registers platform drivers specified by an array. On failure to register a 1069 * driver, all previously registered drivers will be unregistered. Callers of 1070 * this API should use platform_unregister_drivers() to unregister drivers in 1071 * the reverse order. 1072 * 1073 * Returns: 0 on success or a negative error code on failure. 1074 */ 1075 int __platform_register_drivers(struct platform_driver * const *drivers, 1076 unsigned int count, struct module *owner) 1077 { 1078 unsigned int i; 1079 int err; 1080 1081 for (i = 0; i < count; i++) { 1082 pr_debug("registering platform driver %ps\n", drivers[i]); 1083 1084 err = __platform_driver_register(drivers[i], owner); 1085 if (err < 0) { 1086 pr_err("failed to register platform driver %ps: %d\n", 1087 drivers[i], err); 1088 goto error; 1089 } 1090 } 1091 1092 return 0; 1093 1094 error: 1095 while (i--) { 1096 pr_debug("unregistering platform driver %ps\n", drivers[i]); 1097 platform_driver_unregister(drivers[i]); 1098 } 1099 1100 return err; 1101 } 1102 EXPORT_SYMBOL_GPL(__platform_register_drivers); 1103 1104 /** 1105 * platform_unregister_drivers - unregister an array of platform drivers 1106 * @drivers: an array of drivers to unregister 1107 * @count: the number of drivers to unregister 1108 * 1109 * Unregisters platform drivers specified by an array. This is typically used 1110 * to complement an earlier call to platform_register_drivers(). Drivers are 1111 * unregistered in the reverse order in which they were registered. 1112 */ 1113 void platform_unregister_drivers(struct platform_driver * const *drivers, 1114 unsigned int count) 1115 { 1116 while (count--) { 1117 pr_debug("unregistering platform driver %ps\n", drivers[count]); 1118 platform_driver_unregister(drivers[count]); 1119 } 1120 } 1121 EXPORT_SYMBOL_GPL(platform_unregister_drivers); 1122 1123 static const struct platform_device_id * 1124 platform_match_id(const struct platform_device_id *id, struct platform_device *pdev) 1125 { 1126 while (id->name[0]) { 1127 if (strcmp(pdev->name, id->name) == 0) { 1128 pdev->id_entry = id; 1129 return id; 1130 } 1131 id++; 1132 } 1133 return NULL; 1134 } 1135 1136 #ifdef CONFIG_PM_SLEEP 1137 1138 static int platform_legacy_suspend(struct device *dev, pm_message_t mesg) 1139 { 1140 struct platform_driver *pdrv = to_platform_driver(dev->driver); 1141 struct platform_device *pdev = to_platform_device(dev); 1142 int ret = 0; 1143 1144 if (dev->driver && pdrv->suspend) 1145 ret = pdrv->suspend(pdev, mesg); 1146 1147 return ret; 1148 } 1149 1150 static int platform_legacy_resume(struct device *dev) 1151 { 1152 struct platform_driver *pdrv = to_platform_driver(dev->driver); 1153 struct platform_device *pdev = to_platform_device(dev); 1154 int ret = 0; 1155 1156 if (dev->driver && pdrv->resume) 1157 ret = pdrv->resume(pdev); 1158 1159 return ret; 1160 } 1161 1162 #endif /* CONFIG_PM_SLEEP */ 1163 1164 #ifdef CONFIG_SUSPEND 1165 1166 int platform_pm_suspend(struct device *dev) 1167 { 1168 const struct device_driver *drv = dev->driver; 1169 int ret = 0; 1170 1171 if (!drv) 1172 return 0; 1173 1174 if (drv->pm) { 1175 if (drv->pm->suspend) 1176 ret = drv->pm->suspend(dev); 1177 } else { 1178 ret = platform_legacy_suspend(dev, PMSG_SUSPEND); 1179 } 1180 1181 return ret; 1182 } 1183 1184 int platform_pm_resume(struct device *dev) 1185 { 1186 const struct device_driver *drv = dev->driver; 1187 int ret = 0; 1188 1189 if (!drv) 1190 return 0; 1191 1192 if (drv->pm) { 1193 if (drv->pm->resume) 1194 ret = drv->pm->resume(dev); 1195 } else { 1196 ret = platform_legacy_resume(dev); 1197 } 1198 1199 return ret; 1200 } 1201 1202 #endif /* CONFIG_SUSPEND */ 1203 1204 #ifdef CONFIG_HIBERNATE_CALLBACKS 1205 1206 int platform_pm_freeze(struct device *dev) 1207 { 1208 const struct device_driver *drv = dev->driver; 1209 int ret = 0; 1210 1211 if (!drv) 1212 return 0; 1213 1214 if (drv->pm) { 1215 if (drv->pm->freeze) 1216 ret = drv->pm->freeze(dev); 1217 } else { 1218 ret = platform_legacy_suspend(dev, PMSG_FREEZE); 1219 } 1220 1221 return ret; 1222 } 1223 1224 int platform_pm_thaw(struct device *dev) 1225 { 1226 const struct device_driver *drv = dev->driver; 1227 int ret = 0; 1228 1229 if (!drv) 1230 return 0; 1231 1232 if (drv->pm) { 1233 if (drv->pm->thaw) 1234 ret = drv->pm->thaw(dev); 1235 } else { 1236 ret = platform_legacy_resume(dev); 1237 } 1238 1239 return ret; 1240 } 1241 1242 int platform_pm_poweroff(struct device *dev) 1243 { 1244 const struct device_driver *drv = dev->driver; 1245 int ret = 0; 1246 1247 if (!drv) 1248 return 0; 1249 1250 if (drv->pm) { 1251 if (drv->pm->poweroff) 1252 ret = drv->pm->poweroff(dev); 1253 } else { 1254 ret = platform_legacy_suspend(dev, PMSG_HIBERNATE); 1255 } 1256 1257 return ret; 1258 } 1259 1260 int platform_pm_restore(struct device *dev) 1261 { 1262 const struct device_driver *drv = dev->driver; 1263 int ret = 0; 1264 1265 if (!drv) 1266 return 0; 1267 1268 if (drv->pm) { 1269 if (drv->pm->restore) 1270 ret = drv->pm->restore(dev); 1271 } else { 1272 ret = platform_legacy_resume(dev); 1273 } 1274 1275 return ret; 1276 } 1277 1278 #endif /* CONFIG_HIBERNATE_CALLBACKS */ 1279 1280 /* modalias support enables more hands-off userspace setup: 1281 * (a) environment variable lets new-style hotplug events work once system is 1282 * fully running: "modprobe $MODALIAS" 1283 * (b) sysfs attribute lets new-style coldplug recover from hotplug events 1284 * mishandled before system is fully running: "modprobe $(cat modalias)" 1285 */ 1286 static ssize_t modalias_show(struct device *dev, 1287 struct device_attribute *attr, char *buf) 1288 { 1289 struct platform_device *pdev = to_platform_device(dev); 1290 int len; 1291 1292 len = of_device_modalias(dev, buf, PAGE_SIZE); 1293 if (len != -ENODEV) 1294 return len; 1295 1296 len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1); 1297 if (len != -ENODEV) 1298 return len; 1299 1300 return sysfs_emit(buf, "platform:%s\n", pdev->name); 1301 } 1302 static DEVICE_ATTR_RO(modalias); 1303 1304 static ssize_t numa_node_show(struct device *dev, 1305 struct device_attribute *attr, char *buf) 1306 { 1307 return sysfs_emit(buf, "%d\n", dev_to_node(dev)); 1308 } 1309 static DEVICE_ATTR_RO(numa_node); 1310 1311 static struct attribute *platform_dev_attrs[] = { 1312 &dev_attr_modalias.attr, 1313 &dev_attr_numa_node.attr, 1314 NULL, 1315 }; 1316 1317 static umode_t platform_dev_attrs_visible(struct kobject *kobj, 1318 struct attribute *a, int n) 1319 { 1320 struct device *dev = container_of(kobj, typeof(*dev), kobj); 1321 1322 if (a == &dev_attr_numa_node.attr && dev_to_node(dev) == NUMA_NO_NODE) 1323 return 0; 1324 1325 return a->mode; 1326 } 1327 1328 static const struct attribute_group platform_dev_group = { 1329 .attrs = platform_dev_attrs, 1330 .is_visible = platform_dev_attrs_visible, 1331 }; 1332 __ATTRIBUTE_GROUPS(platform_dev); 1333 1334 /** 1335 * platform_match - bind platform device to platform driver. 1336 * @dev: device. 1337 * @drv: driver. 1338 * 1339 * Platform device IDs are assumed to be encoded like this: 1340 * "<name><instance>", where <name> is a short description of the type of 1341 * device, like "pci" or "floppy", and <instance> is the enumerated 1342 * instance of the device, like '0' or '42'. Driver IDs are simply 1343 * "<name>". So, extract the <name> from the platform_device structure, 1344 * and compare it against the name of the driver. Return whether they match 1345 * or not. 1346 */ 1347 static int platform_match(struct device *dev, const struct device_driver *drv) 1348 { 1349 struct platform_device *pdev = to_platform_device(dev); 1350 struct platform_driver *pdrv = to_platform_driver(drv); 1351 int ret; 1352 1353 /* When driver_override is set, only bind to the matching driver */ 1354 ret = device_match_driver_override(dev, drv); 1355 if (ret >= 0) 1356 return ret; 1357 1358 /* Attempt an OF style match first */ 1359 if (of_driver_match_device(dev, drv)) 1360 return 1; 1361 1362 /* Then try ACPI style match */ 1363 if (acpi_driver_match_device(dev, drv)) 1364 return 1; 1365 1366 /* Then try to match against the id table */ 1367 if (pdrv->id_table) 1368 return platform_match_id(pdrv->id_table, pdev) != NULL; 1369 1370 /* fall-back to driver name match */ 1371 return (strcmp(pdev->name, drv->name) == 0); 1372 } 1373 1374 static int platform_uevent(const struct device *dev, struct kobj_uevent_env *env) 1375 { 1376 const struct platform_device *pdev = to_platform_device(dev); 1377 int rc; 1378 1379 /* Some devices have extra OF data and an OF-style MODALIAS */ 1380 rc = of_device_uevent_modalias(dev, env); 1381 if (rc != -ENODEV) 1382 return rc; 1383 1384 rc = acpi_device_uevent_modalias(dev, env); 1385 if (rc != -ENODEV) 1386 return rc; 1387 1388 add_uevent_var(env, "MODALIAS=%s%s", PLATFORM_MODULE_PREFIX, pdev->name); 1389 return 0; 1390 } 1391 1392 static int platform_probe(struct device *_dev) 1393 { 1394 struct platform_driver *drv = to_platform_driver(_dev->driver); 1395 struct platform_device *dev = to_platform_device(_dev); 1396 int ret; 1397 1398 /* 1399 * A driver registered using platform_driver_probe() cannot be bound 1400 * again later because the probe function usually lives in __init code 1401 * and so is gone. For these drivers .probe is set to 1402 * platform_probe_fail in __platform_driver_probe(). Don't even prepare 1403 * clocks and PM domains for these to match the traditional behaviour. 1404 */ 1405 if (unlikely(drv->probe == platform_probe_fail)) 1406 return -ENXIO; 1407 1408 ret = of_clk_set_defaults(_dev->of_node, false); 1409 if (ret < 0) 1410 return ret; 1411 1412 ret = dev_pm_domain_attach(_dev, PD_FLAG_ATTACH_POWER_ON | 1413 PD_FLAG_DETACH_POWER_OFF); 1414 if (ret) 1415 goto out; 1416 1417 if (drv->probe) 1418 ret = drv->probe(dev); 1419 1420 out: 1421 if (drv->prevent_deferred_probe && ret == -EPROBE_DEFER) { 1422 dev_warn(_dev, "probe deferral not supported\n"); 1423 ret = -ENXIO; 1424 } 1425 1426 return ret; 1427 } 1428 1429 static void platform_remove(struct device *_dev) 1430 { 1431 struct platform_driver *drv = to_platform_driver(_dev->driver); 1432 struct platform_device *dev = to_platform_device(_dev); 1433 1434 if (drv->remove) 1435 drv->remove(dev); 1436 } 1437 1438 static void platform_shutdown(struct device *_dev) 1439 { 1440 struct platform_device *dev = to_platform_device(_dev); 1441 struct platform_driver *drv; 1442 1443 if (!_dev->driver) 1444 return; 1445 1446 drv = to_platform_driver(_dev->driver); 1447 if (drv->shutdown) 1448 drv->shutdown(dev); 1449 } 1450 1451 static int platform_dma_configure(struct device *dev) 1452 { 1453 struct device_driver *drv = READ_ONCE(dev->driver); 1454 struct fwnode_handle *fwnode = dev_fwnode(dev); 1455 enum dev_dma_attr attr; 1456 int ret = 0; 1457 1458 if (is_of_node(fwnode)) { 1459 ret = of_dma_configure(dev, to_of_node(fwnode), true); 1460 } else if (is_acpi_device_node(fwnode)) { 1461 attr = acpi_get_dma_attr(to_acpi_device_node(fwnode)); 1462 ret = acpi_dma_configure(dev, attr); 1463 } 1464 /* @dev->driver may not be valid when we're called from the IOMMU layer */ 1465 if (ret || !drv || to_platform_driver(drv)->driver_managed_dma) 1466 return ret; 1467 1468 ret = iommu_device_use_default_domain(dev); 1469 if (ret) 1470 arch_teardown_dma_ops(dev); 1471 1472 return ret; 1473 } 1474 1475 static void platform_dma_cleanup(struct device *dev) 1476 { 1477 struct platform_driver *drv = to_platform_driver(dev->driver); 1478 1479 if (!drv->driver_managed_dma) 1480 iommu_device_unuse_default_domain(dev); 1481 } 1482 1483 static const struct dev_pm_ops platform_dev_pm_ops = { 1484 SET_RUNTIME_PM_OPS(pm_generic_runtime_suspend, pm_generic_runtime_resume, NULL) 1485 USE_PLATFORM_PM_SLEEP_OPS 1486 }; 1487 1488 const struct bus_type platform_bus_type = { 1489 .name = "platform", 1490 .dev_groups = platform_dev_groups, 1491 .driver_override = true, 1492 .match = platform_match, 1493 .uevent = platform_uevent, 1494 .probe = platform_probe, 1495 .remove = platform_remove, 1496 .shutdown = platform_shutdown, 1497 .dma_configure = platform_dma_configure, 1498 .dma_cleanup = platform_dma_cleanup, 1499 .pm = &platform_dev_pm_ops, 1500 }; 1501 EXPORT_SYMBOL_GPL(platform_bus_type); 1502 1503 static inline int __platform_match(struct device *dev, const void *drv) 1504 { 1505 return platform_match(dev, (struct device_driver *)drv); 1506 } 1507 1508 /** 1509 * platform_find_device_by_driver - Find a platform device with a given 1510 * driver. 1511 * @start: The device to start the search from. 1512 * @drv: The device driver to look for. 1513 */ 1514 struct device *platform_find_device_by_driver(struct device *start, 1515 const struct device_driver *drv) 1516 { 1517 return bus_find_device(&platform_bus_type, start, drv, 1518 __platform_match); 1519 } 1520 EXPORT_SYMBOL_GPL(platform_find_device_by_driver); 1521 1522 void __weak __init early_platform_cleanup(void) { } 1523 1524 int __init platform_bus_init(void) 1525 { 1526 int error; 1527 1528 early_platform_cleanup(); 1529 1530 error = device_register(&platform_bus); 1531 if (error) { 1532 put_device(&platform_bus); 1533 return error; 1534 } 1535 error = bus_register(&platform_bus_type); 1536 if (error) 1537 device_unregister(&platform_bus); 1538 1539 return error; 1540 } 1541