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 34 #include "base.h" 35 #include "power/power.h" 36 37 /* For automatically allocated device IDs */ 38 static DEFINE_IDA(platform_devid_ida); 39 40 struct device platform_bus = { 41 .init_name = "platform", 42 }; 43 EXPORT_SYMBOL_GPL(platform_bus); 44 45 /** 46 * platform_get_resource - get a resource for a device 47 * @dev: platform device 48 * @type: resource type 49 * @num: resource index 50 * 51 * Return: a pointer to the resource or NULL on failure. 52 */ 53 struct resource *platform_get_resource(struct platform_device *dev, 54 unsigned int type, unsigned int num) 55 { 56 u32 i; 57 58 for (i = 0; i < dev->num_resources; i++) { 59 struct resource *r = &dev->resource[i]; 60 61 if (type == resource_type(r) && num-- == 0) 62 return r; 63 } 64 return NULL; 65 } 66 EXPORT_SYMBOL_GPL(platform_get_resource); 67 68 struct resource *platform_get_mem_or_io(struct platform_device *dev, 69 unsigned int num) 70 { 71 u32 i; 72 73 for (i = 0; i < dev->num_resources; i++) { 74 struct resource *r = &dev->resource[i]; 75 76 if ((resource_type(r) & (IORESOURCE_MEM|IORESOURCE_IO)) && num-- == 0) 77 return r; 78 } 79 return NULL; 80 } 81 EXPORT_SYMBOL_GPL(platform_get_mem_or_io); 82 83 #ifdef CONFIG_HAS_IOMEM 84 /** 85 * devm_platform_get_and_ioremap_resource - call devm_ioremap_resource() for a 86 * platform device and get resource 87 * 88 * @pdev: platform device to use both for memory resource lookup as well as 89 * resource management 90 * @index: resource index 91 * @res: optional output parameter to store a pointer to the obtained resource. 92 * 93 * Return: a pointer to the remapped memory or an ERR_PTR() encoded error code 94 * on failure. 95 */ 96 void __iomem * 97 devm_platform_get_and_ioremap_resource(struct platform_device *pdev, 98 unsigned int index, struct resource **res) 99 { 100 struct resource *r; 101 102 r = platform_get_resource(pdev, IORESOURCE_MEM, index); 103 if (res) 104 *res = r; 105 return devm_ioremap_resource(&pdev->dev, r); 106 } 107 EXPORT_SYMBOL_GPL(devm_platform_get_and_ioremap_resource); 108 109 /** 110 * devm_platform_ioremap_resource - call devm_ioremap_resource() for a platform 111 * device 112 * 113 * @pdev: platform device to use both for memory resource lookup as well as 114 * resource management 115 * @index: resource index 116 * 117 * Return: a pointer to the remapped memory or an ERR_PTR() encoded error code 118 * on failure. 119 */ 120 void __iomem *devm_platform_ioremap_resource(struct platform_device *pdev, 121 unsigned int index) 122 { 123 return devm_platform_get_and_ioremap_resource(pdev, index, NULL); 124 } 125 EXPORT_SYMBOL_GPL(devm_platform_ioremap_resource); 126 127 /** 128 * devm_platform_ioremap_resource_wc - write-combined variant of 129 * devm_platform_ioremap_resource() 130 * 131 * @pdev: platform device to use both for memory resource lookup as well as 132 * resource management 133 * @index: resource index 134 * 135 * Return: a pointer to the remapped memory or an ERR_PTR() encoded error code 136 * on failure. 137 */ 138 void __iomem *devm_platform_ioremap_resource_wc(struct platform_device *pdev, 139 unsigned int index) 140 { 141 struct resource *res; 142 143 res = platform_get_resource(pdev, IORESOURCE_MEM, index); 144 return devm_ioremap_resource_wc(&pdev->dev, res); 145 } 146 147 /** 148 * devm_platform_ioremap_resource_byname - call devm_ioremap_resource for 149 * a platform device, retrieve the 150 * resource by name 151 * 152 * @pdev: platform device to use both for memory resource lookup as well as 153 * resource management 154 * @name: name of the resource 155 * 156 * Return: a pointer to the remapped memory or an ERR_PTR() encoded error code 157 * on failure. 158 */ 159 void __iomem * 160 devm_platform_ioremap_resource_byname(struct platform_device *pdev, 161 const char *name) 162 { 163 struct resource *res; 164 165 res = platform_get_resource_byname(pdev, IORESOURCE_MEM, name); 166 return devm_ioremap_resource(&pdev->dev, res); 167 } 168 EXPORT_SYMBOL_GPL(devm_platform_ioremap_resource_byname); 169 #endif /* CONFIG_HAS_IOMEM */ 170 171 /** 172 * platform_get_irq_optional - get an optional IRQ for a device 173 * @dev: platform device 174 * @num: IRQ number index 175 * 176 * Gets an IRQ for a platform device. Device drivers should check the return 177 * value for errors so as to not pass a negative integer value to the 178 * request_irq() APIs. This is the same as platform_get_irq(), except that it 179 * does not print an error message if an IRQ can not be obtained. 180 * 181 * For example:: 182 * 183 * int irq = platform_get_irq_optional(pdev, 0); 184 * if (irq < 0) 185 * return irq; 186 * 187 * Return: non-zero IRQ number on success, negative error number on failure. 188 */ 189 int platform_get_irq_optional(struct platform_device *dev, unsigned int num) 190 { 191 int ret; 192 #ifdef CONFIG_SPARC 193 /* sparc does not have irqs represented as IORESOURCE_IRQ resources */ 194 if (!dev || num >= dev->archdata.num_irqs) 195 return -ENXIO; 196 ret = dev->archdata.irqs[num]; 197 goto out; 198 #else 199 struct resource *r; 200 201 if (IS_ENABLED(CONFIG_OF_IRQ) && dev->dev.of_node) { 202 ret = of_irq_get(dev->dev.of_node, num); 203 if (ret > 0 || ret == -EPROBE_DEFER) 204 goto out; 205 } 206 207 r = platform_get_resource(dev, IORESOURCE_IRQ, num); 208 if (has_acpi_companion(&dev->dev)) { 209 if (r && r->flags & IORESOURCE_DISABLED) { 210 ret = acpi_irq_get(ACPI_HANDLE(&dev->dev), num, r); 211 if (ret) 212 goto out; 213 } 214 } 215 216 /* 217 * The resources may pass trigger flags to the irqs that need 218 * to be set up. It so happens that the trigger flags for 219 * IORESOURCE_BITS correspond 1-to-1 to the IRQF_TRIGGER* 220 * settings. 221 */ 222 if (r && r->flags & IORESOURCE_BITS) { 223 struct irq_data *irqd; 224 225 irqd = irq_get_irq_data(r->start); 226 if (!irqd) { 227 ret = -ENXIO; 228 goto out; 229 } 230 irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS); 231 } 232 233 if (r) { 234 ret = r->start; 235 goto out; 236 } 237 238 /* 239 * For the index 0 interrupt, allow falling back to GpioInt 240 * resources. While a device could have both Interrupt and GpioInt 241 * resources, making this fallback ambiguous, in many common cases 242 * the device will only expose one IRQ, and this fallback 243 * allows a common code path across either kind of resource. 244 */ 245 if (num == 0 && has_acpi_companion(&dev->dev)) { 246 ret = acpi_dev_gpio_irq_get(ACPI_COMPANION(&dev->dev), num); 247 /* Our callers expect -ENXIO for missing IRQs. */ 248 if (ret >= 0 || ret == -EPROBE_DEFER) 249 goto out; 250 } 251 252 ret = -ENXIO; 253 #endif 254 out: 255 WARN(ret == 0, "0 is an invalid IRQ number\n"); 256 return ret; 257 } 258 EXPORT_SYMBOL_GPL(platform_get_irq_optional); 259 260 /** 261 * platform_get_irq - get an IRQ for a device 262 * @dev: platform device 263 * @num: IRQ number index 264 * 265 * Gets an IRQ for a platform device and prints an error message if finding the 266 * IRQ fails. Device drivers should check the return value for errors so as to 267 * not pass a negative integer value to the request_irq() APIs. 268 * 269 * For example:: 270 * 271 * int irq = platform_get_irq(pdev, 0); 272 * if (irq < 0) 273 * return irq; 274 * 275 * Return: non-zero IRQ number on success, negative error number on failure. 276 */ 277 int platform_get_irq(struct platform_device *dev, unsigned int num) 278 { 279 int ret; 280 281 ret = platform_get_irq_optional(dev, num); 282 if (ret < 0 && ret != -EPROBE_DEFER) 283 dev_err(&dev->dev, "IRQ index %u not found\n", num); 284 285 return ret; 286 } 287 EXPORT_SYMBOL_GPL(platform_get_irq); 288 289 /** 290 * platform_irq_count - Count the number of IRQs a platform device uses 291 * @dev: platform device 292 * 293 * Return: Number of IRQs a platform device uses or EPROBE_DEFER 294 */ 295 int platform_irq_count(struct platform_device *dev) 296 { 297 int ret, nr = 0; 298 299 while ((ret = platform_get_irq_optional(dev, nr)) >= 0) 300 nr++; 301 302 if (ret == -EPROBE_DEFER) 303 return ret; 304 305 return nr; 306 } 307 EXPORT_SYMBOL_GPL(platform_irq_count); 308 309 struct irq_affinity_devres { 310 unsigned int count; 311 unsigned int irq[]; 312 }; 313 314 static void platform_disable_acpi_irq(struct platform_device *pdev, int index) 315 { 316 struct resource *r; 317 318 r = platform_get_resource(pdev, IORESOURCE_IRQ, index); 319 if (r) 320 irqresource_disabled(r, 0); 321 } 322 323 static void devm_platform_get_irqs_affinity_release(struct device *dev, 324 void *res) 325 { 326 struct irq_affinity_devres *ptr = res; 327 int i; 328 329 for (i = 0; i < ptr->count; i++) { 330 irq_dispose_mapping(ptr->irq[i]); 331 332 if (has_acpi_companion(dev)) 333 platform_disable_acpi_irq(to_platform_device(dev), i); 334 } 335 } 336 337 /** 338 * devm_platform_get_irqs_affinity - devm method to get a set of IRQs for a 339 * device using an interrupt affinity descriptor 340 * @dev: platform device pointer 341 * @affd: affinity descriptor 342 * @minvec: minimum count of interrupt vectors 343 * @maxvec: maximum count of interrupt vectors 344 * @irqs: pointer holder for IRQ numbers 345 * 346 * Gets a set of IRQs for a platform device, and updates IRQ afffinty according 347 * to the passed affinity descriptor 348 * 349 * Return: Number of vectors on success, negative error number on failure. 350 */ 351 int devm_platform_get_irqs_affinity(struct platform_device *dev, 352 struct irq_affinity *affd, 353 unsigned int minvec, 354 unsigned int maxvec, 355 int **irqs) 356 { 357 struct irq_affinity_devres *ptr; 358 struct irq_affinity_desc *desc; 359 size_t size; 360 int i, ret, nvec; 361 362 if (!affd) 363 return -EPERM; 364 365 if (maxvec < minvec) 366 return -ERANGE; 367 368 nvec = platform_irq_count(dev); 369 if (nvec < 0) 370 return nvec; 371 372 if (nvec < minvec) 373 return -ENOSPC; 374 375 nvec = irq_calc_affinity_vectors(minvec, nvec, affd); 376 if (nvec < minvec) 377 return -ENOSPC; 378 379 if (nvec > maxvec) 380 nvec = maxvec; 381 382 size = sizeof(*ptr) + sizeof(unsigned int) * nvec; 383 ptr = devres_alloc(devm_platform_get_irqs_affinity_release, size, 384 GFP_KERNEL); 385 if (!ptr) 386 return -ENOMEM; 387 388 ptr->count = nvec; 389 390 for (i = 0; i < nvec; i++) { 391 int irq = platform_get_irq(dev, i); 392 if (irq < 0) { 393 ret = irq; 394 goto err_free_devres; 395 } 396 ptr->irq[i] = irq; 397 } 398 399 desc = irq_create_affinity_masks(nvec, affd); 400 if (!desc) { 401 ret = -ENOMEM; 402 goto err_free_devres; 403 } 404 405 for (i = 0; i < nvec; i++) { 406 ret = irq_update_affinity_desc(ptr->irq[i], &desc[i]); 407 if (ret) { 408 dev_err(&dev->dev, "failed to update irq%d affinity descriptor (%d)\n", 409 ptr->irq[i], ret); 410 goto err_free_desc; 411 } 412 } 413 414 devres_add(&dev->dev, ptr); 415 416 kfree(desc); 417 418 *irqs = ptr->irq; 419 420 return nvec; 421 422 err_free_desc: 423 kfree(desc); 424 err_free_devres: 425 devres_free(ptr); 426 return ret; 427 } 428 EXPORT_SYMBOL_GPL(devm_platform_get_irqs_affinity); 429 430 /** 431 * platform_get_resource_byname - get a resource for a device by name 432 * @dev: platform device 433 * @type: resource type 434 * @name: resource name 435 */ 436 struct resource *platform_get_resource_byname(struct platform_device *dev, 437 unsigned int type, 438 const char *name) 439 { 440 u32 i; 441 442 for (i = 0; i < dev->num_resources; i++) { 443 struct resource *r = &dev->resource[i]; 444 445 if (unlikely(!r->name)) 446 continue; 447 448 if (type == resource_type(r) && !strcmp(r->name, name)) 449 return r; 450 } 451 return NULL; 452 } 453 EXPORT_SYMBOL_GPL(platform_get_resource_byname); 454 455 static int __platform_get_irq_byname(struct platform_device *dev, 456 const char *name) 457 { 458 struct resource *r; 459 int ret; 460 461 if (IS_ENABLED(CONFIG_OF_IRQ) && dev->dev.of_node) { 462 ret = of_irq_get_byname(dev->dev.of_node, name); 463 if (ret > 0 || ret == -EPROBE_DEFER) 464 return ret; 465 } 466 467 r = platform_get_resource_byname(dev, IORESOURCE_IRQ, name); 468 if (r) { 469 WARN(r->start == 0, "0 is an invalid IRQ number\n"); 470 return r->start; 471 } 472 473 return -ENXIO; 474 } 475 476 /** 477 * platform_get_irq_byname - get an IRQ for a device by name 478 * @dev: platform device 479 * @name: IRQ name 480 * 481 * Get an IRQ like platform_get_irq(), but then by name rather then by index. 482 * 483 * Return: non-zero IRQ number on success, negative error number on failure. 484 */ 485 int platform_get_irq_byname(struct platform_device *dev, const char *name) 486 { 487 int ret; 488 489 ret = __platform_get_irq_byname(dev, name); 490 if (ret < 0 && ret != -EPROBE_DEFER) 491 dev_err(&dev->dev, "IRQ %s not found\n", name); 492 493 return ret; 494 } 495 EXPORT_SYMBOL_GPL(platform_get_irq_byname); 496 497 /** 498 * platform_get_irq_byname_optional - get an optional IRQ for a device by name 499 * @dev: platform device 500 * @name: IRQ name 501 * 502 * Get an optional IRQ by name like platform_get_irq_byname(). Except that it 503 * does not print an error message if an IRQ can not be obtained. 504 * 505 * Return: non-zero IRQ number on success, negative error number on failure. 506 */ 507 int platform_get_irq_byname_optional(struct platform_device *dev, 508 const char *name) 509 { 510 return __platform_get_irq_byname(dev, name); 511 } 512 EXPORT_SYMBOL_GPL(platform_get_irq_byname_optional); 513 514 /** 515 * platform_add_devices - add a numbers of platform devices 516 * @devs: array of platform devices to add 517 * @num: number of platform devices in array 518 */ 519 int platform_add_devices(struct platform_device **devs, int num) 520 { 521 int i, ret = 0; 522 523 for (i = 0; i < num; i++) { 524 ret = platform_device_register(devs[i]); 525 if (ret) { 526 while (--i >= 0) 527 platform_device_unregister(devs[i]); 528 break; 529 } 530 } 531 532 return ret; 533 } 534 EXPORT_SYMBOL_GPL(platform_add_devices); 535 536 struct platform_object { 537 struct platform_device pdev; 538 char name[]; 539 }; 540 541 /* 542 * Set up default DMA mask for platform devices if the they weren't 543 * previously set by the architecture / DT. 544 */ 545 static void setup_pdev_dma_masks(struct platform_device *pdev) 546 { 547 pdev->dev.dma_parms = &pdev->dma_parms; 548 549 if (!pdev->dev.coherent_dma_mask) 550 pdev->dev.coherent_dma_mask = DMA_BIT_MASK(32); 551 if (!pdev->dev.dma_mask) { 552 pdev->platform_dma_mask = DMA_BIT_MASK(32); 553 pdev->dev.dma_mask = &pdev->platform_dma_mask; 554 } 555 }; 556 557 /** 558 * platform_device_put - destroy a platform device 559 * @pdev: platform device to free 560 * 561 * Free all memory associated with a platform device. This function must 562 * _only_ be externally called in error cases. All other usage is a bug. 563 */ 564 void platform_device_put(struct platform_device *pdev) 565 { 566 if (!IS_ERR_OR_NULL(pdev)) 567 put_device(&pdev->dev); 568 } 569 EXPORT_SYMBOL_GPL(platform_device_put); 570 571 static void platform_device_release(struct device *dev) 572 { 573 struct platform_object *pa = container_of(dev, struct platform_object, 574 pdev.dev); 575 576 of_node_put(pa->pdev.dev.of_node); 577 kfree(pa->pdev.dev.platform_data); 578 kfree(pa->pdev.mfd_cell); 579 kfree(pa->pdev.resource); 580 kfree(pa->pdev.driver_override); 581 kfree(pa); 582 } 583 584 /** 585 * platform_device_alloc - create a platform device 586 * @name: base name of the device we're adding 587 * @id: instance id 588 * 589 * Create a platform device object which can have other objects attached 590 * to it, and which will have attached objects freed when it is released. 591 */ 592 struct platform_device *platform_device_alloc(const char *name, int id) 593 { 594 struct platform_object *pa; 595 596 pa = kzalloc(sizeof(*pa) + strlen(name) + 1, GFP_KERNEL); 597 if (pa) { 598 strcpy(pa->name, name); 599 pa->pdev.name = pa->name; 600 pa->pdev.id = id; 601 device_initialize(&pa->pdev.dev); 602 pa->pdev.dev.release = platform_device_release; 603 setup_pdev_dma_masks(&pa->pdev); 604 } 605 606 return pa ? &pa->pdev : NULL; 607 } 608 EXPORT_SYMBOL_GPL(platform_device_alloc); 609 610 /** 611 * platform_device_add_resources - add resources to a platform device 612 * @pdev: platform device allocated by platform_device_alloc to add resources to 613 * @res: set of resources that needs to be allocated for the device 614 * @num: number of resources 615 * 616 * Add a copy of the resources to the platform device. The memory 617 * associated with the resources will be freed when the platform device is 618 * released. 619 */ 620 int platform_device_add_resources(struct platform_device *pdev, 621 const struct resource *res, unsigned int num) 622 { 623 struct resource *r = NULL; 624 625 if (res) { 626 r = kmemdup(res, sizeof(struct resource) * num, GFP_KERNEL); 627 if (!r) 628 return -ENOMEM; 629 } 630 631 kfree(pdev->resource); 632 pdev->resource = r; 633 pdev->num_resources = num; 634 return 0; 635 } 636 EXPORT_SYMBOL_GPL(platform_device_add_resources); 637 638 /** 639 * platform_device_add_data - add platform-specific data to a platform device 640 * @pdev: platform device allocated by platform_device_alloc to add resources to 641 * @data: platform specific data for this platform device 642 * @size: size of platform specific data 643 * 644 * Add a copy of platform specific data to the platform device's 645 * platform_data pointer. The memory associated with the platform data 646 * will be freed when the platform device is released. 647 */ 648 int platform_device_add_data(struct platform_device *pdev, const void *data, 649 size_t size) 650 { 651 void *d = NULL; 652 653 if (data) { 654 d = kmemdup(data, size, GFP_KERNEL); 655 if (!d) 656 return -ENOMEM; 657 } 658 659 kfree(pdev->dev.platform_data); 660 pdev->dev.platform_data = d; 661 return 0; 662 } 663 EXPORT_SYMBOL_GPL(platform_device_add_data); 664 665 /** 666 * platform_device_add_properties - add built-in properties to a platform device 667 * @pdev: platform device to add properties to 668 * @properties: null terminated array of properties to add 669 * 670 * The function will take deep copy of @properties and attach the copy to the 671 * platform device. The memory associated with properties will be freed when the 672 * platform device is released. 673 */ 674 int platform_device_add_properties(struct platform_device *pdev, 675 const struct property_entry *properties) 676 { 677 return device_add_properties(&pdev->dev, properties); 678 } 679 EXPORT_SYMBOL_GPL(platform_device_add_properties); 680 681 /** 682 * platform_device_add - add a platform device to device hierarchy 683 * @pdev: platform device we're adding 684 * 685 * This is part 2 of platform_device_register(), though may be called 686 * separately _iff_ pdev was allocated by platform_device_alloc(). 687 */ 688 int platform_device_add(struct platform_device *pdev) 689 { 690 u32 i; 691 int ret; 692 693 if (!pdev) 694 return -EINVAL; 695 696 if (!pdev->dev.parent) 697 pdev->dev.parent = &platform_bus; 698 699 pdev->dev.bus = &platform_bus_type; 700 701 switch (pdev->id) { 702 default: 703 dev_set_name(&pdev->dev, "%s.%d", pdev->name, pdev->id); 704 break; 705 case PLATFORM_DEVID_NONE: 706 dev_set_name(&pdev->dev, "%s", pdev->name); 707 break; 708 case PLATFORM_DEVID_AUTO: 709 /* 710 * Automatically allocated device ID. We mark it as such so 711 * that we remember it must be freed, and we append a suffix 712 * to avoid namespace collision with explicit IDs. 713 */ 714 ret = ida_alloc(&platform_devid_ida, GFP_KERNEL); 715 if (ret < 0) 716 goto err_out; 717 pdev->id = ret; 718 pdev->id_auto = true; 719 dev_set_name(&pdev->dev, "%s.%d.auto", pdev->name, pdev->id); 720 break; 721 } 722 723 for (i = 0; i < pdev->num_resources; i++) { 724 struct resource *p, *r = &pdev->resource[i]; 725 726 if (r->name == NULL) 727 r->name = dev_name(&pdev->dev); 728 729 p = r->parent; 730 if (!p) { 731 if (resource_type(r) == IORESOURCE_MEM) 732 p = &iomem_resource; 733 else if (resource_type(r) == IORESOURCE_IO) 734 p = &ioport_resource; 735 } 736 737 if (p) { 738 ret = insert_resource(p, r); 739 if (ret) { 740 dev_err(&pdev->dev, "failed to claim resource %d: %pR\n", i, r); 741 goto failed; 742 } 743 } 744 } 745 746 pr_debug("Registering platform device '%s'. Parent at %s\n", 747 dev_name(&pdev->dev), dev_name(pdev->dev.parent)); 748 749 ret = device_add(&pdev->dev); 750 if (ret == 0) 751 return ret; 752 753 failed: 754 if (pdev->id_auto) { 755 ida_free(&platform_devid_ida, pdev->id); 756 pdev->id = PLATFORM_DEVID_AUTO; 757 } 758 759 while (i--) { 760 struct resource *r = &pdev->resource[i]; 761 if (r->parent) 762 release_resource(r); 763 } 764 765 err_out: 766 return ret; 767 } 768 EXPORT_SYMBOL_GPL(platform_device_add); 769 770 /** 771 * platform_device_del - remove a platform-level device 772 * @pdev: platform device we're removing 773 * 774 * Note that this function will also release all memory- and port-based 775 * resources owned by the device (@dev->resource). This function must 776 * _only_ be externally called in error cases. All other usage is a bug. 777 */ 778 void platform_device_del(struct platform_device *pdev) 779 { 780 u32 i; 781 782 if (!IS_ERR_OR_NULL(pdev)) { 783 device_del(&pdev->dev); 784 785 if (pdev->id_auto) { 786 ida_free(&platform_devid_ida, pdev->id); 787 pdev->id = PLATFORM_DEVID_AUTO; 788 } 789 790 for (i = 0; i < pdev->num_resources; i++) { 791 struct resource *r = &pdev->resource[i]; 792 if (r->parent) 793 release_resource(r); 794 } 795 } 796 } 797 EXPORT_SYMBOL_GPL(platform_device_del); 798 799 /** 800 * platform_device_register - add a platform-level device 801 * @pdev: platform device we're adding 802 */ 803 int platform_device_register(struct platform_device *pdev) 804 { 805 device_initialize(&pdev->dev); 806 setup_pdev_dma_masks(pdev); 807 return platform_device_add(pdev); 808 } 809 EXPORT_SYMBOL_GPL(platform_device_register); 810 811 /** 812 * platform_device_unregister - unregister a platform-level device 813 * @pdev: platform device we're unregistering 814 * 815 * Unregistration is done in 2 steps. First we release all resources 816 * and remove it from the subsystem, then we drop reference count by 817 * calling platform_device_put(). 818 */ 819 void platform_device_unregister(struct platform_device *pdev) 820 { 821 platform_device_del(pdev); 822 platform_device_put(pdev); 823 } 824 EXPORT_SYMBOL_GPL(platform_device_unregister); 825 826 /** 827 * platform_device_register_full - add a platform-level device with 828 * resources and platform-specific data 829 * 830 * @pdevinfo: data used to create device 831 * 832 * Returns &struct platform_device pointer on success, or ERR_PTR() on error. 833 */ 834 struct platform_device *platform_device_register_full( 835 const struct platform_device_info *pdevinfo) 836 { 837 int ret; 838 struct platform_device *pdev; 839 840 pdev = platform_device_alloc(pdevinfo->name, pdevinfo->id); 841 if (!pdev) 842 return ERR_PTR(-ENOMEM); 843 844 pdev->dev.parent = pdevinfo->parent; 845 pdev->dev.fwnode = pdevinfo->fwnode; 846 pdev->dev.of_node = of_node_get(to_of_node(pdev->dev.fwnode)); 847 pdev->dev.of_node_reused = pdevinfo->of_node_reused; 848 849 if (pdevinfo->dma_mask) { 850 pdev->platform_dma_mask = pdevinfo->dma_mask; 851 pdev->dev.dma_mask = &pdev->platform_dma_mask; 852 pdev->dev.coherent_dma_mask = pdevinfo->dma_mask; 853 } 854 855 ret = platform_device_add_resources(pdev, 856 pdevinfo->res, pdevinfo->num_res); 857 if (ret) 858 goto err; 859 860 ret = platform_device_add_data(pdev, 861 pdevinfo->data, pdevinfo->size_data); 862 if (ret) 863 goto err; 864 865 if (pdevinfo->properties) { 866 ret = platform_device_add_properties(pdev, 867 pdevinfo->properties); 868 if (ret) 869 goto err; 870 } 871 872 ret = platform_device_add(pdev); 873 if (ret) { 874 err: 875 ACPI_COMPANION_SET(&pdev->dev, NULL); 876 platform_device_put(pdev); 877 return ERR_PTR(ret); 878 } 879 880 return pdev; 881 } 882 EXPORT_SYMBOL_GPL(platform_device_register_full); 883 884 /** 885 * __platform_driver_register - register a driver for platform-level devices 886 * @drv: platform driver structure 887 * @owner: owning module/driver 888 */ 889 int __platform_driver_register(struct platform_driver *drv, 890 struct module *owner) 891 { 892 drv->driver.owner = owner; 893 drv->driver.bus = &platform_bus_type; 894 895 return driver_register(&drv->driver); 896 } 897 EXPORT_SYMBOL_GPL(__platform_driver_register); 898 899 /** 900 * platform_driver_unregister - unregister a driver for platform-level devices 901 * @drv: platform driver structure 902 */ 903 void platform_driver_unregister(struct platform_driver *drv) 904 { 905 driver_unregister(&drv->driver); 906 } 907 EXPORT_SYMBOL_GPL(platform_driver_unregister); 908 909 static int platform_probe_fail(struct platform_device *pdev) 910 { 911 return -ENXIO; 912 } 913 914 /** 915 * __platform_driver_probe - register driver for non-hotpluggable device 916 * @drv: platform driver structure 917 * @probe: the driver probe routine, probably from an __init section 918 * @module: module which will be the owner of the driver 919 * 920 * Use this instead of platform_driver_register() when you know the device 921 * is not hotpluggable and has already been registered, and you want to 922 * remove its run-once probe() infrastructure from memory after the driver 923 * has bound to the device. 924 * 925 * One typical use for this would be with drivers for controllers integrated 926 * into system-on-chip processors, where the controller devices have been 927 * configured as part of board setup. 928 * 929 * Note that this is incompatible with deferred probing. 930 * 931 * Returns zero if the driver registered and bound to a device, else returns 932 * a negative error code and with the driver not registered. 933 */ 934 int __init_or_module __platform_driver_probe(struct platform_driver *drv, 935 int (*probe)(struct platform_device *), struct module *module) 936 { 937 int retval, code; 938 939 if (drv->driver.probe_type == PROBE_PREFER_ASYNCHRONOUS) { 940 pr_err("%s: drivers registered with %s can not be probed asynchronously\n", 941 drv->driver.name, __func__); 942 return -EINVAL; 943 } 944 945 /* 946 * We have to run our probes synchronously because we check if 947 * we find any devices to bind to and exit with error if there 948 * are any. 949 */ 950 drv->driver.probe_type = PROBE_FORCE_SYNCHRONOUS; 951 952 /* 953 * Prevent driver from requesting probe deferral to avoid further 954 * futile probe attempts. 955 */ 956 drv->prevent_deferred_probe = true; 957 958 /* make sure driver won't have bind/unbind attributes */ 959 drv->driver.suppress_bind_attrs = true; 960 961 /* temporary section violation during probe() */ 962 drv->probe = probe; 963 retval = code = __platform_driver_register(drv, module); 964 if (retval) 965 return retval; 966 967 /* 968 * Fixup that section violation, being paranoid about code scanning 969 * the list of drivers in order to probe new devices. Check to see 970 * if the probe was successful, and make sure any forced probes of 971 * new devices fail. 972 */ 973 spin_lock(&drv->driver.bus->p->klist_drivers.k_lock); 974 drv->probe = platform_probe_fail; 975 if (code == 0 && list_empty(&drv->driver.p->klist_devices.k_list)) 976 retval = -ENODEV; 977 spin_unlock(&drv->driver.bus->p->klist_drivers.k_lock); 978 979 if (code != retval) 980 platform_driver_unregister(drv); 981 return retval; 982 } 983 EXPORT_SYMBOL_GPL(__platform_driver_probe); 984 985 /** 986 * __platform_create_bundle - register driver and create corresponding device 987 * @driver: platform driver structure 988 * @probe: the driver probe routine, probably from an __init section 989 * @res: set of resources that needs to be allocated for the device 990 * @n_res: number of resources 991 * @data: platform specific data for this platform device 992 * @size: size of platform specific data 993 * @module: module which will be the owner of the driver 994 * 995 * Use this in legacy-style modules that probe hardware directly and 996 * register a single platform device and corresponding platform driver. 997 * 998 * Returns &struct platform_device pointer on success, or ERR_PTR() on error. 999 */ 1000 struct platform_device * __init_or_module __platform_create_bundle( 1001 struct platform_driver *driver, 1002 int (*probe)(struct platform_device *), 1003 struct resource *res, unsigned int n_res, 1004 const void *data, size_t size, struct module *module) 1005 { 1006 struct platform_device *pdev; 1007 int error; 1008 1009 pdev = platform_device_alloc(driver->driver.name, -1); 1010 if (!pdev) { 1011 error = -ENOMEM; 1012 goto err_out; 1013 } 1014 1015 error = platform_device_add_resources(pdev, res, n_res); 1016 if (error) 1017 goto err_pdev_put; 1018 1019 error = platform_device_add_data(pdev, data, size); 1020 if (error) 1021 goto err_pdev_put; 1022 1023 error = platform_device_add(pdev); 1024 if (error) 1025 goto err_pdev_put; 1026 1027 error = __platform_driver_probe(driver, probe, module); 1028 if (error) 1029 goto err_pdev_del; 1030 1031 return pdev; 1032 1033 err_pdev_del: 1034 platform_device_del(pdev); 1035 err_pdev_put: 1036 platform_device_put(pdev); 1037 err_out: 1038 return ERR_PTR(error); 1039 } 1040 EXPORT_SYMBOL_GPL(__platform_create_bundle); 1041 1042 /** 1043 * __platform_register_drivers - register an array of platform drivers 1044 * @drivers: an array of drivers to register 1045 * @count: the number of drivers to register 1046 * @owner: module owning the drivers 1047 * 1048 * Registers platform drivers specified by an array. On failure to register a 1049 * driver, all previously registered drivers will be unregistered. Callers of 1050 * this API should use platform_unregister_drivers() to unregister drivers in 1051 * the reverse order. 1052 * 1053 * Returns: 0 on success or a negative error code on failure. 1054 */ 1055 int __platform_register_drivers(struct platform_driver * const *drivers, 1056 unsigned int count, struct module *owner) 1057 { 1058 unsigned int i; 1059 int err; 1060 1061 for (i = 0; i < count; i++) { 1062 pr_debug("registering platform driver %ps\n", drivers[i]); 1063 1064 err = __platform_driver_register(drivers[i], owner); 1065 if (err < 0) { 1066 pr_err("failed to register platform driver %ps: %d\n", 1067 drivers[i], err); 1068 goto error; 1069 } 1070 } 1071 1072 return 0; 1073 1074 error: 1075 while (i--) { 1076 pr_debug("unregistering platform driver %ps\n", drivers[i]); 1077 platform_driver_unregister(drivers[i]); 1078 } 1079 1080 return err; 1081 } 1082 EXPORT_SYMBOL_GPL(__platform_register_drivers); 1083 1084 /** 1085 * platform_unregister_drivers - unregister an array of platform drivers 1086 * @drivers: an array of drivers to unregister 1087 * @count: the number of drivers to unregister 1088 * 1089 * Unregisters platform drivers specified by an array. This is typically used 1090 * to complement an earlier call to platform_register_drivers(). Drivers are 1091 * unregistered in the reverse order in which they were registered. 1092 */ 1093 void platform_unregister_drivers(struct platform_driver * const *drivers, 1094 unsigned int count) 1095 { 1096 while (count--) { 1097 pr_debug("unregistering platform driver %ps\n", drivers[count]); 1098 platform_driver_unregister(drivers[count]); 1099 } 1100 } 1101 EXPORT_SYMBOL_GPL(platform_unregister_drivers); 1102 1103 static const struct platform_device_id *platform_match_id( 1104 const struct platform_device_id *id, 1105 struct platform_device *pdev) 1106 { 1107 while (id->name[0]) { 1108 if (strcmp(pdev->name, id->name) == 0) { 1109 pdev->id_entry = id; 1110 return id; 1111 } 1112 id++; 1113 } 1114 return NULL; 1115 } 1116 1117 #ifdef CONFIG_PM_SLEEP 1118 1119 static int platform_legacy_suspend(struct device *dev, pm_message_t mesg) 1120 { 1121 struct platform_driver *pdrv = to_platform_driver(dev->driver); 1122 struct platform_device *pdev = to_platform_device(dev); 1123 int ret = 0; 1124 1125 if (dev->driver && pdrv->suspend) 1126 ret = pdrv->suspend(pdev, mesg); 1127 1128 return ret; 1129 } 1130 1131 static int platform_legacy_resume(struct device *dev) 1132 { 1133 struct platform_driver *pdrv = to_platform_driver(dev->driver); 1134 struct platform_device *pdev = to_platform_device(dev); 1135 int ret = 0; 1136 1137 if (dev->driver && pdrv->resume) 1138 ret = pdrv->resume(pdev); 1139 1140 return ret; 1141 } 1142 1143 #endif /* CONFIG_PM_SLEEP */ 1144 1145 #ifdef CONFIG_SUSPEND 1146 1147 int platform_pm_suspend(struct device *dev) 1148 { 1149 struct device_driver *drv = dev->driver; 1150 int ret = 0; 1151 1152 if (!drv) 1153 return 0; 1154 1155 if (drv->pm) { 1156 if (drv->pm->suspend) 1157 ret = drv->pm->suspend(dev); 1158 } else { 1159 ret = platform_legacy_suspend(dev, PMSG_SUSPEND); 1160 } 1161 1162 return ret; 1163 } 1164 1165 int platform_pm_resume(struct device *dev) 1166 { 1167 struct device_driver *drv = dev->driver; 1168 int ret = 0; 1169 1170 if (!drv) 1171 return 0; 1172 1173 if (drv->pm) { 1174 if (drv->pm->resume) 1175 ret = drv->pm->resume(dev); 1176 } else { 1177 ret = platform_legacy_resume(dev); 1178 } 1179 1180 return ret; 1181 } 1182 1183 #endif /* CONFIG_SUSPEND */ 1184 1185 #ifdef CONFIG_HIBERNATE_CALLBACKS 1186 1187 int platform_pm_freeze(struct device *dev) 1188 { 1189 struct device_driver *drv = dev->driver; 1190 int ret = 0; 1191 1192 if (!drv) 1193 return 0; 1194 1195 if (drv->pm) { 1196 if (drv->pm->freeze) 1197 ret = drv->pm->freeze(dev); 1198 } else { 1199 ret = platform_legacy_suspend(dev, PMSG_FREEZE); 1200 } 1201 1202 return ret; 1203 } 1204 1205 int platform_pm_thaw(struct device *dev) 1206 { 1207 struct device_driver *drv = dev->driver; 1208 int ret = 0; 1209 1210 if (!drv) 1211 return 0; 1212 1213 if (drv->pm) { 1214 if (drv->pm->thaw) 1215 ret = drv->pm->thaw(dev); 1216 } else { 1217 ret = platform_legacy_resume(dev); 1218 } 1219 1220 return ret; 1221 } 1222 1223 int platform_pm_poweroff(struct device *dev) 1224 { 1225 struct device_driver *drv = dev->driver; 1226 int ret = 0; 1227 1228 if (!drv) 1229 return 0; 1230 1231 if (drv->pm) { 1232 if (drv->pm->poweroff) 1233 ret = drv->pm->poweroff(dev); 1234 } else { 1235 ret = platform_legacy_suspend(dev, PMSG_HIBERNATE); 1236 } 1237 1238 return ret; 1239 } 1240 1241 int platform_pm_restore(struct device *dev) 1242 { 1243 struct device_driver *drv = dev->driver; 1244 int ret = 0; 1245 1246 if (!drv) 1247 return 0; 1248 1249 if (drv->pm) { 1250 if (drv->pm->restore) 1251 ret = drv->pm->restore(dev); 1252 } else { 1253 ret = platform_legacy_resume(dev); 1254 } 1255 1256 return ret; 1257 } 1258 1259 #endif /* CONFIG_HIBERNATE_CALLBACKS */ 1260 1261 /* modalias support enables more hands-off userspace setup: 1262 * (a) environment variable lets new-style hotplug events work once system is 1263 * fully running: "modprobe $MODALIAS" 1264 * (b) sysfs attribute lets new-style coldplug recover from hotplug events 1265 * mishandled before system is fully running: "modprobe $(cat modalias)" 1266 */ 1267 static ssize_t modalias_show(struct device *dev, 1268 struct device_attribute *attr, char *buf) 1269 { 1270 struct platform_device *pdev = to_platform_device(dev); 1271 int len; 1272 1273 len = of_device_modalias(dev, buf, PAGE_SIZE); 1274 if (len != -ENODEV) 1275 return len; 1276 1277 len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1); 1278 if (len != -ENODEV) 1279 return len; 1280 1281 return sysfs_emit(buf, "platform:%s\n", pdev->name); 1282 } 1283 static DEVICE_ATTR_RO(modalias); 1284 1285 static ssize_t numa_node_show(struct device *dev, 1286 struct device_attribute *attr, char *buf) 1287 { 1288 return sysfs_emit(buf, "%d\n", dev_to_node(dev)); 1289 } 1290 static DEVICE_ATTR_RO(numa_node); 1291 1292 static ssize_t driver_override_show(struct device *dev, 1293 struct device_attribute *attr, char *buf) 1294 { 1295 struct platform_device *pdev = to_platform_device(dev); 1296 ssize_t len; 1297 1298 device_lock(dev); 1299 len = sysfs_emit(buf, "%s\n", pdev->driver_override); 1300 device_unlock(dev); 1301 1302 return len; 1303 } 1304 1305 static ssize_t driver_override_store(struct device *dev, 1306 struct device_attribute *attr, 1307 const char *buf, size_t count) 1308 { 1309 struct platform_device *pdev = to_platform_device(dev); 1310 char *driver_override, *old, *cp; 1311 1312 /* We need to keep extra room for a newline */ 1313 if (count >= (PAGE_SIZE - 1)) 1314 return -EINVAL; 1315 1316 driver_override = kstrndup(buf, count, GFP_KERNEL); 1317 if (!driver_override) 1318 return -ENOMEM; 1319 1320 cp = strchr(driver_override, '\n'); 1321 if (cp) 1322 *cp = '\0'; 1323 1324 device_lock(dev); 1325 old = pdev->driver_override; 1326 if (strlen(driver_override)) { 1327 pdev->driver_override = driver_override; 1328 } else { 1329 kfree(driver_override); 1330 pdev->driver_override = NULL; 1331 } 1332 device_unlock(dev); 1333 1334 kfree(old); 1335 1336 return count; 1337 } 1338 static DEVICE_ATTR_RW(driver_override); 1339 1340 static struct attribute *platform_dev_attrs[] = { 1341 &dev_attr_modalias.attr, 1342 &dev_attr_numa_node.attr, 1343 &dev_attr_driver_override.attr, 1344 NULL, 1345 }; 1346 1347 static umode_t platform_dev_attrs_visible(struct kobject *kobj, struct attribute *a, 1348 int n) 1349 { 1350 struct device *dev = container_of(kobj, typeof(*dev), kobj); 1351 1352 if (a == &dev_attr_numa_node.attr && 1353 dev_to_node(dev) == NUMA_NO_NODE) 1354 return 0; 1355 1356 return a->mode; 1357 } 1358 1359 static struct attribute_group platform_dev_group = { 1360 .attrs = platform_dev_attrs, 1361 .is_visible = platform_dev_attrs_visible, 1362 }; 1363 __ATTRIBUTE_GROUPS(platform_dev); 1364 1365 1366 /** 1367 * platform_match - bind platform device to platform driver. 1368 * @dev: device. 1369 * @drv: driver. 1370 * 1371 * Platform device IDs are assumed to be encoded like this: 1372 * "<name><instance>", where <name> is a short description of the type of 1373 * device, like "pci" or "floppy", and <instance> is the enumerated 1374 * instance of the device, like '0' or '42'. Driver IDs are simply 1375 * "<name>". So, extract the <name> from the platform_device structure, 1376 * and compare it against the name of the driver. Return whether they match 1377 * or not. 1378 */ 1379 static int platform_match(struct device *dev, struct device_driver *drv) 1380 { 1381 struct platform_device *pdev = to_platform_device(dev); 1382 struct platform_driver *pdrv = to_platform_driver(drv); 1383 1384 /* When driver_override is set, only bind to the matching driver */ 1385 if (pdev->driver_override) 1386 return !strcmp(pdev->driver_override, drv->name); 1387 1388 /* Attempt an OF style match first */ 1389 if (of_driver_match_device(dev, drv)) 1390 return 1; 1391 1392 /* Then try ACPI style match */ 1393 if (acpi_driver_match_device(dev, drv)) 1394 return 1; 1395 1396 /* Then try to match against the id table */ 1397 if (pdrv->id_table) 1398 return platform_match_id(pdrv->id_table, pdev) != NULL; 1399 1400 /* fall-back to driver name match */ 1401 return (strcmp(pdev->name, drv->name) == 0); 1402 } 1403 1404 static int platform_uevent(struct device *dev, struct kobj_uevent_env *env) 1405 { 1406 struct platform_device *pdev = to_platform_device(dev); 1407 int rc; 1408 1409 /* Some devices have extra OF data and an OF-style MODALIAS */ 1410 rc = of_device_uevent_modalias(dev, env); 1411 if (rc != -ENODEV) 1412 return rc; 1413 1414 rc = acpi_device_uevent_modalias(dev, env); 1415 if (rc != -ENODEV) 1416 return rc; 1417 1418 add_uevent_var(env, "MODALIAS=%s%s", PLATFORM_MODULE_PREFIX, 1419 pdev->name); 1420 return 0; 1421 } 1422 1423 static int platform_probe(struct device *_dev) 1424 { 1425 struct platform_driver *drv = to_platform_driver(_dev->driver); 1426 struct platform_device *dev = to_platform_device(_dev); 1427 int ret; 1428 1429 /* 1430 * A driver registered using platform_driver_probe() cannot be bound 1431 * again later because the probe function usually lives in __init code 1432 * and so is gone. For these drivers .probe is set to 1433 * platform_probe_fail in __platform_driver_probe(). Don't even prepare 1434 * clocks and PM domains for these to match the traditional behaviour. 1435 */ 1436 if (unlikely(drv->probe == platform_probe_fail)) 1437 return -ENXIO; 1438 1439 ret = of_clk_set_defaults(_dev->of_node, false); 1440 if (ret < 0) 1441 return ret; 1442 1443 ret = dev_pm_domain_attach(_dev, true); 1444 if (ret) 1445 goto out; 1446 1447 if (drv->probe) { 1448 ret = drv->probe(dev); 1449 if (ret) 1450 dev_pm_domain_detach(_dev, true); 1451 } 1452 1453 out: 1454 if (drv->prevent_deferred_probe && ret == -EPROBE_DEFER) { 1455 dev_warn(_dev, "probe deferral not supported\n"); 1456 ret = -ENXIO; 1457 } 1458 1459 return ret; 1460 } 1461 1462 static int platform_remove(struct device *_dev) 1463 { 1464 struct platform_driver *drv = to_platform_driver(_dev->driver); 1465 struct platform_device *dev = to_platform_device(_dev); 1466 1467 if (drv->remove) { 1468 int ret = drv->remove(dev); 1469 1470 if (ret) 1471 dev_warn(_dev, "remove callback returned a non-zero value. This will be ignored.\n"); 1472 } 1473 dev_pm_domain_detach(_dev, true); 1474 1475 return 0; 1476 } 1477 1478 static void platform_shutdown(struct device *_dev) 1479 { 1480 struct platform_device *dev = to_platform_device(_dev); 1481 struct platform_driver *drv; 1482 1483 if (!_dev->driver) 1484 return; 1485 1486 drv = to_platform_driver(_dev->driver); 1487 if (drv->shutdown) 1488 drv->shutdown(dev); 1489 } 1490 1491 1492 int platform_dma_configure(struct device *dev) 1493 { 1494 enum dev_dma_attr attr; 1495 int ret = 0; 1496 1497 if (dev->of_node) { 1498 ret = of_dma_configure(dev, dev->of_node, true); 1499 } else if (has_acpi_companion(dev)) { 1500 attr = acpi_get_dma_attr(to_acpi_device_node(dev->fwnode)); 1501 ret = acpi_dma_configure(dev, attr); 1502 } 1503 1504 return ret; 1505 } 1506 1507 static const struct dev_pm_ops platform_dev_pm_ops = { 1508 .runtime_suspend = pm_generic_runtime_suspend, 1509 .runtime_resume = pm_generic_runtime_resume, 1510 USE_PLATFORM_PM_SLEEP_OPS 1511 }; 1512 1513 struct bus_type platform_bus_type = { 1514 .name = "platform", 1515 .dev_groups = platform_dev_groups, 1516 .match = platform_match, 1517 .uevent = platform_uevent, 1518 .probe = platform_probe, 1519 .remove = platform_remove, 1520 .shutdown = platform_shutdown, 1521 .dma_configure = platform_dma_configure, 1522 .pm = &platform_dev_pm_ops, 1523 }; 1524 EXPORT_SYMBOL_GPL(platform_bus_type); 1525 1526 static inline int __platform_match(struct device *dev, const void *drv) 1527 { 1528 return platform_match(dev, (struct device_driver *)drv); 1529 } 1530 1531 /** 1532 * platform_find_device_by_driver - Find a platform device with a given 1533 * driver. 1534 * @start: The device to start the search from. 1535 * @drv: The device driver to look for. 1536 */ 1537 struct device *platform_find_device_by_driver(struct device *start, 1538 const struct device_driver *drv) 1539 { 1540 return bus_find_device(&platform_bus_type, start, drv, 1541 __platform_match); 1542 } 1543 EXPORT_SYMBOL_GPL(platform_find_device_by_driver); 1544 1545 void __weak __init early_platform_cleanup(void) { } 1546 1547 int __init platform_bus_init(void) 1548 { 1549 int error; 1550 1551 early_platform_cleanup(); 1552 1553 error = device_register(&platform_bus); 1554 if (error) { 1555 put_device(&platform_bus); 1556 return error; 1557 } 1558 error = bus_register(&platform_bus_type); 1559 if (error) 1560 device_unregister(&platform_bus); 1561 of_platform_register_reconfig_notifier(); 1562 return error; 1563 } 1564