xref: /openbmc/linux/drivers/of/platform.c (revision 39f555fb)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  *    Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corp.
4  *			 <benh@kernel.crashing.org>
5  *    and		 Arnd Bergmann, IBM Corp.
6  *    Merged from powerpc/kernel/of_platform.c and
7  *    sparc{,64}/kernel/of_device.c by Stephen Rothwell
8  */
9 
10 #define pr_fmt(fmt)	"OF: " fmt
11 
12 #include <linux/errno.h>
13 #include <linux/module.h>
14 #include <linux/amba/bus.h>
15 #include <linux/device.h>
16 #include <linux/dma-mapping.h>
17 #include <linux/slab.h>
18 #include <linux/of_address.h>
19 #include <linux/of_device.h>
20 #include <linux/of_irq.h>
21 #include <linux/of_platform.h>
22 #include <linux/platform_device.h>
23 
24 #include "of_private.h"
25 
26 const struct of_device_id of_default_bus_match_table[] = {
27 	{ .compatible = "simple-bus", },
28 	{ .compatible = "simple-mfd", },
29 	{ .compatible = "isa", },
30 #ifdef CONFIG_ARM_AMBA
31 	{ .compatible = "arm,amba-bus", },
32 #endif /* CONFIG_ARM_AMBA */
33 	{} /* Empty terminated list */
34 };
35 
36 /**
37  * of_find_device_by_node - Find the platform_device associated with a node
38  * @np: Pointer to device tree node
39  *
40  * Takes a reference to the embedded struct device which needs to be dropped
41  * after use.
42  *
43  * Return: platform_device pointer, or NULL if not found
44  */
45 struct platform_device *of_find_device_by_node(struct device_node *np)
46 {
47 	struct device *dev;
48 
49 	dev = bus_find_device_by_of_node(&platform_bus_type, np);
50 	return dev ? to_platform_device(dev) : NULL;
51 }
52 EXPORT_SYMBOL(of_find_device_by_node);
53 
54 int of_device_add(struct platform_device *ofdev)
55 {
56 	BUG_ON(ofdev->dev.of_node == NULL);
57 
58 	/* name and id have to be set so that the platform bus doesn't get
59 	 * confused on matching */
60 	ofdev->name = dev_name(&ofdev->dev);
61 	ofdev->id = PLATFORM_DEVID_NONE;
62 
63 	/*
64 	 * If this device has not binding numa node in devicetree, that is
65 	 * of_node_to_nid returns NUMA_NO_NODE. device_add will assume that this
66 	 * device is on the same node as the parent.
67 	 */
68 	set_dev_node(&ofdev->dev, of_node_to_nid(ofdev->dev.of_node));
69 
70 	return device_add(&ofdev->dev);
71 }
72 
73 int of_device_register(struct platform_device *pdev)
74 {
75 	device_initialize(&pdev->dev);
76 	return of_device_add(pdev);
77 }
78 EXPORT_SYMBOL(of_device_register);
79 
80 void of_device_unregister(struct platform_device *ofdev)
81 {
82 	device_unregister(&ofdev->dev);
83 }
84 EXPORT_SYMBOL(of_device_unregister);
85 
86 #ifdef CONFIG_OF_ADDRESS
87 static const struct of_device_id of_skipped_node_table[] = {
88 	{ .compatible = "operating-points-v2", },
89 	{} /* Empty terminated list */
90 };
91 
92 /*
93  * The following routines scan a subtree and registers a device for
94  * each applicable node.
95  *
96  * Note: sparc doesn't use these routines because it has a different
97  * mechanism for creating devices from device tree nodes.
98  */
99 
100 /**
101  * of_device_make_bus_id - Use the device node data to assign a unique name
102  * @dev: pointer to device structure that is linked to a device tree node
103  *
104  * This routine will first try using the translated bus address to
105  * derive a unique name. If it cannot, then it will prepend names from
106  * parent nodes until a unique name can be derived.
107  */
108 static void of_device_make_bus_id(struct device *dev)
109 {
110 	struct device_node *node = dev->of_node;
111 	const __be32 *reg;
112 	u64 addr;
113 	u32 mask;
114 
115 	/* Construct the name, using parent nodes if necessary to ensure uniqueness */
116 	while (node->parent) {
117 		/*
118 		 * If the address can be translated, then that is as much
119 		 * uniqueness as we need. Make it the first component and return
120 		 */
121 		reg = of_get_property(node, "reg", NULL);
122 		if (reg && (addr = of_translate_address(node, reg)) != OF_BAD_ADDR) {
123 			if (!of_property_read_u32(node, "mask", &mask))
124 				dev_set_name(dev, dev_name(dev) ? "%llx.%x.%pOFn:%s" : "%llx.%x.%pOFn",
125 					     addr, ffs(mask) - 1, node, dev_name(dev));
126 
127 			else
128 				dev_set_name(dev, dev_name(dev) ? "%llx.%pOFn:%s" : "%llx.%pOFn",
129 					     addr, node, dev_name(dev));
130 			return;
131 		}
132 
133 		/* format arguments only used if dev_name() resolves to NULL */
134 		dev_set_name(dev, dev_name(dev) ? "%s:%s" : "%s",
135 			     kbasename(node->full_name), dev_name(dev));
136 		node = node->parent;
137 	}
138 }
139 
140 /**
141  * of_device_alloc - Allocate and initialize an of_device
142  * @np: device node to assign to device
143  * @bus_id: Name to assign to the device.  May be null to use default name.
144  * @parent: Parent device.
145  */
146 struct platform_device *of_device_alloc(struct device_node *np,
147 				  const char *bus_id,
148 				  struct device *parent)
149 {
150 	struct platform_device *dev;
151 	int rc, i, num_reg = 0;
152 	struct resource *res;
153 
154 	dev = platform_device_alloc("", PLATFORM_DEVID_NONE);
155 	if (!dev)
156 		return NULL;
157 
158 	/* count the io resources */
159 	num_reg = of_address_count(np);
160 
161 	/* Populate the resource table */
162 	if (num_reg) {
163 		res = kcalloc(num_reg, sizeof(*res), GFP_KERNEL);
164 		if (!res) {
165 			platform_device_put(dev);
166 			return NULL;
167 		}
168 
169 		dev->num_resources = num_reg;
170 		dev->resource = res;
171 		for (i = 0; i < num_reg; i++, res++) {
172 			rc = of_address_to_resource(np, i, res);
173 			WARN_ON(rc);
174 		}
175 	}
176 
177 	/* setup generic device info */
178 	device_set_node(&dev->dev, of_fwnode_handle(of_node_get(np)));
179 	dev->dev.parent = parent ? : &platform_bus;
180 
181 	if (bus_id)
182 		dev_set_name(&dev->dev, "%s", bus_id);
183 	else
184 		of_device_make_bus_id(&dev->dev);
185 
186 	return dev;
187 }
188 EXPORT_SYMBOL(of_device_alloc);
189 
190 /**
191  * of_platform_device_create_pdata - Alloc, initialize and register an of_device
192  * @np: pointer to node to create device for
193  * @bus_id: name to assign device
194  * @platform_data: pointer to populate platform_data pointer with
195  * @parent: Linux device model parent device.
196  *
197  * Return: Pointer to created platform device, or NULL if a device was not
198  * registered.  Unavailable devices will not get registered.
199  */
200 static struct platform_device *of_platform_device_create_pdata(
201 					struct device_node *np,
202 					const char *bus_id,
203 					void *platform_data,
204 					struct device *parent)
205 {
206 	struct platform_device *dev;
207 
208 	if (!of_device_is_available(np) ||
209 	    of_node_test_and_set_flag(np, OF_POPULATED))
210 		return NULL;
211 
212 	dev = of_device_alloc(np, bus_id, parent);
213 	if (!dev)
214 		goto err_clear_flag;
215 
216 	dev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
217 	if (!dev->dev.dma_mask)
218 		dev->dev.dma_mask = &dev->dev.coherent_dma_mask;
219 	dev->dev.bus = &platform_bus_type;
220 	dev->dev.platform_data = platform_data;
221 	of_msi_configure(&dev->dev, dev->dev.of_node);
222 
223 	if (of_device_add(dev) != 0) {
224 		platform_device_put(dev);
225 		goto err_clear_flag;
226 	}
227 
228 	return dev;
229 
230 err_clear_flag:
231 	of_node_clear_flag(np, OF_POPULATED);
232 	return NULL;
233 }
234 
235 /**
236  * of_platform_device_create - Alloc, initialize and register an of_device
237  * @np: pointer to node to create device for
238  * @bus_id: name to assign device
239  * @parent: Linux device model parent device.
240  *
241  * Return: Pointer to created platform device, or NULL if a device was not
242  * registered.  Unavailable devices will not get registered.
243  */
244 struct platform_device *of_platform_device_create(struct device_node *np,
245 					    const char *bus_id,
246 					    struct device *parent)
247 {
248 	return of_platform_device_create_pdata(np, bus_id, NULL, parent);
249 }
250 EXPORT_SYMBOL(of_platform_device_create);
251 
252 #ifdef CONFIG_ARM_AMBA
253 static struct amba_device *of_amba_device_create(struct device_node *node,
254 						 const char *bus_id,
255 						 void *platform_data,
256 						 struct device *parent)
257 {
258 	struct amba_device *dev;
259 	int ret;
260 
261 	pr_debug("Creating amba device %pOF\n", node);
262 
263 	if (!of_device_is_available(node) ||
264 	    of_node_test_and_set_flag(node, OF_POPULATED))
265 		return NULL;
266 
267 	dev = amba_device_alloc(NULL, 0, 0);
268 	if (!dev)
269 		goto err_clear_flag;
270 
271 	/* AMBA devices only support a single DMA mask */
272 	dev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
273 	dev->dev.dma_mask = &dev->dev.coherent_dma_mask;
274 
275 	/* setup generic device info */
276 	device_set_node(&dev->dev, of_fwnode_handle(of_node_get(node)));
277 	dev->dev.parent = parent ? : &platform_bus;
278 	dev->dev.platform_data = platform_data;
279 	if (bus_id)
280 		dev_set_name(&dev->dev, "%s", bus_id);
281 	else
282 		of_device_make_bus_id(&dev->dev);
283 
284 	/* Allow the HW Peripheral ID to be overridden */
285 	of_property_read_u32(node, "arm,primecell-periphid", &dev->periphid);
286 
287 	ret = of_address_to_resource(node, 0, &dev->res);
288 	if (ret) {
289 		pr_err("amba: of_address_to_resource() failed (%d) for %pOF\n",
290 		       ret, node);
291 		goto err_free;
292 	}
293 
294 	ret = amba_device_add(dev, &iomem_resource);
295 	if (ret) {
296 		pr_err("amba_device_add() failed (%d) for %pOF\n",
297 		       ret, node);
298 		goto err_free;
299 	}
300 
301 	return dev;
302 
303 err_free:
304 	amba_device_put(dev);
305 err_clear_flag:
306 	of_node_clear_flag(node, OF_POPULATED);
307 	return NULL;
308 }
309 #else /* CONFIG_ARM_AMBA */
310 static struct amba_device *of_amba_device_create(struct device_node *node,
311 						 const char *bus_id,
312 						 void *platform_data,
313 						 struct device *parent)
314 {
315 	return NULL;
316 }
317 #endif /* CONFIG_ARM_AMBA */
318 
319 /*
320  * of_dev_lookup() - Given a device node, lookup the preferred Linux name
321  */
322 static const struct of_dev_auxdata *of_dev_lookup(const struct of_dev_auxdata *lookup,
323 				 struct device_node *np)
324 {
325 	const struct of_dev_auxdata *auxdata;
326 	struct resource res;
327 	int compatible = 0;
328 
329 	if (!lookup)
330 		return NULL;
331 
332 	auxdata = lookup;
333 	for (; auxdata->compatible; auxdata++) {
334 		if (!of_device_is_compatible(np, auxdata->compatible))
335 			continue;
336 		compatible++;
337 		if (!of_address_to_resource(np, 0, &res))
338 			if (res.start != auxdata->phys_addr)
339 				continue;
340 		pr_debug("%pOF: devname=%s\n", np, auxdata->name);
341 		return auxdata;
342 	}
343 
344 	if (!compatible)
345 		return NULL;
346 
347 	/* Try compatible match if no phys_addr and name are specified */
348 	auxdata = lookup;
349 	for (; auxdata->compatible; auxdata++) {
350 		if (!of_device_is_compatible(np, auxdata->compatible))
351 			continue;
352 		if (!auxdata->phys_addr && !auxdata->name) {
353 			pr_debug("%pOF: compatible match\n", np);
354 			return auxdata;
355 		}
356 	}
357 
358 	return NULL;
359 }
360 
361 /**
362  * of_platform_bus_create() - Create a device for a node and its children.
363  * @bus: device node of the bus to instantiate
364  * @matches: match table for bus nodes
365  * @lookup: auxdata table for matching id and platform_data with device nodes
366  * @parent: parent for new device, or NULL for top level.
367  * @strict: require compatible property
368  *
369  * Creates a platform_device for the provided device_node, and optionally
370  * recursively create devices for all the child nodes.
371  */
372 static int of_platform_bus_create(struct device_node *bus,
373 				  const struct of_device_id *matches,
374 				  const struct of_dev_auxdata *lookup,
375 				  struct device *parent, bool strict)
376 {
377 	const struct of_dev_auxdata *auxdata;
378 	struct device_node *child;
379 	struct platform_device *dev;
380 	const char *bus_id = NULL;
381 	void *platform_data = NULL;
382 	int rc = 0;
383 
384 	/* Make sure it has a compatible property */
385 	if (strict && (!of_get_property(bus, "compatible", NULL))) {
386 		pr_debug("%s() - skipping %pOF, no compatible prop\n",
387 			 __func__, bus);
388 		return 0;
389 	}
390 
391 	/* Skip nodes for which we don't want to create devices */
392 	if (unlikely(of_match_node(of_skipped_node_table, bus))) {
393 		pr_debug("%s() - skipping %pOF node\n", __func__, bus);
394 		return 0;
395 	}
396 
397 	if (of_node_check_flag(bus, OF_POPULATED_BUS)) {
398 		pr_debug("%s() - skipping %pOF, already populated\n",
399 			__func__, bus);
400 		return 0;
401 	}
402 
403 	auxdata = of_dev_lookup(lookup, bus);
404 	if (auxdata) {
405 		bus_id = auxdata->name;
406 		platform_data = auxdata->platform_data;
407 	}
408 
409 	if (of_device_is_compatible(bus, "arm,primecell")) {
410 		/*
411 		 * Don't return an error here to keep compatibility with older
412 		 * device tree files.
413 		 */
414 		of_amba_device_create(bus, bus_id, platform_data, parent);
415 		return 0;
416 	}
417 
418 	dev = of_platform_device_create_pdata(bus, bus_id, platform_data, parent);
419 	if (!dev || !of_match_node(matches, bus))
420 		return 0;
421 
422 	for_each_child_of_node(bus, child) {
423 		pr_debug("   create child: %pOF\n", child);
424 		rc = of_platform_bus_create(child, matches, lookup, &dev->dev, strict);
425 		if (rc) {
426 			of_node_put(child);
427 			break;
428 		}
429 	}
430 	of_node_set_flag(bus, OF_POPULATED_BUS);
431 	return rc;
432 }
433 
434 /**
435  * of_platform_bus_probe() - Probe the device-tree for platform buses
436  * @root: parent of the first level to probe or NULL for the root of the tree
437  * @matches: match table for bus nodes
438  * @parent: parent to hook devices from, NULL for toplevel
439  *
440  * Note that children of the provided root are not instantiated as devices
441  * unless the specified root itself matches the bus list and is not NULL.
442  */
443 int of_platform_bus_probe(struct device_node *root,
444 			  const struct of_device_id *matches,
445 			  struct device *parent)
446 {
447 	struct device_node *child;
448 	int rc = 0;
449 
450 	root = root ? of_node_get(root) : of_find_node_by_path("/");
451 	if (!root)
452 		return -EINVAL;
453 
454 	pr_debug("%s()\n", __func__);
455 	pr_debug(" starting at: %pOF\n", root);
456 
457 	/* Do a self check of bus type, if there's a match, create children */
458 	if (of_match_node(matches, root)) {
459 		rc = of_platform_bus_create(root, matches, NULL, parent, false);
460 	} else for_each_child_of_node(root, child) {
461 		if (!of_match_node(matches, child))
462 			continue;
463 		rc = of_platform_bus_create(child, matches, NULL, parent, false);
464 		if (rc) {
465 			of_node_put(child);
466 			break;
467 		}
468 	}
469 
470 	of_node_put(root);
471 	return rc;
472 }
473 EXPORT_SYMBOL(of_platform_bus_probe);
474 
475 /**
476  * of_platform_populate() - Populate platform_devices from device tree data
477  * @root: parent of the first level to probe or NULL for the root of the tree
478  * @matches: match table, NULL to use the default
479  * @lookup: auxdata table for matching id and platform_data with device nodes
480  * @parent: parent to hook devices from, NULL for toplevel
481  *
482  * Similar to of_platform_bus_probe(), this function walks the device tree
483  * and creates devices from nodes.  It differs in that it follows the modern
484  * convention of requiring all device nodes to have a 'compatible' property,
485  * and it is suitable for creating devices which are children of the root
486  * node (of_platform_bus_probe will only create children of the root which
487  * are selected by the @matches argument).
488  *
489  * New board support should be using this function instead of
490  * of_platform_bus_probe().
491  *
492  * Return: 0 on success, < 0 on failure.
493  */
494 int of_platform_populate(struct device_node *root,
495 			const struct of_device_id *matches,
496 			const struct of_dev_auxdata *lookup,
497 			struct device *parent)
498 {
499 	struct device_node *child;
500 	int rc = 0;
501 
502 	root = root ? of_node_get(root) : of_find_node_by_path("/");
503 	if (!root)
504 		return -EINVAL;
505 
506 	pr_debug("%s()\n", __func__);
507 	pr_debug(" starting at: %pOF\n", root);
508 
509 	device_links_supplier_sync_state_pause();
510 	for_each_child_of_node(root, child) {
511 		rc = of_platform_bus_create(child, matches, lookup, parent, true);
512 		if (rc) {
513 			of_node_put(child);
514 			break;
515 		}
516 	}
517 	device_links_supplier_sync_state_resume();
518 
519 	of_node_set_flag(root, OF_POPULATED_BUS);
520 
521 	of_node_put(root);
522 	return rc;
523 }
524 EXPORT_SYMBOL_GPL(of_platform_populate);
525 
526 int of_platform_default_populate(struct device_node *root,
527 				 const struct of_dev_auxdata *lookup,
528 				 struct device *parent)
529 {
530 	return of_platform_populate(root, of_default_bus_match_table, lookup,
531 				    parent);
532 }
533 EXPORT_SYMBOL_GPL(of_platform_default_populate);
534 
535 static const struct of_device_id reserved_mem_matches[] = {
536 	{ .compatible = "phram" },
537 	{ .compatible = "qcom,rmtfs-mem" },
538 	{ .compatible = "qcom,cmd-db" },
539 	{ .compatible = "qcom,smem" },
540 	{ .compatible = "ramoops" },
541 	{ .compatible = "nvmem-rmem" },
542 	{ .compatible = "google,open-dice" },
543 	{}
544 };
545 
546 static int __init of_platform_default_populate_init(void)
547 {
548 	struct device_node *node;
549 
550 	device_links_supplier_sync_state_pause();
551 
552 	if (!of_have_populated_dt())
553 		return -ENODEV;
554 
555 	if (IS_ENABLED(CONFIG_PPC)) {
556 		struct device_node *boot_display = NULL;
557 		struct platform_device *dev;
558 		int display_number = 0;
559 		int ret;
560 
561 		/* Check if we have a MacOS display without a node spec */
562 		if (of_property_present(of_chosen, "linux,bootx-noscreen")) {
563 			/*
564 			 * The old code tried to work out which node was the MacOS
565 			 * display based on the address. I'm dropping that since the
566 			 * lack of a node spec only happens with old BootX versions
567 			 * (users can update) and with this code, they'll still get
568 			 * a display (just not the palette hacks).
569 			 */
570 			dev = platform_device_alloc("bootx-noscreen", 0);
571 			if (WARN_ON(!dev))
572 				return -ENOMEM;
573 			ret = platform_device_add(dev);
574 			if (WARN_ON(ret)) {
575 				platform_device_put(dev);
576 				return ret;
577 			}
578 		}
579 
580 		/*
581 		 * For OF framebuffers, first create the device for the boot display,
582 		 * then for the other framebuffers. Only fail for the boot display;
583 		 * ignore errors for the rest.
584 		 */
585 		for_each_node_by_type(node, "display") {
586 			if (!of_get_property(node, "linux,opened", NULL) ||
587 			    !of_get_property(node, "linux,boot-display", NULL))
588 				continue;
589 			dev = of_platform_device_create(node, "of-display", NULL);
590 			of_node_put(node);
591 			if (WARN_ON(!dev))
592 				return -ENOMEM;
593 			boot_display = node;
594 			display_number++;
595 			break;
596 		}
597 		for_each_node_by_type(node, "display") {
598 			char buf[14];
599 			const char *of_display_format = "of-display.%d";
600 
601 			if (!of_get_property(node, "linux,opened", NULL) || node == boot_display)
602 				continue;
603 			ret = snprintf(buf, sizeof(buf), of_display_format, display_number++);
604 			if (ret < sizeof(buf))
605 				of_platform_device_create(node, buf, NULL);
606 		}
607 
608 	} else {
609 		/*
610 		 * Handle certain compatibles explicitly, since we don't want to create
611 		 * platform_devices for every node in /reserved-memory with a
612 		 * "compatible",
613 		 */
614 		for_each_matching_node(node, reserved_mem_matches)
615 			of_platform_device_create(node, NULL, NULL);
616 
617 		node = of_find_node_by_path("/firmware");
618 		if (node) {
619 			of_platform_populate(node, NULL, NULL, NULL);
620 			of_node_put(node);
621 		}
622 
623 		node = of_get_compatible_child(of_chosen, "simple-framebuffer");
624 		of_platform_device_create(node, NULL, NULL);
625 		of_node_put(node);
626 
627 		/* Populate everything else. */
628 		of_platform_default_populate(NULL, NULL, NULL);
629 	}
630 
631 	return 0;
632 }
633 arch_initcall_sync(of_platform_default_populate_init);
634 
635 static int __init of_platform_sync_state_init(void)
636 {
637 	device_links_supplier_sync_state_resume();
638 	return 0;
639 }
640 late_initcall_sync(of_platform_sync_state_init);
641 
642 int of_platform_device_destroy(struct device *dev, void *data)
643 {
644 	/* Do not touch devices not populated from the device tree */
645 	if (!dev->of_node || !of_node_check_flag(dev->of_node, OF_POPULATED))
646 		return 0;
647 
648 	/* Recurse for any nodes that were treated as busses */
649 	if (of_node_check_flag(dev->of_node, OF_POPULATED_BUS))
650 		device_for_each_child(dev, NULL, of_platform_device_destroy);
651 
652 	of_node_clear_flag(dev->of_node, OF_POPULATED);
653 	of_node_clear_flag(dev->of_node, OF_POPULATED_BUS);
654 
655 	if (dev->bus == &platform_bus_type)
656 		platform_device_unregister(to_platform_device(dev));
657 #ifdef CONFIG_ARM_AMBA
658 	else if (dev->bus == &amba_bustype)
659 		amba_device_unregister(to_amba_device(dev));
660 #endif
661 
662 	return 0;
663 }
664 EXPORT_SYMBOL_GPL(of_platform_device_destroy);
665 
666 /**
667  * of_platform_depopulate() - Remove devices populated from device tree
668  * @parent: device which children will be removed
669  *
670  * Complementary to of_platform_populate(), this function removes children
671  * of the given device (and, recurrently, their children) that have been
672  * created from their respective device tree nodes (and only those,
673  * leaving others - eg. manually created - unharmed).
674  */
675 void of_platform_depopulate(struct device *parent)
676 {
677 	if (parent->of_node && of_node_check_flag(parent->of_node, OF_POPULATED_BUS)) {
678 		device_for_each_child_reverse(parent, NULL, of_platform_device_destroy);
679 		of_node_clear_flag(parent->of_node, OF_POPULATED_BUS);
680 	}
681 }
682 EXPORT_SYMBOL_GPL(of_platform_depopulate);
683 
684 static void devm_of_platform_populate_release(struct device *dev, void *res)
685 {
686 	of_platform_depopulate(*(struct device **)res);
687 }
688 
689 /**
690  * devm_of_platform_populate() - Populate platform_devices from device tree data
691  * @dev: device that requested to populate from device tree data
692  *
693  * Similar to of_platform_populate(), but will automatically call
694  * of_platform_depopulate() when the device is unbound from the bus.
695  *
696  * Return: 0 on success, < 0 on failure.
697  */
698 int devm_of_platform_populate(struct device *dev)
699 {
700 	struct device **ptr;
701 	int ret;
702 
703 	if (!dev)
704 		return -EINVAL;
705 
706 	ptr = devres_alloc(devm_of_platform_populate_release,
707 			   sizeof(*ptr), GFP_KERNEL);
708 	if (!ptr)
709 		return -ENOMEM;
710 
711 	ret = of_platform_populate(dev->of_node, NULL, NULL, dev);
712 	if (ret) {
713 		devres_free(ptr);
714 	} else {
715 		*ptr = dev;
716 		devres_add(dev, ptr);
717 	}
718 
719 	return ret;
720 }
721 EXPORT_SYMBOL_GPL(devm_of_platform_populate);
722 
723 static int devm_of_platform_match(struct device *dev, void *res, void *data)
724 {
725 	struct device **ptr = res;
726 
727 	if (!ptr) {
728 		WARN_ON(!ptr);
729 		return 0;
730 	}
731 
732 	return *ptr == data;
733 }
734 
735 /**
736  * devm_of_platform_depopulate() - Remove devices populated from device tree
737  * @dev: device that requested to depopulate from device tree data
738  *
739  * Complementary to devm_of_platform_populate(), this function removes children
740  * of the given device (and, recurrently, their children) that have been
741  * created from their respective device tree nodes (and only those,
742  * leaving others - eg. manually created - unharmed).
743  */
744 void devm_of_platform_depopulate(struct device *dev)
745 {
746 	int ret;
747 
748 	ret = devres_release(dev, devm_of_platform_populate_release,
749 			     devm_of_platform_match, dev);
750 
751 	WARN_ON(ret);
752 }
753 EXPORT_SYMBOL_GPL(devm_of_platform_depopulate);
754 
755 #ifdef CONFIG_OF_DYNAMIC
756 static int of_platform_notify(struct notifier_block *nb,
757 				unsigned long action, void *arg)
758 {
759 	struct of_reconfig_data *rd = arg;
760 	struct platform_device *pdev_parent, *pdev;
761 	bool children_left;
762 
763 	switch (of_reconfig_get_state_change(action, rd)) {
764 	case OF_RECONFIG_CHANGE_ADD:
765 		/* verify that the parent is a bus */
766 		if (!of_node_check_flag(rd->dn->parent, OF_POPULATED_BUS))
767 			return NOTIFY_OK;	/* not for us */
768 
769 		/* already populated? (driver using of_populate manually) */
770 		if (of_node_check_flag(rd->dn, OF_POPULATED))
771 			return NOTIFY_OK;
772 
773 		/*
774 		 * Clear the flag before adding the device so that fw_devlink
775 		 * doesn't skip adding consumers to this device.
776 		 */
777 		rd->dn->fwnode.flags &= ~FWNODE_FLAG_NOT_DEVICE;
778 		/* pdev_parent may be NULL when no bus platform device */
779 		pdev_parent = of_find_device_by_node(rd->dn->parent);
780 		pdev = of_platform_device_create(rd->dn, NULL,
781 				pdev_parent ? &pdev_parent->dev : NULL);
782 		platform_device_put(pdev_parent);
783 
784 		if (pdev == NULL) {
785 			pr_err("%s: failed to create for '%pOF'\n",
786 					__func__, rd->dn);
787 			/* of_platform_device_create tosses the error code */
788 			return notifier_from_errno(-EINVAL);
789 		}
790 		break;
791 
792 	case OF_RECONFIG_CHANGE_REMOVE:
793 
794 		/* already depopulated? */
795 		if (!of_node_check_flag(rd->dn, OF_POPULATED))
796 			return NOTIFY_OK;
797 
798 		/* find our device by node */
799 		pdev = of_find_device_by_node(rd->dn);
800 		if (pdev == NULL)
801 			return NOTIFY_OK;	/* no? not meant for us */
802 
803 		/* unregister takes one ref away */
804 		of_platform_device_destroy(&pdev->dev, &children_left);
805 
806 		/* and put the reference of the find */
807 		platform_device_put(pdev);
808 		break;
809 	}
810 
811 	return NOTIFY_OK;
812 }
813 
814 static struct notifier_block platform_of_notifier = {
815 	.notifier_call = of_platform_notify,
816 };
817 
818 void of_platform_register_reconfig_notifier(void)
819 {
820 	WARN_ON(of_reconfig_notifier_register(&platform_of_notifier));
821 }
822 #endif /* CONFIG_OF_DYNAMIC */
823 
824 #endif /* CONFIG_OF_ADDRESS */
825