xref: /openbmc/u-boot/drivers/core/uclass.c (revision d905726f)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Copyright (c) 2013 Google, Inc
4  *
5  * (C) Copyright 2012
6  * Pavel Herrmann <morpheus.ibis@gmail.com>
7  */
8 
9 #include <common.h>
10 #include <dm.h>
11 #include <errno.h>
12 #include <malloc.h>
13 #include <dm/device.h>
14 #include <dm/device-internal.h>
15 #include <dm/lists.h>
16 #include <dm/uclass.h>
17 #include <dm/uclass-internal.h>
18 #include <dm/util.h>
19 
20 DECLARE_GLOBAL_DATA_PTR;
21 
uclass_find(enum uclass_id key)22 struct uclass *uclass_find(enum uclass_id key)
23 {
24 	struct uclass *uc;
25 
26 	if (!gd->dm_root)
27 		return NULL;
28 	/*
29 	 * TODO(sjg@chromium.org): Optimise this, perhaps moving the found
30 	 * node to the start of the list, or creating a linear array mapping
31 	 * id to node.
32 	 */
33 	list_for_each_entry(uc, &gd->uclass_root, sibling_node) {
34 		if (uc->uc_drv->id == key)
35 			return uc;
36 	}
37 
38 	return NULL;
39 }
40 
41 /**
42  * uclass_add() - Create new uclass in list
43  * @id: Id number to create
44  * @ucp: Returns pointer to uclass, or NULL on error
45  * @return 0 on success, -ve on error
46  *
47  * The new uclass is added to the list. There must be only one uclass for
48  * each id.
49  */
uclass_add(enum uclass_id id,struct uclass ** ucp)50 static int uclass_add(enum uclass_id id, struct uclass **ucp)
51 {
52 	struct uclass_driver *uc_drv;
53 	struct uclass *uc;
54 	int ret;
55 
56 	*ucp = NULL;
57 	uc_drv = lists_uclass_lookup(id);
58 	if (!uc_drv) {
59 		debug("Cannot find uclass for id %d: please add the UCLASS_DRIVER() declaration for this UCLASS_... id\n",
60 		      id);
61 		/*
62 		 * Use a strange error to make this case easier to find. When
63 		 * a uclass is not available it can prevent driver model from
64 		 * starting up and this failure is otherwise hard to debug.
65 		 */
66 		return -EPFNOSUPPORT;
67 	}
68 	uc = calloc(1, sizeof(*uc));
69 	if (!uc)
70 		return -ENOMEM;
71 	if (uc_drv->priv_auto_alloc_size) {
72 		uc->priv = calloc(1, uc_drv->priv_auto_alloc_size);
73 		if (!uc->priv) {
74 			ret = -ENOMEM;
75 			goto fail_mem;
76 		}
77 	}
78 	uc->uc_drv = uc_drv;
79 	INIT_LIST_HEAD(&uc->sibling_node);
80 	INIT_LIST_HEAD(&uc->dev_head);
81 	list_add(&uc->sibling_node, &DM_UCLASS_ROOT_NON_CONST);
82 
83 	if (uc_drv->init) {
84 		ret = uc_drv->init(uc);
85 		if (ret)
86 			goto fail;
87 	}
88 
89 	*ucp = uc;
90 
91 	return 0;
92 fail:
93 	if (uc_drv->priv_auto_alloc_size) {
94 		free(uc->priv);
95 		uc->priv = NULL;
96 	}
97 	list_del(&uc->sibling_node);
98 fail_mem:
99 	free(uc);
100 
101 	return ret;
102 }
103 
uclass_destroy(struct uclass * uc)104 int uclass_destroy(struct uclass *uc)
105 {
106 	struct uclass_driver *uc_drv;
107 	struct udevice *dev;
108 	int ret;
109 
110 	/*
111 	 * We cannot use list_for_each_entry_safe() here. If a device in this
112 	 * uclass has a child device also in this uclass, it will be also be
113 	 * unbound (by the recursion in the call to device_unbind() below).
114 	 * We can loop until the list is empty.
115 	 */
116 	while (!list_empty(&uc->dev_head)) {
117 		dev = list_first_entry(&uc->dev_head, struct udevice,
118 				       uclass_node);
119 		ret = device_remove(dev, DM_REMOVE_NORMAL);
120 		if (ret)
121 			return ret;
122 		ret = device_unbind(dev);
123 		if (ret)
124 			return ret;
125 	}
126 
127 	uc_drv = uc->uc_drv;
128 	if (uc_drv->destroy)
129 		uc_drv->destroy(uc);
130 	list_del(&uc->sibling_node);
131 	if (uc_drv->priv_auto_alloc_size)
132 		free(uc->priv);
133 	free(uc);
134 
135 	return 0;
136 }
137 
uclass_get(enum uclass_id id,struct uclass ** ucp)138 int uclass_get(enum uclass_id id, struct uclass **ucp)
139 {
140 	struct uclass *uc;
141 
142 	*ucp = NULL;
143 	uc = uclass_find(id);
144 	if (!uc)
145 		return uclass_add(id, ucp);
146 	*ucp = uc;
147 
148 	return 0;
149 }
150 
uclass_get_name(enum uclass_id id)151 const char *uclass_get_name(enum uclass_id id)
152 {
153 	struct uclass *uc;
154 
155 	if (uclass_get(id, &uc))
156 		return NULL;
157 	return uc->uc_drv->name;
158 }
159 
uclass_get_by_name(const char * name)160 enum uclass_id uclass_get_by_name(const char *name)
161 {
162 	int i;
163 
164 	for (i = 0; i < UCLASS_COUNT; i++) {
165 		struct uclass_driver *uc_drv = lists_uclass_lookup(i);
166 
167 		if (uc_drv && !strcmp(uc_drv->name, name))
168 			return i;
169 	}
170 
171 	return UCLASS_INVALID;
172 }
173 
dev_get_uclass_index(struct udevice * dev,struct uclass ** ucp)174 int dev_get_uclass_index(struct udevice *dev, struct uclass **ucp)
175 {
176 	struct udevice *iter;
177 	struct uclass *uc = dev->uclass;
178 	int i = 0;
179 
180 	if (list_empty(&uc->dev_head))
181 		return -ENODEV;
182 
183 	uclass_foreach_dev(iter, uc) {
184 		if (iter == dev) {
185 			if (ucp)
186 				*ucp = uc;
187 			return i;
188 		}
189 		i++;
190 	}
191 
192 	return -ENODEV;
193 }
194 
uclass_find_device(enum uclass_id id,int index,struct udevice ** devp)195 int uclass_find_device(enum uclass_id id, int index, struct udevice **devp)
196 {
197 	struct uclass *uc;
198 	struct udevice *dev;
199 	int ret;
200 
201 	*devp = NULL;
202 	ret = uclass_get(id, &uc);
203 	if (ret)
204 		return ret;
205 	if (list_empty(&uc->dev_head))
206 		return -ENODEV;
207 
208 	uclass_foreach_dev(dev, uc) {
209 		if (!index--) {
210 			*devp = dev;
211 			return 0;
212 		}
213 	}
214 
215 	return -ENODEV;
216 }
217 
uclass_find_first_device(enum uclass_id id,struct udevice ** devp)218 int uclass_find_first_device(enum uclass_id id, struct udevice **devp)
219 {
220 	struct uclass *uc;
221 	int ret;
222 
223 	*devp = NULL;
224 	ret = uclass_get(id, &uc);
225 	if (ret)
226 		return ret;
227 	if (list_empty(&uc->dev_head))
228 		return -ENODEV;
229 
230 	*devp = list_first_entry(&uc->dev_head, struct udevice, uclass_node);
231 
232 	return 0;
233 }
234 
uclass_find_next_device(struct udevice ** devp)235 int uclass_find_next_device(struct udevice **devp)
236 {
237 	struct udevice *dev = *devp;
238 
239 	*devp = NULL;
240 	if (list_is_last(&dev->uclass_node, &dev->uclass->dev_head))
241 		return 0;
242 
243 	*devp = list_entry(dev->uclass_node.next, struct udevice, uclass_node);
244 
245 	return 0;
246 }
247 
uclass_find_device_by_name(enum uclass_id id,const char * name,struct udevice ** devp)248 int uclass_find_device_by_name(enum uclass_id id, const char *name,
249 			       struct udevice **devp)
250 {
251 	struct uclass *uc;
252 	struct udevice *dev;
253 	int ret;
254 
255 	*devp = NULL;
256 	if (!name)
257 		return -EINVAL;
258 	ret = uclass_get(id, &uc);
259 	if (ret)
260 		return ret;
261 
262 	uclass_foreach_dev(dev, uc) {
263 		if (!strncmp(dev->name, name, strlen(name))) {
264 			*devp = dev;
265 			return 0;
266 		}
267 	}
268 
269 	return -ENODEV;
270 }
271 
272 #if !CONFIG_IS_ENABLED(OF_CONTROL) || CONFIG_IS_ENABLED(OF_PLATDATA)
uclass_find_next_free_req_seq(enum uclass_id id)273 int uclass_find_next_free_req_seq(enum uclass_id id)
274 {
275 	struct uclass *uc;
276 	struct udevice *dev;
277 	int ret;
278 	int max = -1;
279 
280 	ret = uclass_get(id, &uc);
281 	if (ret)
282 		return ret;
283 
284 	list_for_each_entry(dev, &uc->dev_head, uclass_node) {
285 		if ((dev->req_seq != -1) && (dev->req_seq > max))
286 			max = dev->req_seq;
287 	}
288 
289 	if (max == -1)
290 		return 0;
291 
292 	return max + 1;
293 }
294 #endif
295 
uclass_find_device_by_seq(enum uclass_id id,int seq_or_req_seq,bool find_req_seq,struct udevice ** devp)296 int uclass_find_device_by_seq(enum uclass_id id, int seq_or_req_seq,
297 			      bool find_req_seq, struct udevice **devp)
298 {
299 	struct uclass *uc;
300 	struct udevice *dev;
301 	int ret;
302 
303 	*devp = NULL;
304 	debug("%s: %d %d\n", __func__, find_req_seq, seq_or_req_seq);
305 	if (seq_or_req_seq == -1)
306 		return -ENODEV;
307 	ret = uclass_get(id, &uc);
308 	if (ret)
309 		return ret;
310 
311 	uclass_foreach_dev(dev, uc) {
312 		debug("   - %d %d '%s'\n", dev->req_seq, dev->seq, dev->name);
313 		if ((find_req_seq ? dev->req_seq : dev->seq) ==
314 				seq_or_req_seq) {
315 			*devp = dev;
316 			debug("   - found\n");
317 			return 0;
318 		}
319 	}
320 	debug("   - not found\n");
321 
322 	return -ENODEV;
323 }
324 
uclass_find_device_by_of_offset(enum uclass_id id,int node,struct udevice ** devp)325 int uclass_find_device_by_of_offset(enum uclass_id id, int node,
326 				    struct udevice **devp)
327 {
328 	struct uclass *uc;
329 	struct udevice *dev;
330 	int ret;
331 
332 	*devp = NULL;
333 	if (node < 0)
334 		return -ENODEV;
335 	ret = uclass_get(id, &uc);
336 	if (ret)
337 		return ret;
338 
339 	uclass_foreach_dev(dev, uc) {
340 		if (dev_of_offset(dev) == node) {
341 			*devp = dev;
342 			return 0;
343 		}
344 	}
345 
346 	return -ENODEV;
347 }
348 
uclass_find_device_by_ofnode(enum uclass_id id,ofnode node,struct udevice ** devp)349 int uclass_find_device_by_ofnode(enum uclass_id id, ofnode node,
350 				 struct udevice **devp)
351 {
352 	struct uclass *uc;
353 	struct udevice *dev;
354 	int ret;
355 
356 	log(LOGC_DM, LOGL_DEBUG, "Looking for %s\n", ofnode_get_name(node));
357 	*devp = NULL;
358 	if (!ofnode_valid(node))
359 		return -ENODEV;
360 	ret = uclass_get(id, &uc);
361 	if (ret)
362 		return ret;
363 
364 	uclass_foreach_dev(dev, uc) {
365 		log(LOGC_DM, LOGL_DEBUG_CONTENT, "      - checking %s\n",
366 		    dev->name);
367 		if (ofnode_equal(dev_ofnode(dev), node)) {
368 			*devp = dev;
369 			goto done;
370 		}
371 	}
372 	ret = -ENODEV;
373 
374 done:
375 	log(LOGC_DM, LOGL_DEBUG, "   - result for %s: %s (ret=%d)\n",
376 	    ofnode_get_name(node), *devp ? (*devp)->name : "(none)", ret);
377 	return ret;
378 }
379 
380 #if CONFIG_IS_ENABLED(OF_CONTROL)
uclass_find_device_by_phandle(enum uclass_id id,struct udevice * parent,const char * name,struct udevice ** devp)381 int uclass_find_device_by_phandle(enum uclass_id id, struct udevice *parent,
382 				  const char *name, struct udevice **devp)
383 {
384 	struct udevice *dev;
385 	struct uclass *uc;
386 	int find_phandle;
387 	int ret;
388 
389 	*devp = NULL;
390 	find_phandle = dev_read_u32_default(parent, name, -1);
391 	if (find_phandle <= 0)
392 		return -ENOENT;
393 	ret = uclass_get(id, &uc);
394 	if (ret)
395 		return ret;
396 
397 	uclass_foreach_dev(dev, uc) {
398 		uint phandle;
399 
400 		phandle = dev_read_phandle(dev);
401 
402 		if (phandle == find_phandle) {
403 			*devp = dev;
404 			return 0;
405 		}
406 	}
407 
408 	return -ENODEV;
409 }
410 #endif
411 
uclass_get_device_by_driver(enum uclass_id id,const struct driver * find_drv,struct udevice ** devp)412 int uclass_get_device_by_driver(enum uclass_id id,
413 				const struct driver *find_drv,
414 				struct udevice **devp)
415 {
416 	struct udevice *dev;
417 	struct uclass *uc;
418 	int ret;
419 
420 	ret = uclass_get(id, &uc);
421 	if (ret)
422 		return ret;
423 
424 	uclass_foreach_dev(dev, uc) {
425 		if (dev->driver == find_drv)
426 			return uclass_get_device_tail(dev, 0, devp);
427 	}
428 
429 	return -ENODEV;
430 }
431 
uclass_get_device_tail(struct udevice * dev,int ret,struct udevice ** devp)432 int uclass_get_device_tail(struct udevice *dev, int ret, struct udevice **devp)
433 {
434 	if (ret)
435 		return ret;
436 
437 	assert(dev);
438 	ret = device_probe(dev);
439 	if (ret)
440 		return ret;
441 
442 	*devp = dev;
443 
444 	return 0;
445 }
446 
uclass_get_device(enum uclass_id id,int index,struct udevice ** devp)447 int uclass_get_device(enum uclass_id id, int index, struct udevice **devp)
448 {
449 	struct udevice *dev;
450 	int ret;
451 
452 	*devp = NULL;
453 	ret = uclass_find_device(id, index, &dev);
454 	return uclass_get_device_tail(dev, ret, devp);
455 }
456 
uclass_get_device_by_name(enum uclass_id id,const char * name,struct udevice ** devp)457 int uclass_get_device_by_name(enum uclass_id id, const char *name,
458 			      struct udevice **devp)
459 {
460 	struct udevice *dev;
461 	int ret;
462 
463 	*devp = NULL;
464 	ret = uclass_find_device_by_name(id, name, &dev);
465 	return uclass_get_device_tail(dev, ret, devp);
466 }
467 
uclass_get_device_by_seq(enum uclass_id id,int seq,struct udevice ** devp)468 int uclass_get_device_by_seq(enum uclass_id id, int seq, struct udevice **devp)
469 {
470 	struct udevice *dev;
471 	int ret;
472 
473 	*devp = NULL;
474 	ret = uclass_find_device_by_seq(id, seq, false, &dev);
475 	if (ret == -ENODEV) {
476 		/*
477 		 * We didn't find it in probed devices. See if there is one
478 		 * that will request this seq if probed.
479 		 */
480 		ret = uclass_find_device_by_seq(id, seq, true, &dev);
481 	}
482 	return uclass_get_device_tail(dev, ret, devp);
483 }
484 
uclass_get_device_by_of_offset(enum uclass_id id,int node,struct udevice ** devp)485 int uclass_get_device_by_of_offset(enum uclass_id id, int node,
486 				   struct udevice **devp)
487 {
488 	struct udevice *dev;
489 	int ret;
490 
491 	*devp = NULL;
492 	ret = uclass_find_device_by_of_offset(id, node, &dev);
493 	return uclass_get_device_tail(dev, ret, devp);
494 }
495 
uclass_get_device_by_ofnode(enum uclass_id id,ofnode node,struct udevice ** devp)496 int uclass_get_device_by_ofnode(enum uclass_id id, ofnode node,
497 				struct udevice **devp)
498 {
499 	struct udevice *dev;
500 	int ret;
501 
502 	log(LOGC_DM, LOGL_DEBUG, "Looking for %s\n", ofnode_get_name(node));
503 	*devp = NULL;
504 	ret = uclass_find_device_by_ofnode(id, node, &dev);
505 	log(LOGC_DM, LOGL_DEBUG, "   - result for %s: %s (ret=%d)\n",
506 	    ofnode_get_name(node), dev ? dev->name : "(none)", ret);
507 
508 	return uclass_get_device_tail(dev, ret, devp);
509 }
510 
511 #if CONFIG_IS_ENABLED(OF_CONTROL)
uclass_get_device_by_phandle_id(enum uclass_id id,uint phandle_id,struct udevice ** devp)512 int uclass_get_device_by_phandle_id(enum uclass_id id, uint phandle_id,
513 				    struct udevice **devp)
514 {
515 	struct udevice *dev;
516 	struct uclass *uc;
517 	int ret;
518 
519 	*devp = NULL;
520 	ret = uclass_get(id, &uc);
521 	if (ret)
522 		return ret;
523 
524 	uclass_foreach_dev(dev, uc) {
525 		uint phandle;
526 
527 		phandle = dev_read_phandle(dev);
528 
529 		if (phandle == phandle_id) {
530 			*devp = dev;
531 			return uclass_get_device_tail(dev, ret, devp);
532 		}
533 	}
534 
535 	return -ENODEV;
536 }
537 
uclass_get_device_by_phandle(enum uclass_id id,struct udevice * parent,const char * name,struct udevice ** devp)538 int uclass_get_device_by_phandle(enum uclass_id id, struct udevice *parent,
539 				 const char *name, struct udevice **devp)
540 {
541 	struct udevice *dev;
542 	int ret;
543 
544 	*devp = NULL;
545 	ret = uclass_find_device_by_phandle(id, parent, name, &dev);
546 	return uclass_get_device_tail(dev, ret, devp);
547 }
548 #endif
549 
uclass_first_device(enum uclass_id id,struct udevice ** devp)550 int uclass_first_device(enum uclass_id id, struct udevice **devp)
551 {
552 	struct udevice *dev;
553 	int ret;
554 
555 	*devp = NULL;
556 	ret = uclass_find_first_device(id, &dev);
557 	if (!dev)
558 		return 0;
559 	return uclass_get_device_tail(dev, ret, devp);
560 }
561 
uclass_first_device_err(enum uclass_id id,struct udevice ** devp)562 int uclass_first_device_err(enum uclass_id id, struct udevice **devp)
563 {
564 	int ret;
565 
566 	ret = uclass_first_device(id, devp);
567 	if (ret)
568 		return ret;
569 	else if (!*devp)
570 		return -ENODEV;
571 
572 	return 0;
573 }
574 
uclass_next_device(struct udevice ** devp)575 int uclass_next_device(struct udevice **devp)
576 {
577 	struct udevice *dev = *devp;
578 	int ret;
579 
580 	*devp = NULL;
581 	ret = uclass_find_next_device(&dev);
582 	if (!dev)
583 		return 0;
584 	return uclass_get_device_tail(dev, ret, devp);
585 }
586 
uclass_next_device_err(struct udevice ** devp)587 int uclass_next_device_err(struct udevice **devp)
588 {
589 	int ret;
590 
591 	ret = uclass_next_device(devp);
592 	if (ret)
593 		return ret;
594 	else if (!*devp)
595 		return -ENODEV;
596 
597 	return 0;
598 }
599 
uclass_first_device_check(enum uclass_id id,struct udevice ** devp)600 int uclass_first_device_check(enum uclass_id id, struct udevice **devp)
601 {
602 	int ret;
603 
604 	*devp = NULL;
605 	ret = uclass_find_first_device(id, devp);
606 	if (ret)
607 		return ret;
608 	if (!*devp)
609 		return 0;
610 
611 	return device_probe(*devp);
612 }
613 
uclass_next_device_check(struct udevice ** devp)614 int uclass_next_device_check(struct udevice **devp)
615 {
616 	int ret;
617 
618 	ret = uclass_find_next_device(devp);
619 	if (ret)
620 		return ret;
621 	if (!*devp)
622 		return 0;
623 
624 	return device_probe(*devp);
625 }
626 
uclass_bind_device(struct udevice * dev)627 int uclass_bind_device(struct udevice *dev)
628 {
629 	struct uclass *uc;
630 	int ret;
631 
632 	uc = dev->uclass;
633 	list_add_tail(&dev->uclass_node, &uc->dev_head);
634 
635 	if (dev->parent) {
636 		struct uclass_driver *uc_drv = dev->parent->uclass->uc_drv;
637 
638 		if (uc_drv->child_post_bind) {
639 			ret = uc_drv->child_post_bind(dev);
640 			if (ret)
641 				goto err;
642 		}
643 	}
644 
645 	return 0;
646 err:
647 	/* There is no need to undo the parent's post_bind call */
648 	list_del(&dev->uclass_node);
649 
650 	return ret;
651 }
652 
653 #if CONFIG_IS_ENABLED(DM_DEVICE_REMOVE)
uclass_unbind_device(struct udevice * dev)654 int uclass_unbind_device(struct udevice *dev)
655 {
656 	struct uclass *uc;
657 	int ret;
658 
659 	uc = dev->uclass;
660 	if (uc->uc_drv->pre_unbind) {
661 		ret = uc->uc_drv->pre_unbind(dev);
662 		if (ret)
663 			return ret;
664 	}
665 
666 	list_del(&dev->uclass_node);
667 	return 0;
668 }
669 #endif
670 
uclass_resolve_seq(struct udevice * dev)671 int uclass_resolve_seq(struct udevice *dev)
672 {
673 	struct udevice *dup;
674 	int seq;
675 	int ret;
676 
677 	assert(dev->seq == -1);
678 	ret = uclass_find_device_by_seq(dev->uclass->uc_drv->id, dev->req_seq,
679 					false, &dup);
680 	if (!ret) {
681 		dm_warn("Device '%s': seq %d is in use by '%s'\n",
682 			dev->name, dev->req_seq, dup->name);
683 	} else if (ret == -ENODEV) {
684 		/* Our requested sequence number is available */
685 		if (dev->req_seq != -1)
686 			return dev->req_seq;
687 	} else {
688 		return ret;
689 	}
690 
691 	for (seq = 0; seq < DM_MAX_SEQ; seq++) {
692 		ret = uclass_find_device_by_seq(dev->uclass->uc_drv->id, seq,
693 						false, &dup);
694 		if (ret == -ENODEV)
695 			break;
696 		if (ret)
697 			return ret;
698 	}
699 	return seq;
700 }
701 
uclass_pre_probe_device(struct udevice * dev)702 int uclass_pre_probe_device(struct udevice *dev)
703 {
704 	struct uclass_driver *uc_drv;
705 	int ret;
706 
707 	uc_drv = dev->uclass->uc_drv;
708 	if (uc_drv->pre_probe) {
709 		ret = uc_drv->pre_probe(dev);
710 		if (ret)
711 			return ret;
712 	}
713 
714 	if (!dev->parent)
715 		return 0;
716 	uc_drv = dev->parent->uclass->uc_drv;
717 	if (uc_drv->child_pre_probe)
718 		return uc_drv->child_pre_probe(dev);
719 
720 	return 0;
721 }
722 
uclass_post_probe_device(struct udevice * dev)723 int uclass_post_probe_device(struct udevice *dev)
724 {
725 	struct uclass_driver *uc_drv;
726 	int ret;
727 
728 	if (dev->parent) {
729 		uc_drv = dev->parent->uclass->uc_drv;
730 		if (uc_drv->child_post_probe) {
731 			ret = uc_drv->child_post_probe(dev);
732 			if (ret)
733 				return ret;
734 		}
735 	}
736 
737 	uc_drv = dev->uclass->uc_drv;
738 	if (uc_drv->post_probe)
739 		return uc_drv->post_probe(dev);
740 
741 	return 0;
742 }
743 
744 #if CONFIG_IS_ENABLED(DM_DEVICE_REMOVE)
uclass_pre_remove_device(struct udevice * dev)745 int uclass_pre_remove_device(struct udevice *dev)
746 {
747 	struct uclass *uc;
748 	int ret;
749 
750 	uc = dev->uclass;
751 	if (uc->uc_drv->pre_remove) {
752 		ret = uc->uc_drv->pre_remove(dev);
753 		if (ret)
754 			return ret;
755 	}
756 
757 	return 0;
758 }
759 #endif
760 
761 UCLASS_DRIVER(nop) = {
762 	.id		= UCLASS_NOP,
763 	.name		= "nop",
764 };
765