Line data Source code
1 : // SPDX-License-Identifier: GPL-2.0
2 : /*
3 : * Componentized device handling.
4 : *
5 : * This is work in progress. We gather up the component devices into a list,
6 : * and bind them when instructed. At the moment, we're specific to the DRM
7 : * subsystem, and only handles one master device, but this doesn't have to be
8 : * the case.
9 : */
10 : #include <linux/component.h>
11 : #include <linux/device.h>
12 : #include <linux/kref.h>
13 : #include <linux/list.h>
14 : #include <linux/mutex.h>
15 : #include <linux/slab.h>
16 : #include <linux/debugfs.h>
17 :
18 : /**
19 : * DOC: overview
20 : *
21 : * The component helper allows drivers to collect a pile of sub-devices,
22 : * including their bound drivers, into an aggregate driver. Various subsystems
23 : * already provide functions to get hold of such components, e.g.
24 : * of_clk_get_by_name(). The component helper can be used when such a
25 : * subsystem-specific way to find a device is not available: The component
26 : * helper fills the niche of aggregate drivers for specific hardware, where
27 : * further standardization into a subsystem would not be practical. The common
28 : * example is when a logical device (e.g. a DRM display driver) is spread around
29 : * the SoC on various components (scanout engines, blending blocks, transcoders
30 : * for various outputs and so on).
31 : *
32 : * The component helper also doesn't solve runtime dependencies, e.g. for system
33 : * suspend and resume operations. See also :ref:`device links<device_link>`.
34 : *
35 : * Components are registered using component_add() and unregistered with
36 : * component_del(), usually from the driver's probe and disconnect functions.
37 : *
38 : * Aggregate drivers first assemble a component match list of what they need
39 : * using component_match_add(). This is then registered as an aggregate driver
40 : * using component_master_add_with_match(), and unregistered using
41 : * component_master_del().
42 : */
43 :
44 : struct component;
45 :
46 : struct component_match_array {
47 : void *data;
48 : int (*compare)(struct device *, void *);
49 : int (*compare_typed)(struct device *, int, void *);
50 : void (*release)(struct device *, void *);
51 : struct component *component;
52 : bool duplicate;
53 : };
54 :
55 : struct component_match {
56 : size_t alloc;
57 : size_t num;
58 : struct component_match_array *compare;
59 : };
60 :
61 : struct master {
62 : struct list_head node;
63 : bool bound;
64 :
65 : const struct component_master_ops *ops;
66 : struct device *dev;
67 : struct component_match *match;
68 : struct dentry *dentry;
69 : };
70 :
71 : struct component {
72 : struct list_head node;
73 : struct master *master;
74 : bool bound;
75 :
76 : const struct component_ops *ops;
77 : int subcomponent;
78 : struct device *dev;
79 : };
80 :
81 : static DEFINE_MUTEX(component_mutex);
82 : static LIST_HEAD(component_list);
83 : static LIST_HEAD(masters);
84 :
85 : #ifdef CONFIG_DEBUG_FS
86 :
87 : static struct dentry *component_debugfs_dir;
88 :
89 0 : static int component_devices_show(struct seq_file *s, void *data)
90 : {
91 0 : struct master *m = s->private;
92 0 : struct component_match *match = m->match;
93 0 : size_t i;
94 :
95 0 : mutex_lock(&component_mutex);
96 0 : seq_printf(s, "%-40s %20s\n", "master name", "status");
97 0 : seq_puts(s, "-------------------------------------------------------------\n");
98 0 : seq_printf(s, "%-40s %20s\n\n",
99 0 : dev_name(m->dev), m->bound ? "bound" : "not bound");
100 :
101 0 : seq_printf(s, "%-40s %20s\n", "device name", "status");
102 0 : seq_puts(s, "-------------------------------------------------------------\n");
103 0 : for (i = 0; i < match->num; i++) {
104 0 : struct component *component = match->compare[i].component;
105 :
106 0 : seq_printf(s, "%-40s %20s\n",
107 0 : component ? dev_name(component->dev) : "(unknown)",
108 0 : component ? (component->bound ? "bound" : "not bound") : "not registered");
109 : }
110 0 : mutex_unlock(&component_mutex);
111 :
112 0 : return 0;
113 : }
114 :
115 0 : DEFINE_SHOW_ATTRIBUTE(component_devices);
116 :
117 1 : static int __init component_debug_init(void)
118 : {
119 1 : component_debugfs_dir = debugfs_create_dir("device_component", NULL);
120 :
121 1 : return 0;
122 : }
123 :
124 : core_initcall(component_debug_init);
125 :
126 0 : static void component_master_debugfs_add(struct master *m)
127 : {
128 0 : m->dentry = debugfs_create_file(dev_name(m->dev), 0444,
129 : component_debugfs_dir,
130 : m, &component_devices_fops);
131 0 : }
132 :
133 0 : static void component_master_debugfs_del(struct master *m)
134 : {
135 0 : debugfs_remove(m->dentry);
136 0 : m->dentry = NULL;
137 : }
138 :
139 : #else
140 :
141 : static void component_master_debugfs_add(struct master *m)
142 : { }
143 :
144 : static void component_master_debugfs_del(struct master *m)
145 : { }
146 :
147 : #endif
148 :
149 0 : static struct master *__master_find(struct device *dev,
150 : const struct component_master_ops *ops)
151 : {
152 0 : struct master *m;
153 :
154 0 : list_for_each_entry(m, &masters, node)
155 0 : if (m->dev == dev && (!ops || m->ops == ops))
156 0 : return m;
157 :
158 : return NULL;
159 : }
160 :
161 0 : static struct component *find_component(struct master *master,
162 : struct component_match_array *mc)
163 : {
164 0 : struct component *c;
165 :
166 0 : list_for_each_entry(c, &component_list, node) {
167 0 : if (c->master && c->master != master)
168 0 : continue;
169 :
170 0 : if (mc->compare && mc->compare(c->dev, mc->data))
171 0 : return c;
172 :
173 0 : if (mc->compare_typed &&
174 0 : mc->compare_typed(c->dev, c->subcomponent, mc->data))
175 0 : return c;
176 : }
177 :
178 : return NULL;
179 : }
180 :
181 0 : static int find_components(struct master *master)
182 : {
183 0 : struct component_match *match = master->match;
184 0 : size_t i;
185 0 : int ret = 0;
186 :
187 : /*
188 : * Scan the array of match functions and attach
189 : * any components which are found to this master.
190 : */
191 0 : for (i = 0; i < match->num; i++) {
192 0 : struct component_match_array *mc = &match->compare[i];
193 0 : struct component *c;
194 :
195 0 : dev_dbg(master->dev, "Looking for component %zu\n", i);
196 :
197 0 : if (match->compare[i].component)
198 0 : continue;
199 :
200 0 : c = find_component(master, mc);
201 0 : if (!c) {
202 : ret = -ENXIO;
203 : break;
204 : }
205 :
206 0 : dev_dbg(master->dev, "found component %s, duplicate %u\n", dev_name(c->dev), !!c->master);
207 :
208 : /* Attach this component to the master */
209 0 : match->compare[i].duplicate = !!c->master;
210 0 : match->compare[i].component = c;
211 0 : c->master = master;
212 : }
213 0 : return ret;
214 : }
215 :
216 : /* Detach component from associated master */
217 0 : static void remove_component(struct master *master, struct component *c)
218 : {
219 0 : size_t i;
220 :
221 : /* Detach the component from this master. */
222 0 : for (i = 0; i < master->match->num; i++)
223 0 : if (master->match->compare[i].component == c)
224 0 : master->match->compare[i].component = NULL;
225 0 : }
226 :
227 : /*
228 : * Try to bring up a master. If component is NULL, we're interested in
229 : * this master, otherwise it's a component which must be present to try
230 : * and bring up the master.
231 : *
232 : * Returns 1 for successful bringup, 0 if not ready, or -ve errno.
233 : */
234 0 : static int try_to_bring_up_master(struct master *master,
235 : struct component *component)
236 : {
237 0 : int ret;
238 :
239 0 : dev_dbg(master->dev, "trying to bring up master\n");
240 :
241 0 : if (find_components(master)) {
242 : dev_dbg(master->dev, "master has incomplete components\n");
243 : return 0;
244 : }
245 :
246 0 : if (component && component->master != master) {
247 : dev_dbg(master->dev, "master is not for this component (%s)\n",
248 : dev_name(component->dev));
249 : return 0;
250 : }
251 :
252 0 : if (!devres_open_group(master->dev, NULL, GFP_KERNEL))
253 : return -ENOMEM;
254 :
255 : /* Found all components */
256 0 : ret = master->ops->bind(master->dev);
257 0 : if (ret < 0) {
258 0 : devres_release_group(master->dev, NULL);
259 0 : if (ret != -EPROBE_DEFER)
260 0 : dev_info(master->dev, "master bind failed: %d\n", ret);
261 0 : return ret;
262 : }
263 :
264 0 : master->bound = true;
265 0 : return 1;
266 : }
267 :
268 0 : static int try_to_bring_up_masters(struct component *component)
269 : {
270 0 : struct master *m;
271 0 : int ret = 0;
272 :
273 0 : list_for_each_entry(m, &masters, node) {
274 0 : if (!m->bound) {
275 0 : ret = try_to_bring_up_master(m, component);
276 0 : if (ret != 0)
277 : break;
278 : }
279 : }
280 :
281 0 : return ret;
282 : }
283 :
284 0 : static void take_down_master(struct master *master)
285 : {
286 0 : if (master->bound) {
287 0 : master->ops->unbind(master->dev);
288 0 : devres_release_group(master->dev, NULL);
289 0 : master->bound = false;
290 : }
291 0 : }
292 :
293 0 : static void component_match_release(struct device *master,
294 : struct component_match *match)
295 : {
296 0 : unsigned int i;
297 :
298 0 : for (i = 0; i < match->num; i++) {
299 0 : struct component_match_array *mc = &match->compare[i];
300 :
301 0 : if (mc->release)
302 0 : mc->release(master, mc->data);
303 : }
304 :
305 0 : kfree(match->compare);
306 0 : }
307 :
308 0 : static void devm_component_match_release(struct device *dev, void *res)
309 : {
310 0 : component_match_release(dev, res);
311 0 : }
312 :
313 0 : static int component_match_realloc(struct device *dev,
314 : struct component_match *match, size_t num)
315 : {
316 0 : struct component_match_array *new;
317 :
318 0 : if (match->alloc == num)
319 : return 0;
320 :
321 0 : new = kmalloc_array(num, sizeof(*new), GFP_KERNEL);
322 0 : if (!new)
323 : return -ENOMEM;
324 :
325 0 : if (match->compare) {
326 0 : memcpy(new, match->compare, sizeof(*new) *
327 0 : min(match->num, num));
328 0 : kfree(match->compare);
329 : }
330 0 : match->compare = new;
331 0 : match->alloc = num;
332 :
333 0 : return 0;
334 : }
335 :
336 0 : static void __component_match_add(struct device *master,
337 : struct component_match **matchptr,
338 : void (*release)(struct device *, void *),
339 : int (*compare)(struct device *, void *),
340 : int (*compare_typed)(struct device *, int, void *),
341 : void *compare_data)
342 : {
343 0 : struct component_match *match = *matchptr;
344 :
345 0 : if (IS_ERR(match))
346 : return;
347 :
348 0 : if (!match) {
349 0 : match = devres_alloc(devm_component_match_release,
350 : sizeof(*match), GFP_KERNEL);
351 0 : if (!match) {
352 0 : *matchptr = ERR_PTR(-ENOMEM);
353 0 : return;
354 : }
355 :
356 0 : devres_add(master, match);
357 :
358 0 : *matchptr = match;
359 : }
360 :
361 0 : if (match->num == match->alloc) {
362 0 : size_t new_size = match->alloc + 16;
363 0 : int ret;
364 :
365 0 : ret = component_match_realloc(master, match, new_size);
366 0 : if (ret) {
367 0 : *matchptr = ERR_PTR(ret);
368 0 : return;
369 : }
370 : }
371 :
372 0 : match->compare[match->num].compare = compare;
373 0 : match->compare[match->num].compare_typed = compare_typed;
374 0 : match->compare[match->num].release = release;
375 0 : match->compare[match->num].data = compare_data;
376 0 : match->compare[match->num].component = NULL;
377 0 : match->num++;
378 : }
379 :
380 : /**
381 : * component_match_add_release - add a component match entry with release callback
382 : * @master: device with the aggregate driver
383 : * @matchptr: pointer to the list of component matches
384 : * @release: release function for @compare_data
385 : * @compare: compare function to match against all components
386 : * @compare_data: opaque pointer passed to the @compare function
387 : *
388 : * Adds a new component match to the list stored in @matchptr, which the @master
389 : * aggregate driver needs to function. The list of component matches pointed to
390 : * by @matchptr must be initialized to NULL before adding the first match. This
391 : * only matches against components added with component_add().
392 : *
393 : * The allocated match list in @matchptr is automatically released using devm
394 : * actions, where upon @release will be called to free any references held by
395 : * @compare_data, e.g. when @compare_data is a &device_node that must be
396 : * released with of_node_put().
397 : *
398 : * See also component_match_add() and component_match_add_typed().
399 : */
400 0 : void component_match_add_release(struct device *master,
401 : struct component_match **matchptr,
402 : void (*release)(struct device *, void *),
403 : int (*compare)(struct device *, void *), void *compare_data)
404 : {
405 0 : __component_match_add(master, matchptr, release, compare, NULL,
406 : compare_data);
407 0 : }
408 : EXPORT_SYMBOL(component_match_add_release);
409 :
410 : /**
411 : * component_match_add_typed - add a component match entry for a typed component
412 : * @master: device with the aggregate driver
413 : * @matchptr: pointer to the list of component matches
414 : * @compare_typed: compare function to match against all typed components
415 : * @compare_data: opaque pointer passed to the @compare function
416 : *
417 : * Adds a new component match to the list stored in @matchptr, which the @master
418 : * aggregate driver needs to function. The list of component matches pointed to
419 : * by @matchptr must be initialized to NULL before adding the first match. This
420 : * only matches against components added with component_add_typed().
421 : *
422 : * The allocated match list in @matchptr is automatically released using devm
423 : * actions.
424 : *
425 : * See also component_match_add_release() and component_match_add_typed().
426 : */
427 0 : void component_match_add_typed(struct device *master,
428 : struct component_match **matchptr,
429 : int (*compare_typed)(struct device *, int, void *), void *compare_data)
430 : {
431 0 : __component_match_add(master, matchptr, NULL, NULL, compare_typed,
432 : compare_data);
433 0 : }
434 : EXPORT_SYMBOL(component_match_add_typed);
435 :
436 0 : static void free_master(struct master *master)
437 : {
438 0 : struct component_match *match = master->match;
439 0 : int i;
440 :
441 0 : component_master_debugfs_del(master);
442 0 : list_del(&master->node);
443 :
444 0 : if (match) {
445 0 : for (i = 0; i < match->num; i++) {
446 0 : struct component *c = match->compare[i].component;
447 0 : if (c)
448 0 : c->master = NULL;
449 : }
450 : }
451 :
452 0 : kfree(master);
453 0 : }
454 :
455 : /**
456 : * component_master_add_with_match - register an aggregate driver
457 : * @dev: device with the aggregate driver
458 : * @ops: callbacks for the aggregate driver
459 : * @match: component match list for the aggregate driver
460 : *
461 : * Registers a new aggregate driver consisting of the components added to @match
462 : * by calling one of the component_match_add() functions. Once all components in
463 : * @match are available, it will be assembled by calling
464 : * &component_master_ops.bind from @ops. Must be unregistered by calling
465 : * component_master_del().
466 : */
467 0 : int component_master_add_with_match(struct device *dev,
468 : const struct component_master_ops *ops,
469 : struct component_match *match)
470 : {
471 0 : struct master *master;
472 0 : int ret;
473 :
474 : /* Reallocate the match array for its true size */
475 0 : ret = component_match_realloc(dev, match, match->num);
476 0 : if (ret)
477 : return ret;
478 :
479 0 : master = kzalloc(sizeof(*master), GFP_KERNEL);
480 0 : if (!master)
481 : return -ENOMEM;
482 :
483 0 : master->dev = dev;
484 0 : master->ops = ops;
485 0 : master->match = match;
486 :
487 0 : component_master_debugfs_add(master);
488 : /* Add to the list of available masters. */
489 0 : mutex_lock(&component_mutex);
490 0 : list_add(&master->node, &masters);
491 :
492 0 : ret = try_to_bring_up_master(master, NULL);
493 :
494 0 : if (ret < 0)
495 0 : free_master(master);
496 :
497 0 : mutex_unlock(&component_mutex);
498 :
499 0 : return ret < 0 ? ret : 0;
500 : }
501 : EXPORT_SYMBOL_GPL(component_master_add_with_match);
502 :
503 : /**
504 : * component_master_del - unregister an aggregate driver
505 : * @dev: device with the aggregate driver
506 : * @ops: callbacks for the aggregate driver
507 : *
508 : * Unregisters an aggregate driver registered with
509 : * component_master_add_with_match(). If necessary the aggregate driver is first
510 : * disassembled by calling &component_master_ops.unbind from @ops.
511 : */
512 0 : void component_master_del(struct device *dev,
513 : const struct component_master_ops *ops)
514 : {
515 0 : struct master *master;
516 :
517 0 : mutex_lock(&component_mutex);
518 0 : master = __master_find(dev, ops);
519 0 : if (master) {
520 0 : take_down_master(master);
521 0 : free_master(master);
522 : }
523 0 : mutex_unlock(&component_mutex);
524 0 : }
525 : EXPORT_SYMBOL_GPL(component_master_del);
526 :
527 0 : static void component_unbind(struct component *component,
528 : struct master *master, void *data)
529 : {
530 0 : WARN_ON(!component->bound);
531 :
532 0 : if (component->ops && component->ops->unbind)
533 0 : component->ops->unbind(component->dev, master->dev, data);
534 0 : component->bound = false;
535 :
536 : /* Release all resources claimed in the binding of this component */
537 0 : devres_release_group(component->dev, component);
538 0 : }
539 :
540 : /**
541 : * component_unbind_all - unbind all components of an aggregate driver
542 : * @master_dev: device with the aggregate driver
543 : * @data: opaque pointer, passed to all components
544 : *
545 : * Unbinds all components of the aggregate @dev by passing @data to their
546 : * &component_ops.unbind functions. Should be called from
547 : * &component_master_ops.unbind.
548 : */
549 0 : void component_unbind_all(struct device *master_dev, void *data)
550 : {
551 0 : struct master *master;
552 0 : struct component *c;
553 0 : size_t i;
554 :
555 0 : WARN_ON(!mutex_is_locked(&component_mutex));
556 :
557 0 : master = __master_find(master_dev, NULL);
558 0 : if (!master)
559 : return;
560 :
561 : /* Unbind components in reverse order */
562 0 : for (i = master->match->num; i--; )
563 0 : if (!master->match->compare[i].duplicate) {
564 0 : c = master->match->compare[i].component;
565 0 : component_unbind(c, master, data);
566 : }
567 : }
568 : EXPORT_SYMBOL_GPL(component_unbind_all);
569 :
570 0 : static int component_bind(struct component *component, struct master *master,
571 : void *data)
572 : {
573 0 : int ret;
574 :
575 : /*
576 : * Each component initialises inside its own devres group.
577 : * This allows us to roll-back a failed component without
578 : * affecting anything else.
579 : */
580 0 : if (!devres_open_group(master->dev, NULL, GFP_KERNEL))
581 : return -ENOMEM;
582 :
583 : /*
584 : * Also open a group for the device itself: this allows us
585 : * to release the resources claimed against the sub-device
586 : * at the appropriate moment.
587 : */
588 0 : if (!devres_open_group(component->dev, component, GFP_KERNEL)) {
589 0 : devres_release_group(master->dev, NULL);
590 0 : return -ENOMEM;
591 : }
592 :
593 0 : dev_dbg(master->dev, "binding %s (ops %ps)\n",
594 : dev_name(component->dev), component->ops);
595 :
596 0 : ret = component->ops->bind(component->dev, master->dev, data);
597 0 : if (!ret) {
598 0 : component->bound = true;
599 :
600 : /*
601 : * Close the component device's group so that resources
602 : * allocated in the binding are encapsulated for removal
603 : * at unbind. Remove the group on the DRM device as we
604 : * can clean those resources up independently.
605 : */
606 0 : devres_close_group(component->dev, NULL);
607 0 : devres_remove_group(master->dev, NULL);
608 :
609 0 : dev_info(master->dev, "bound %s (ops %ps)\n",
610 : dev_name(component->dev), component->ops);
611 : } else {
612 0 : devres_release_group(component->dev, NULL);
613 0 : devres_release_group(master->dev, NULL);
614 :
615 0 : if (ret != -EPROBE_DEFER)
616 0 : dev_err(master->dev, "failed to bind %s (ops %ps): %d\n",
617 : dev_name(component->dev), component->ops, ret);
618 : }
619 :
620 : return ret;
621 : }
622 :
623 : /**
624 : * component_bind_all - bind all components of an aggregate driver
625 : * @master_dev: device with the aggregate driver
626 : * @data: opaque pointer, passed to all components
627 : *
628 : * Binds all components of the aggregate @dev by passing @data to their
629 : * &component_ops.bind functions. Should be called from
630 : * &component_master_ops.bind.
631 : */
632 0 : int component_bind_all(struct device *master_dev, void *data)
633 : {
634 0 : struct master *master;
635 0 : struct component *c;
636 0 : size_t i;
637 0 : int ret = 0;
638 :
639 0 : WARN_ON(!mutex_is_locked(&component_mutex));
640 :
641 0 : master = __master_find(master_dev, NULL);
642 0 : if (!master)
643 : return -EINVAL;
644 :
645 : /* Bind components in match order */
646 0 : for (i = 0; i < master->match->num; i++)
647 0 : if (!master->match->compare[i].duplicate) {
648 0 : c = master->match->compare[i].component;
649 0 : ret = component_bind(c, master, data);
650 0 : if (ret)
651 : break;
652 : }
653 :
654 0 : if (ret != 0) {
655 0 : for (; i > 0; i--)
656 0 : if (!master->match->compare[i - 1].duplicate) {
657 0 : c = master->match->compare[i - 1].component;
658 0 : component_unbind(c, master, data);
659 : }
660 : }
661 :
662 : return ret;
663 : }
664 : EXPORT_SYMBOL_GPL(component_bind_all);
665 :
666 0 : static int __component_add(struct device *dev, const struct component_ops *ops,
667 : int subcomponent)
668 : {
669 0 : struct component *component;
670 0 : int ret;
671 :
672 0 : component = kzalloc(sizeof(*component), GFP_KERNEL);
673 0 : if (!component)
674 : return -ENOMEM;
675 :
676 0 : component->ops = ops;
677 0 : component->dev = dev;
678 0 : component->subcomponent = subcomponent;
679 :
680 0 : dev_dbg(dev, "adding component (ops %ps)\n", ops);
681 :
682 0 : mutex_lock(&component_mutex);
683 0 : list_add_tail(&component->node, &component_list);
684 :
685 0 : ret = try_to_bring_up_masters(component);
686 0 : if (ret < 0) {
687 0 : if (component->master)
688 0 : remove_component(component->master, component);
689 0 : list_del(&component->node);
690 :
691 0 : kfree(component);
692 : }
693 0 : mutex_unlock(&component_mutex);
694 :
695 0 : return ret < 0 ? ret : 0;
696 : }
697 :
698 : /**
699 : * component_add_typed - register a component
700 : * @dev: component device
701 : * @ops: component callbacks
702 : * @subcomponent: nonzero identifier for subcomponents
703 : *
704 : * Register a new component for @dev. Functions in @ops will be call when the
705 : * aggregate driver is ready to bind the overall driver by calling
706 : * component_bind_all(). See also &struct component_ops.
707 : *
708 : * @subcomponent must be nonzero and is used to differentiate between multiple
709 : * components registerd on the same device @dev. These components are match
710 : * using component_match_add_typed().
711 : *
712 : * The component needs to be unregistered at driver unload/disconnect by
713 : * calling component_del().
714 : *
715 : * See also component_add().
716 : */
717 0 : int component_add_typed(struct device *dev, const struct component_ops *ops,
718 : int subcomponent)
719 : {
720 0 : if (WARN_ON(subcomponent == 0))
721 : return -EINVAL;
722 :
723 0 : return __component_add(dev, ops, subcomponent);
724 : }
725 : EXPORT_SYMBOL_GPL(component_add_typed);
726 :
727 : /**
728 : * component_add - register a component
729 : * @dev: component device
730 : * @ops: component callbacks
731 : *
732 : * Register a new component for @dev. Functions in @ops will be called when the
733 : * aggregate driver is ready to bind the overall driver by calling
734 : * component_bind_all(). See also &struct component_ops.
735 : *
736 : * The component needs to be unregistered at driver unload/disconnect by
737 : * calling component_del().
738 : *
739 : * See also component_add_typed() for a variant that allows multipled different
740 : * components on the same device.
741 : */
742 0 : int component_add(struct device *dev, const struct component_ops *ops)
743 : {
744 0 : return __component_add(dev, ops, 0);
745 : }
746 : EXPORT_SYMBOL_GPL(component_add);
747 :
748 : /**
749 : * component_del - unregister a component
750 : * @dev: component device
751 : * @ops: component callbacks
752 : *
753 : * Unregister a component added with component_add(). If the component is bound
754 : * into an aggregate driver, this will force the entire aggregate driver, including
755 : * all its components, to be unbound.
756 : */
757 0 : void component_del(struct device *dev, const struct component_ops *ops)
758 : {
759 0 : struct component *c, *component = NULL;
760 :
761 0 : mutex_lock(&component_mutex);
762 0 : list_for_each_entry(c, &component_list, node)
763 0 : if (c->dev == dev && c->ops == ops) {
764 0 : list_del(&c->node);
765 0 : component = c;
766 0 : break;
767 : }
768 :
769 0 : if (component && component->master) {
770 0 : take_down_master(component->master);
771 0 : remove_component(component->master, component);
772 : }
773 :
774 0 : mutex_unlock(&component_mutex);
775 :
776 0 : WARN_ON(!component);
777 0 : kfree(component);
778 0 : }
779 : EXPORT_SYMBOL_GPL(component_del);
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