1 // SPDX-License-Identifier: GPL-2.0-only
2 /* The industrial I/O core, trigger handling functions
3  *
4  * Copyright (c) 2008 Jonathan Cameron
5  */
6 
7 #include <linux/kernel.h>
8 #include <linux/idr.h>
9 #include <linux/err.h>
10 #include <linux/device.h>
11 #include <linux/interrupt.h>
12 #include <linux/list.h>
13 #include <linux/slab.h>
14 
15 #include <linux/iio/iio.h>
16 #include <linux/iio/trigger.h>
17 #include "iio_core.h"
18 #include "iio_core_trigger.h"
19 #include <linux/iio/trigger_consumer.h>
20 
21 /* RFC - Question of approach
22  * Make the common case (single sensor single trigger)
23  * simple by starting trigger capture from when first sensors
24  * is added.
25  *
26  * Complex simultaneous start requires use of 'hold' functionality
27  * of the trigger. (not implemented)
28  *
29  * Any other suggestions?
30  */
31 
32 static DEFINE_IDA(iio_trigger_ida);
33 
34 /* Single list of all available triggers */
35 static LIST_HEAD(iio_trigger_list);
36 static DEFINE_MUTEX(iio_trigger_list_lock);
37 
38 /**
39  * iio_trigger_read_name() - retrieve useful identifying name
40  * @dev:	device associated with the iio_trigger
41  * @attr:	pointer to the device_attribute structure that is
42  *		being processed
43  * @buf:	buffer to print the name into
44  *
45  * Return: a negative number on failure or the number of written
46  *	   characters on success.
47  */
48 static ssize_t iio_trigger_read_name(struct device *dev,
49 				     struct device_attribute *attr,
50 				     char *buf)
51 {
52 	struct iio_trigger *trig = to_iio_trigger(dev);
53 	return sprintf(buf, "%s\n", trig->name);
54 }
55 
56 static DEVICE_ATTR(name, S_IRUGO, iio_trigger_read_name, NULL);
57 
58 static struct attribute *iio_trig_dev_attrs[] = {
59 	&dev_attr_name.attr,
60 	NULL,
61 };
62 ATTRIBUTE_GROUPS(iio_trig_dev);
63 
64 static struct iio_trigger *__iio_trigger_find_by_name(const char *name);
65 
66 int __iio_trigger_register(struct iio_trigger *trig_info,
67 			   struct module *this_mod)
68 {
69 	int ret;
70 
71 	trig_info->owner = this_mod;
72 
73 	trig_info->id = ida_simple_get(&iio_trigger_ida, 0, 0, GFP_KERNEL);
74 	if (trig_info->id < 0)
75 		return trig_info->id;
76 
77 	/* Set the name used for the sysfs directory etc */
78 	dev_set_name(&trig_info->dev, "trigger%ld",
79 		     (unsigned long) trig_info->id);
80 
81 	ret = device_add(&trig_info->dev);
82 	if (ret)
83 		goto error_unregister_id;
84 
85 	/* Add to list of available triggers held by the IIO core */
86 	mutex_lock(&iio_trigger_list_lock);
87 	if (__iio_trigger_find_by_name(trig_info->name)) {
88 		pr_err("Duplicate trigger name '%s'\n", trig_info->name);
89 		ret = -EEXIST;
90 		goto error_device_del;
91 	}
92 	list_add_tail(&trig_info->list, &iio_trigger_list);
93 	mutex_unlock(&iio_trigger_list_lock);
94 
95 	return 0;
96 
97 error_device_del:
98 	mutex_unlock(&iio_trigger_list_lock);
99 	device_del(&trig_info->dev);
100 error_unregister_id:
101 	ida_simple_remove(&iio_trigger_ida, trig_info->id);
102 	return ret;
103 }
104 EXPORT_SYMBOL(__iio_trigger_register);
105 
106 void iio_trigger_unregister(struct iio_trigger *trig_info)
107 {
108 	mutex_lock(&iio_trigger_list_lock);
109 	list_del(&trig_info->list);
110 	mutex_unlock(&iio_trigger_list_lock);
111 
112 	ida_simple_remove(&iio_trigger_ida, trig_info->id);
113 	/* Possible issue in here */
114 	device_del(&trig_info->dev);
115 }
116 EXPORT_SYMBOL(iio_trigger_unregister);
117 
118 int iio_trigger_set_immutable(struct iio_dev *indio_dev, struct iio_trigger *trig)
119 {
120 	if (!indio_dev || !trig)
121 		return -EINVAL;
122 
123 	mutex_lock(&indio_dev->mlock);
124 	WARN_ON(indio_dev->trig_readonly);
125 
126 	indio_dev->trig = iio_trigger_get(trig);
127 	indio_dev->trig_readonly = true;
128 	mutex_unlock(&indio_dev->mlock);
129 
130 	return 0;
131 }
132 EXPORT_SYMBOL(iio_trigger_set_immutable);
133 
134 /* Search for trigger by name, assuming iio_trigger_list_lock held */
135 static struct iio_trigger *__iio_trigger_find_by_name(const char *name)
136 {
137 	struct iio_trigger *iter;
138 
139 	list_for_each_entry(iter, &iio_trigger_list, list)
140 		if (!strcmp(iter->name, name))
141 			return iter;
142 
143 	return NULL;
144 }
145 
146 static struct iio_trigger *iio_trigger_acquire_by_name(const char *name)
147 {
148 	struct iio_trigger *trig = NULL, *iter;
149 
150 	mutex_lock(&iio_trigger_list_lock);
151 	list_for_each_entry(iter, &iio_trigger_list, list)
152 		if (sysfs_streq(iter->name, name)) {
153 			trig = iter;
154 			iio_trigger_get(trig);
155 			break;
156 		}
157 	mutex_unlock(&iio_trigger_list_lock);
158 
159 	return trig;
160 }
161 
162 void iio_trigger_poll(struct iio_trigger *trig)
163 {
164 	int i;
165 
166 	if (!atomic_read(&trig->use_count)) {
167 		atomic_set(&trig->use_count, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
168 
169 		for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
170 			if (trig->subirqs[i].enabled)
171 				generic_handle_irq(trig->subirq_base + i);
172 			else
173 				iio_trigger_notify_done(trig);
174 		}
175 	}
176 }
177 EXPORT_SYMBOL(iio_trigger_poll);
178 
179 irqreturn_t iio_trigger_generic_data_rdy_poll(int irq, void *private)
180 {
181 	iio_trigger_poll(private);
182 	return IRQ_HANDLED;
183 }
184 EXPORT_SYMBOL(iio_trigger_generic_data_rdy_poll);
185 
186 void iio_trigger_poll_chained(struct iio_trigger *trig)
187 {
188 	int i;
189 
190 	if (!atomic_read(&trig->use_count)) {
191 		atomic_set(&trig->use_count, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
192 
193 		for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
194 			if (trig->subirqs[i].enabled)
195 				handle_nested_irq(trig->subirq_base + i);
196 			else
197 				iio_trigger_notify_done(trig);
198 		}
199 	}
200 }
201 EXPORT_SYMBOL(iio_trigger_poll_chained);
202 
203 void iio_trigger_notify_done(struct iio_trigger *trig)
204 {
205 	if (atomic_dec_and_test(&trig->use_count) && trig->ops &&
206 	    trig->ops->reenable)
207 		trig->ops->reenable(trig);
208 }
209 EXPORT_SYMBOL(iio_trigger_notify_done);
210 
211 /* Trigger Consumer related functions */
212 static int iio_trigger_get_irq(struct iio_trigger *trig)
213 {
214 	int ret;
215 	mutex_lock(&trig->pool_lock);
216 	ret = bitmap_find_free_region(trig->pool,
217 				      CONFIG_IIO_CONSUMERS_PER_TRIGGER,
218 				      ilog2(1));
219 	mutex_unlock(&trig->pool_lock);
220 	if (ret >= 0)
221 		ret += trig->subirq_base;
222 
223 	return ret;
224 }
225 
226 static void iio_trigger_put_irq(struct iio_trigger *trig, int irq)
227 {
228 	mutex_lock(&trig->pool_lock);
229 	clear_bit(irq - trig->subirq_base, trig->pool);
230 	mutex_unlock(&trig->pool_lock);
231 }
232 
233 /* Complexity in here.  With certain triggers (datardy) an acknowledgement
234  * may be needed if the pollfuncs do not include the data read for the
235  * triggering device.
236  * This is not currently handled.  Alternative of not enabling trigger unless
237  * the relevant function is in there may be the best option.
238  */
239 /* Worth protecting against double additions? */
240 int iio_trigger_attach_poll_func(struct iio_trigger *trig,
241 				 struct iio_poll_func *pf)
242 {
243 	int ret = 0;
244 	bool notinuse
245 		= bitmap_empty(trig->pool, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
246 
247 	/* Prevent the module from being removed whilst attached to a trigger */
248 	__module_get(pf->indio_dev->driver_module);
249 
250 	/* Get irq number */
251 	pf->irq = iio_trigger_get_irq(trig);
252 	if (pf->irq < 0) {
253 		pr_err("Could not find an available irq for trigger %s, CONFIG_IIO_CONSUMERS_PER_TRIGGER=%d limit might be exceeded\n",
254 			trig->name, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
255 		goto out_put_module;
256 	}
257 
258 	/* Request irq */
259 	ret = request_threaded_irq(pf->irq, pf->h, pf->thread,
260 				   pf->type, pf->name,
261 				   pf);
262 	if (ret < 0)
263 		goto out_put_irq;
264 
265 	/* Enable trigger in driver */
266 	if (trig->ops && trig->ops->set_trigger_state && notinuse) {
267 		ret = trig->ops->set_trigger_state(trig, true);
268 		if (ret < 0)
269 			goto out_free_irq;
270 	}
271 
272 	/*
273 	 * Check if we just registered to our own trigger: we determine that
274 	 * this is the case if the IIO device and the trigger device share the
275 	 * same parent device.
276 	 */
277 	if (pf->indio_dev->dev.parent == trig->dev.parent)
278 		trig->attached_own_device = true;
279 
280 	return ret;
281 
282 out_free_irq:
283 	free_irq(pf->irq, pf);
284 out_put_irq:
285 	iio_trigger_put_irq(trig, pf->irq);
286 out_put_module:
287 	module_put(pf->indio_dev->driver_module);
288 	return ret;
289 }
290 
291 int iio_trigger_detach_poll_func(struct iio_trigger *trig,
292 				 struct iio_poll_func *pf)
293 {
294 	int ret = 0;
295 	bool no_other_users
296 		= (bitmap_weight(trig->pool,
297 				 CONFIG_IIO_CONSUMERS_PER_TRIGGER)
298 		   == 1);
299 	if (trig->ops && trig->ops->set_trigger_state && no_other_users) {
300 		ret = trig->ops->set_trigger_state(trig, false);
301 		if (ret)
302 			return ret;
303 	}
304 	if (pf->indio_dev->dev.parent == trig->dev.parent)
305 		trig->attached_own_device = false;
306 	iio_trigger_put_irq(trig, pf->irq);
307 	free_irq(pf->irq, pf);
308 	module_put(pf->indio_dev->driver_module);
309 
310 	return ret;
311 }
312 
313 irqreturn_t iio_pollfunc_store_time(int irq, void *p)
314 {
315 	struct iio_poll_func *pf = p;
316 	pf->timestamp = iio_get_time_ns(pf->indio_dev);
317 	return IRQ_WAKE_THREAD;
318 }
319 EXPORT_SYMBOL(iio_pollfunc_store_time);
320 
321 struct iio_poll_func
322 *iio_alloc_pollfunc(irqreturn_t (*h)(int irq, void *p),
323 		    irqreturn_t (*thread)(int irq, void *p),
324 		    int type,
325 		    struct iio_dev *indio_dev,
326 		    const char *fmt,
327 		    ...)
328 {
329 	va_list vargs;
330 	struct iio_poll_func *pf;
331 
332 	pf = kmalloc(sizeof *pf, GFP_KERNEL);
333 	if (pf == NULL)
334 		return NULL;
335 	va_start(vargs, fmt);
336 	pf->name = kvasprintf(GFP_KERNEL, fmt, vargs);
337 	va_end(vargs);
338 	if (pf->name == NULL) {
339 		kfree(pf);
340 		return NULL;
341 	}
342 	pf->h = h;
343 	pf->thread = thread;
344 	pf->type = type;
345 	pf->indio_dev = indio_dev;
346 
347 	return pf;
348 }
349 EXPORT_SYMBOL_GPL(iio_alloc_pollfunc);
350 
351 void iio_dealloc_pollfunc(struct iio_poll_func *pf)
352 {
353 	kfree(pf->name);
354 	kfree(pf);
355 }
356 EXPORT_SYMBOL_GPL(iio_dealloc_pollfunc);
357 
358 /**
359  * iio_trigger_read_current() - trigger consumer sysfs query current trigger
360  * @dev:	device associated with an industrial I/O device
361  * @attr:	pointer to the device_attribute structure that
362  *		is being processed
363  * @buf:	buffer where the current trigger name will be printed into
364  *
365  * For trigger consumers the current_trigger interface allows the trigger
366  * used by the device to be queried.
367  *
368  * Return: a negative number on failure, the number of characters written
369  *	   on success or 0 if no trigger is available
370  */
371 static ssize_t iio_trigger_read_current(struct device *dev,
372 					struct device_attribute *attr,
373 					char *buf)
374 {
375 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
376 
377 	if (indio_dev->trig)
378 		return sprintf(buf, "%s\n", indio_dev->trig->name);
379 	return 0;
380 }
381 
382 /**
383  * iio_trigger_write_current() - trigger consumer sysfs set current trigger
384  * @dev:	device associated with an industrial I/O device
385  * @attr:	device attribute that is being processed
386  * @buf:	string buffer that holds the name of the trigger
387  * @len:	length of the trigger name held by buf
388  *
389  * For trigger consumers the current_trigger interface allows the trigger
390  * used for this device to be specified at run time based on the trigger's
391  * name.
392  *
393  * Return: negative error code on failure or length of the buffer
394  *	   on success
395  */
396 static ssize_t iio_trigger_write_current(struct device *dev,
397 					 struct device_attribute *attr,
398 					 const char *buf,
399 					 size_t len)
400 {
401 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
402 	struct iio_trigger *oldtrig = indio_dev->trig;
403 	struct iio_trigger *trig;
404 	int ret;
405 
406 	mutex_lock(&indio_dev->mlock);
407 	if (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED) {
408 		mutex_unlock(&indio_dev->mlock);
409 		return -EBUSY;
410 	}
411 	if (indio_dev->trig_readonly) {
412 		mutex_unlock(&indio_dev->mlock);
413 		return -EPERM;
414 	}
415 	mutex_unlock(&indio_dev->mlock);
416 
417 	trig = iio_trigger_acquire_by_name(buf);
418 	if (oldtrig == trig) {
419 		ret = len;
420 		goto out_trigger_put;
421 	}
422 
423 	if (trig && indio_dev->info->validate_trigger) {
424 		ret = indio_dev->info->validate_trigger(indio_dev, trig);
425 		if (ret)
426 			goto out_trigger_put;
427 	}
428 
429 	if (trig && trig->ops && trig->ops->validate_device) {
430 		ret = trig->ops->validate_device(trig, indio_dev);
431 		if (ret)
432 			goto out_trigger_put;
433 	}
434 
435 	indio_dev->trig = trig;
436 
437 	if (oldtrig) {
438 		if (indio_dev->modes & INDIO_EVENT_TRIGGERED)
439 			iio_trigger_detach_poll_func(oldtrig,
440 						     indio_dev->pollfunc_event);
441 		iio_trigger_put(oldtrig);
442 	}
443 	if (indio_dev->trig) {
444 		if (indio_dev->modes & INDIO_EVENT_TRIGGERED)
445 			iio_trigger_attach_poll_func(indio_dev->trig,
446 						     indio_dev->pollfunc_event);
447 	}
448 
449 	return len;
450 
451 out_trigger_put:
452 	if (trig)
453 		iio_trigger_put(trig);
454 	return ret;
455 }
456 
457 static DEVICE_ATTR(current_trigger, S_IRUGO | S_IWUSR,
458 		   iio_trigger_read_current,
459 		   iio_trigger_write_current);
460 
461 static struct attribute *iio_trigger_consumer_attrs[] = {
462 	&dev_attr_current_trigger.attr,
463 	NULL,
464 };
465 
466 static const struct attribute_group iio_trigger_consumer_attr_group = {
467 	.name = "trigger",
468 	.attrs = iio_trigger_consumer_attrs,
469 };
470 
471 static void iio_trig_release(struct device *device)
472 {
473 	struct iio_trigger *trig = to_iio_trigger(device);
474 	int i;
475 
476 	if (trig->subirq_base) {
477 		for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
478 			irq_modify_status(trig->subirq_base + i,
479 					  IRQ_NOAUTOEN,
480 					  IRQ_NOREQUEST | IRQ_NOPROBE);
481 			irq_set_chip(trig->subirq_base + i,
482 				     NULL);
483 			irq_set_handler(trig->subirq_base + i,
484 					NULL);
485 		}
486 
487 		irq_free_descs(trig->subirq_base,
488 			       CONFIG_IIO_CONSUMERS_PER_TRIGGER);
489 	}
490 	kfree(trig->name);
491 	kfree(trig);
492 }
493 
494 static const struct device_type iio_trig_type = {
495 	.release = iio_trig_release,
496 	.groups = iio_trig_dev_groups,
497 };
498 
499 static void iio_trig_subirqmask(struct irq_data *d)
500 {
501 	struct irq_chip *chip = irq_data_get_irq_chip(d);
502 	struct iio_trigger *trig
503 		= container_of(chip,
504 			       struct iio_trigger, subirq_chip);
505 	trig->subirqs[d->irq - trig->subirq_base].enabled = false;
506 }
507 
508 static void iio_trig_subirqunmask(struct irq_data *d)
509 {
510 	struct irq_chip *chip = irq_data_get_irq_chip(d);
511 	struct iio_trigger *trig
512 		= container_of(chip,
513 			       struct iio_trigger, subirq_chip);
514 	trig->subirqs[d->irq - trig->subirq_base].enabled = true;
515 }
516 
517 static __printf(1, 0)
518 struct iio_trigger *viio_trigger_alloc(const char *fmt, va_list vargs)
519 {
520 	struct iio_trigger *trig;
521 	int i;
522 
523 	trig = kzalloc(sizeof *trig, GFP_KERNEL);
524 	if (!trig)
525 		return NULL;
526 
527 	trig->dev.type = &iio_trig_type;
528 	trig->dev.bus = &iio_bus_type;
529 	device_initialize(&trig->dev);
530 
531 	mutex_init(&trig->pool_lock);
532 	trig->subirq_base = irq_alloc_descs(-1, 0,
533 					    CONFIG_IIO_CONSUMERS_PER_TRIGGER,
534 					    0);
535 	if (trig->subirq_base < 0)
536 		goto free_trig;
537 
538 	trig->name = kvasprintf(GFP_KERNEL, fmt, vargs);
539 	if (trig->name == NULL)
540 		goto free_descs;
541 
542 	trig->subirq_chip.name = trig->name;
543 	trig->subirq_chip.irq_mask = &iio_trig_subirqmask;
544 	trig->subirq_chip.irq_unmask = &iio_trig_subirqunmask;
545 	for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
546 		irq_set_chip(trig->subirq_base + i, &trig->subirq_chip);
547 		irq_set_handler(trig->subirq_base + i, &handle_simple_irq);
548 		irq_modify_status(trig->subirq_base + i,
549 				  IRQ_NOREQUEST | IRQ_NOAUTOEN, IRQ_NOPROBE);
550 	}
551 	get_device(&trig->dev);
552 
553 	return trig;
554 
555 free_descs:
556 	irq_free_descs(trig->subirq_base, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
557 free_trig:
558 	kfree(trig);
559 	return NULL;
560 }
561 
562 struct iio_trigger *iio_trigger_alloc(const char *fmt, ...)
563 {
564 	struct iio_trigger *trig;
565 	va_list vargs;
566 
567 	va_start(vargs, fmt);
568 	trig = viio_trigger_alloc(fmt, vargs);
569 	va_end(vargs);
570 
571 	return trig;
572 }
573 EXPORT_SYMBOL(iio_trigger_alloc);
574 
575 void iio_trigger_free(struct iio_trigger *trig)
576 {
577 	if (trig)
578 		put_device(&trig->dev);
579 }
580 EXPORT_SYMBOL(iio_trigger_free);
581 
582 static void devm_iio_trigger_release(struct device *dev, void *res)
583 {
584 	iio_trigger_free(*(struct iio_trigger **)res);
585 }
586 
587 /**
588  * devm_iio_trigger_alloc - Resource-managed iio_trigger_alloc()
589  * @dev:		Device to allocate iio_trigger for
590  * @fmt:		trigger name format. If it includes format
591  *			specifiers, the additional arguments following
592  *			format are formatted and inserted in the resulting
593  *			string replacing their respective specifiers.
594  *
595  * Managed iio_trigger_alloc.  iio_trigger allocated with this function is
596  * automatically freed on driver detach.
597  *
598  * RETURNS:
599  * Pointer to allocated iio_trigger on success, NULL on failure.
600  */
601 struct iio_trigger *devm_iio_trigger_alloc(struct device *dev,
602 						const char *fmt, ...)
603 {
604 	struct iio_trigger **ptr, *trig;
605 	va_list vargs;
606 
607 	ptr = devres_alloc(devm_iio_trigger_release, sizeof(*ptr),
608 			   GFP_KERNEL);
609 	if (!ptr)
610 		return NULL;
611 
612 	/* use raw alloc_dr for kmalloc caller tracing */
613 	va_start(vargs, fmt);
614 	trig = viio_trigger_alloc(fmt, vargs);
615 	va_end(vargs);
616 	if (trig) {
617 		*ptr = trig;
618 		devres_add(dev, ptr);
619 	} else {
620 		devres_free(ptr);
621 	}
622 
623 	return trig;
624 }
625 EXPORT_SYMBOL_GPL(devm_iio_trigger_alloc);
626 
627 static void devm_iio_trigger_unreg(struct device *dev, void *res)
628 {
629 	iio_trigger_unregister(*(struct iio_trigger **)res);
630 }
631 
632 /**
633  * __devm_iio_trigger_register - Resource-managed iio_trigger_register()
634  * @dev:	device this trigger was allocated for
635  * @trig_info:	trigger to register
636  * @this_mod:   module registering the trigger
637  *
638  * Managed iio_trigger_register().  The IIO trigger registered with this
639  * function is automatically unregistered on driver detach. This function
640  * calls iio_trigger_register() internally. Refer to that function for more
641  * information.
642  *
643  * RETURNS:
644  * 0 on success, negative error number on failure.
645  */
646 int __devm_iio_trigger_register(struct device *dev,
647 				struct iio_trigger *trig_info,
648 				struct module *this_mod)
649 {
650 	struct iio_trigger **ptr;
651 	int ret;
652 
653 	ptr = devres_alloc(devm_iio_trigger_unreg, sizeof(*ptr), GFP_KERNEL);
654 	if (!ptr)
655 		return -ENOMEM;
656 
657 	*ptr = trig_info;
658 	ret = __iio_trigger_register(trig_info, this_mod);
659 	if (!ret)
660 		devres_add(dev, ptr);
661 	else
662 		devres_free(ptr);
663 
664 	return ret;
665 }
666 EXPORT_SYMBOL_GPL(__devm_iio_trigger_register);
667 
668 bool iio_trigger_using_own(struct iio_dev *indio_dev)
669 {
670 	return indio_dev->trig->attached_own_device;
671 }
672 EXPORT_SYMBOL(iio_trigger_using_own);
673 
674 /**
675  * iio_trigger_validate_own_device - Check if a trigger and IIO device belong to
676  *  the same device
677  * @trig: The IIO trigger to check
678  * @indio_dev: the IIO device to check
679  *
680  * This function can be used as the validate_device callback for triggers that
681  * can only be attached to their own device.
682  *
683  * Return: 0 if both the trigger and the IIO device belong to the same
684  * device, -EINVAL otherwise.
685  */
686 int iio_trigger_validate_own_device(struct iio_trigger *trig,
687 	struct iio_dev *indio_dev)
688 {
689 	if (indio_dev->dev.parent != trig->dev.parent)
690 		return -EINVAL;
691 	return 0;
692 }
693 EXPORT_SYMBOL(iio_trigger_validate_own_device);
694 
695 void iio_device_register_trigger_consumer(struct iio_dev *indio_dev)
696 {
697 	indio_dev->groups[indio_dev->groupcounter++] =
698 		&iio_trigger_consumer_attr_group;
699 }
700 
701 void iio_device_unregister_trigger_consumer(struct iio_dev *indio_dev)
702 {
703 	/* Clean up an associated but not attached trigger reference */
704 	if (indio_dev->trig)
705 		iio_trigger_put(indio_dev->trig);
706 }
707