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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/cleanup.h>
8#include <linux/kernel.h>
9#include <linux/idr.h>
10#include <linux/err.h>
11#include <linux/device.h>
12#include <linux/interrupt.h>
13#include <linux/list.h>
14#include <linux/slab.h>
15
16#include <linux/iio/iio.h>
17#include <linux/iio/iio-opaque.h>
18#include <linux/iio/trigger.h>
19#include "iio_core.h"
20#include "iio_core_trigger.h"
21#include <linux/iio/trigger_consumer.h>
22
23/* RFC - Question of approach
24 * Make the common case (single sensor single trigger)
25 * simple by starting trigger capture from when first sensors
26 * is added.
27 *
28 * Complex simultaneous start requires use of 'hold' functionality
29 * of the trigger. (not implemented)
30 *
31 * Any other suggestions?
32 */
33
34static DEFINE_IDA(iio_trigger_ida);
35
36/* Single list of all available triggers */
37static LIST_HEAD(iio_trigger_list);
38static DEFINE_MUTEX(iio_trigger_list_lock);
39
40/**
41 * name_show() - retrieve useful identifying name
42 * @dev: device associated with the iio_trigger
43 * @attr: pointer to the device_attribute structure that is
44 * being processed
45 * @buf: buffer to print the name into
46 *
47 * Return: a negative number on failure or the number of written
48 * characters on success.
49 */
50static ssize_t name_show(struct device *dev, struct device_attribute *attr,
51 char *buf)
52{
53 struct iio_trigger *trig = to_iio_trigger(dev);
54
55 return sysfs_emit(buf, "%s\n", trig->name);
56}
57
58static DEVICE_ATTR_RO(name);
59
60static struct attribute *iio_trig_dev_attrs[] = {
61 &dev_attr_name.attr,
62 NULL,
63};
64ATTRIBUTE_GROUPS(iio_trig_dev);
65
66static struct iio_trigger *__iio_trigger_find_by_name(const char *name);
67
68int iio_trigger_register(struct iio_trigger *trig_info)
69{
70 int ret;
71
72 trig_info->id = ida_alloc(&iio_trigger_ida, GFP_KERNEL);
73 if (trig_info->id < 0)
74 return trig_info->id;
75
76 /* Set the name used for the sysfs directory etc */
77 dev_set_name(&trig_info->dev, "trigger%d", trig_info->id);
78
79 ret = device_add(&trig_info->dev);
80 if (ret)
81 goto error_unregister_id;
82
83 /* Add to list of available triggers held by the IIO core */
84 scoped_guard(mutex, &iio_trigger_list_lock) {
85 if (__iio_trigger_find_by_name(trig_info->name)) {
86 pr_err("Duplicate trigger name '%s'\n", trig_info->name);
87 ret = -EEXIST;
88 goto error_device_del;
89 }
90 list_add_tail(&trig_info->list, &iio_trigger_list);
91 }
92
93 return 0;
94
95error_device_del:
96 device_del(&trig_info->dev);
97error_unregister_id:
98 ida_free(&iio_trigger_ida, trig_info->id);
99 return ret;
100}
101EXPORT_SYMBOL(iio_trigger_register);
102
103void iio_trigger_unregister(struct iio_trigger *trig_info)
104{
105 scoped_guard(mutex, &iio_trigger_list_lock)
106 list_del(&trig_info->list);
107
108 ida_free(&iio_trigger_ida, trig_info->id);
109 /* Possible issue in here */
110 device_del(&trig_info->dev);
111}
112EXPORT_SYMBOL(iio_trigger_unregister);
113
114int iio_trigger_set_immutable(struct iio_dev *indio_dev, struct iio_trigger *trig)
115{
116 struct iio_dev_opaque *iio_dev_opaque;
117
118 if (!indio_dev || !trig)
119 return -EINVAL;
120
121 iio_dev_opaque = to_iio_dev_opaque(indio_dev);
122 guard(mutex)(&iio_dev_opaque->mlock);
123 WARN_ON(iio_dev_opaque->trig_readonly);
124
125 indio_dev->trig = iio_trigger_get(trig);
126 iio_dev_opaque->trig_readonly = true;
127
128 return 0;
129}
130EXPORT_SYMBOL(iio_trigger_set_immutable);
131
132/* Search for trigger by name, assuming iio_trigger_list_lock held */
133static struct iio_trigger *__iio_trigger_find_by_name(const char *name)
134{
135 struct iio_trigger *iter;
136
137 list_for_each_entry(iter, &iio_trigger_list, list)
138 if (!strcmp(iter->name, name))
139 return iter;
140
141 return NULL;
142}
143
144static struct iio_trigger *iio_trigger_acquire_by_name(const char *name)
145{
146 struct iio_trigger *iter;
147
148 guard(mutex)(&iio_trigger_list_lock);
149 list_for_each_entry(iter, &iio_trigger_list, list)
150 if (sysfs_streq(iter->name, name))
151 return iio_trigger_get(iter);
152
153 return NULL;
154}
155
156static void iio_reenable_work_fn(struct work_struct *work)
157{
158 struct iio_trigger *trig = container_of(work, struct iio_trigger,
159 reenable_work);
160
161 /*
162 * This 'might' occur after the trigger state is set to disabled -
163 * in that case the driver should skip reenabling.
164 */
165 trig->ops->reenable(trig);
166}
167
168/*
169 * In general, reenable callbacks may need to sleep and this path is
170 * not performance sensitive, so just queue up a work item
171 * to reneable the trigger for us.
172 *
173 * Races that can cause this.
174 * 1) A handler occurs entirely in interrupt context so the counter
175 * the final decrement is still in this interrupt.
176 * 2) The trigger has been removed, but one last interrupt gets through.
177 *
178 * For (1) we must call reenable, but not in atomic context.
179 * For (2) it should be safe to call reenanble, if drivers never blindly
180 * reenable after state is off.
181 */
182static void iio_trigger_notify_done_atomic(struct iio_trigger *trig)
183{
184 if (atomic_dec_and_test(&trig->use_count) && trig->ops &&
185 trig->ops->reenable)
186 schedule_work(&trig->reenable_work);
187}
188
189/**
190 * iio_trigger_poll() - Call the IRQ trigger handler of the consumers
191 * @trig: trigger which occurred
192 *
193 * This function should only be called from a hard IRQ context.
194 */
195void iio_trigger_poll(struct iio_trigger *trig)
196{
197 int i;
198
199 if (!atomic_read(&trig->use_count)) {
200 atomic_set(&trig->use_count, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
201
202 for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
203 if (trig->subirqs[i].enabled)
204 generic_handle_irq(trig->subirq_base + i);
205 else
206 iio_trigger_notify_done_atomic(trig);
207 }
208 }
209}
210EXPORT_SYMBOL(iio_trigger_poll);
211
212irqreturn_t iio_trigger_generic_data_rdy_poll(int irq, void *private)
213{
214 iio_trigger_poll(private);
215 return IRQ_HANDLED;
216}
217EXPORT_SYMBOL(iio_trigger_generic_data_rdy_poll);
218
219/**
220 * iio_trigger_poll_nested() - Call the threaded trigger handler of the
221 * consumers
222 * @trig: trigger which occurred
223 *
224 * This function should only be called from a kernel thread context.
225 */
226void iio_trigger_poll_nested(struct iio_trigger *trig)
227{
228 int i;
229
230 if (!atomic_read(&trig->use_count)) {
231 atomic_set(&trig->use_count, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
232
233 for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
234 if (trig->subirqs[i].enabled)
235 handle_nested_irq(trig->subirq_base + i);
236 else
237 iio_trigger_notify_done(trig);
238 }
239 }
240}
241EXPORT_SYMBOL(iio_trigger_poll_nested);
242
243void iio_trigger_notify_done(struct iio_trigger *trig)
244{
245 if (atomic_dec_and_test(&trig->use_count) && trig->ops &&
246 trig->ops->reenable)
247 trig->ops->reenable(trig);
248}
249EXPORT_SYMBOL(iio_trigger_notify_done);
250
251/* Trigger Consumer related functions */
252static int iio_trigger_get_irq(struct iio_trigger *trig)
253{
254 int ret;
255
256 scoped_guard(mutex, &trig->pool_lock) {
257 ret = bitmap_find_free_region(trig->pool,
258 CONFIG_IIO_CONSUMERS_PER_TRIGGER,
259 ilog2(1));
260 if (ret < 0)
261 return ret;
262 }
263
264 return ret + trig->subirq_base;
265}
266
267static void iio_trigger_put_irq(struct iio_trigger *trig, int irq)
268{
269 guard(mutex)(&trig->pool_lock);
270 clear_bit(irq - trig->subirq_base, trig->pool);
271}
272
273/* Complexity in here. With certain triggers (datardy) an acknowledgement
274 * may be needed if the pollfuncs do not include the data read for the
275 * triggering device.
276 * This is not currently handled. Alternative of not enabling trigger unless
277 * the relevant function is in there may be the best option.
278 */
279/* Worth protecting against double additions? */
280int iio_trigger_attach_poll_func(struct iio_trigger *trig,
281 struct iio_poll_func *pf)
282{
283 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(pf->indio_dev);
284 bool notinuse =
285 bitmap_empty(trig->pool, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
286 int ret = 0;
287
288 /* Prevent the module from being removed whilst attached to a trigger */
289 __module_get(iio_dev_opaque->driver_module);
290
291 /* Get irq number */
292 pf->irq = iio_trigger_get_irq(trig);
293 if (pf->irq < 0) {
294 pr_err("Could not find an available irq for trigger %s, CONFIG_IIO_CONSUMERS_PER_TRIGGER=%d limit might be exceeded\n",
295 trig->name, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
296 goto out_put_module;
297 }
298
299 /* Request irq */
300 ret = request_threaded_irq(pf->irq, pf->h, pf->thread,
301 pf->type, pf->name,
302 pf);
303 if (ret < 0)
304 goto out_put_irq;
305
306 /* Enable trigger in driver */
307 if (trig->ops && trig->ops->set_trigger_state && notinuse) {
308 ret = trig->ops->set_trigger_state(trig, true);
309 if (ret)
310 goto out_free_irq;
311 }
312
313 /*
314 * Check if we just registered to our own trigger: we determine that
315 * this is the case if the IIO device and the trigger device share the
316 * same parent device.
317 */
318 if (!iio_validate_own_trigger(pf->indio_dev, trig))
319 trig->attached_own_device = true;
320
321 return ret;
322
323out_free_irq:
324 free_irq(pf->irq, pf);
325out_put_irq:
326 iio_trigger_put_irq(trig, pf->irq);
327out_put_module:
328 module_put(iio_dev_opaque->driver_module);
329 return ret;
330}
331
332int iio_trigger_detach_poll_func(struct iio_trigger *trig,
333 struct iio_poll_func *pf)
334{
335 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(pf->indio_dev);
336 bool no_other_users =
337 bitmap_weight(trig->pool, CONFIG_IIO_CONSUMERS_PER_TRIGGER) == 1;
338 int ret = 0;
339
340 if (trig->ops && trig->ops->set_trigger_state && no_other_users) {
341 ret = trig->ops->set_trigger_state(trig, false);
342 if (ret)
343 return ret;
344 }
345 if (pf->indio_dev->dev.parent == trig->dev.parent)
346 trig->attached_own_device = false;
347 iio_trigger_put_irq(trig, pf->irq);
348 free_irq(pf->irq, pf);
349 module_put(iio_dev_opaque->driver_module);
350 pf->irq = 0;
351
352 return ret;
353}
354
355irqreturn_t iio_pollfunc_store_time(int irq, void *p)
356{
357 struct iio_poll_func *pf = p;
358
359 pf->timestamp = iio_get_time_ns(pf->indio_dev);
360 return IRQ_WAKE_THREAD;
361}
362EXPORT_SYMBOL(iio_pollfunc_store_time);
363
364struct iio_poll_func
365*iio_alloc_pollfunc(irqreturn_t (*h)(int irq, void *p),
366 irqreturn_t (*thread)(int irq, void *p),
367 int type,
368 struct iio_dev *indio_dev,
369 const char *fmt,
370 ...)
371{
372 va_list vargs;
373 struct iio_poll_func *pf;
374
375 pf = kmalloc(sizeof(*pf), GFP_KERNEL);
376 if (!pf)
377 return NULL;
378 va_start(vargs, fmt);
379 pf->name = kvasprintf(GFP_KERNEL, fmt, vargs);
380 va_end(vargs);
381 if (pf->name == NULL) {
382 kfree(pf);
383 return NULL;
384 }
385 pf->h = h;
386 pf->thread = thread;
387 pf->type = type;
388 pf->indio_dev = indio_dev;
389
390 return pf;
391}
392EXPORT_SYMBOL_GPL(iio_alloc_pollfunc);
393
394void iio_dealloc_pollfunc(struct iio_poll_func *pf)
395{
396 kfree(pf->name);
397 kfree(pf);
398}
399EXPORT_SYMBOL_GPL(iio_dealloc_pollfunc);
400
401/**
402 * current_trigger_show() - trigger consumer sysfs query current trigger
403 * @dev: device associated with an industrial I/O device
404 * @attr: pointer to the device_attribute structure that
405 * is being processed
406 * @buf: buffer where the current trigger name will be printed into
407 *
408 * For trigger consumers the current_trigger interface allows the trigger
409 * used by the device to be queried.
410 *
411 * Return: a negative number on failure, the number of characters written
412 * on success or 0 if no trigger is available
413 */
414static ssize_t current_trigger_show(struct device *dev,
415 struct device_attribute *attr, char *buf)
416{
417 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
418
419 if (indio_dev->trig)
420 return sysfs_emit(buf, "%s\n", indio_dev->trig->name);
421 return 0;
422}
423
424/**
425 * current_trigger_store() - trigger consumer sysfs set current trigger
426 * @dev: device associated with an industrial I/O device
427 * @attr: device attribute that is being processed
428 * @buf: string buffer that holds the name of the trigger
429 * @len: length of the trigger name held by buf
430 *
431 * For trigger consumers the current_trigger interface allows the trigger
432 * used for this device to be specified at run time based on the trigger's
433 * name.
434 *
435 * Return: negative error code on failure or length of the buffer
436 * on success
437 */
438static ssize_t current_trigger_store(struct device *dev,
439 struct device_attribute *attr,
440 const char *buf, size_t len)
441{
442 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
443 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
444 struct iio_trigger *oldtrig = indio_dev->trig;
445 struct iio_trigger *trig;
446 int ret;
447
448 scoped_guard(mutex, &iio_dev_opaque->mlock) {
449 if (iio_dev_opaque->currentmode == INDIO_BUFFER_TRIGGERED)
450 return -EBUSY;
451 if (iio_dev_opaque->trig_readonly)
452 return -EPERM;
453 }
454
455 trig = iio_trigger_acquire_by_name(buf);
456 if (oldtrig == trig) {
457 ret = len;
458 goto out_trigger_put;
459 }
460
461 if (trig && indio_dev->info->validate_trigger) {
462 ret = indio_dev->info->validate_trigger(indio_dev, trig);
463 if (ret)
464 goto out_trigger_put;
465 }
466
467 if (trig && trig->ops && trig->ops->validate_device) {
468 ret = trig->ops->validate_device(trig, indio_dev);
469 if (ret)
470 goto out_trigger_put;
471 }
472
473 indio_dev->trig = trig;
474
475 if (oldtrig) {
476 if (indio_dev->modes & INDIO_EVENT_TRIGGERED)
477 iio_trigger_detach_poll_func(oldtrig,
478 indio_dev->pollfunc_event);
479 iio_trigger_put(oldtrig);
480 }
481 if (indio_dev->trig) {
482 if (indio_dev->modes & INDIO_EVENT_TRIGGERED)
483 iio_trigger_attach_poll_func(indio_dev->trig,
484 indio_dev->pollfunc_event);
485 }
486
487 return len;
488
489out_trigger_put:
490 if (trig)
491 iio_trigger_put(trig);
492 return ret;
493}
494
495static DEVICE_ATTR_RW(current_trigger);
496
497static struct attribute *iio_trigger_consumer_attrs[] = {
498 &dev_attr_current_trigger.attr,
499 NULL,
500};
501
502static const struct attribute_group iio_trigger_consumer_attr_group = {
503 .name = "trigger",
504 .attrs = iio_trigger_consumer_attrs,
505};
506
507static void iio_trig_release(struct device *device)
508{
509 struct iio_trigger *trig = to_iio_trigger(device);
510 int i;
511
512 if (trig->subirq_base) {
513 for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
514 irq_modify_status(trig->subirq_base + i,
515 IRQ_NOAUTOEN,
516 IRQ_NOREQUEST | IRQ_NOPROBE);
517 irq_set_chip(trig->subirq_base + i,
518 NULL);
519 irq_set_handler(trig->subirq_base + i,
520 NULL);
521 }
522
523 irq_free_descs(trig->subirq_base,
524 CONFIG_IIO_CONSUMERS_PER_TRIGGER);
525 }
526 kfree(trig->name);
527 kfree(trig);
528}
529
530static const struct device_type iio_trig_type = {
531 .release = iio_trig_release,
532 .groups = iio_trig_dev_groups,
533};
534
535static void iio_trig_subirqmask(struct irq_data *d)
536{
537 struct irq_chip *chip = irq_data_get_irq_chip(d);
538 struct iio_trigger *trig = container_of(chip, struct iio_trigger, subirq_chip);
539
540 trig->subirqs[d->irq - trig->subirq_base].enabled = false;
541}
542
543static void iio_trig_subirqunmask(struct irq_data *d)
544{
545 struct irq_chip *chip = irq_data_get_irq_chip(d);
546 struct iio_trigger *trig = container_of(chip, struct iio_trigger, subirq_chip);
547
548 trig->subirqs[d->irq - trig->subirq_base].enabled = true;
549}
550
551static __printf(3, 0)
552struct iio_trigger *viio_trigger_alloc(struct device *parent,
553 struct module *this_mod,
554 const char *fmt,
555 va_list vargs)
556{
557 struct iio_trigger *trig;
558 int i;
559
560 trig = kzalloc(sizeof(*trig), GFP_KERNEL);
561 if (!trig)
562 return NULL;
563
564 trig->dev.parent = parent;
565 trig->dev.type = &iio_trig_type;
566 trig->dev.bus = &iio_bus_type;
567 device_initialize(&trig->dev);
568 INIT_WORK(&trig->reenable_work, iio_reenable_work_fn);
569
570 mutex_init(&trig->pool_lock);
571 trig->subirq_base = irq_alloc_descs(-1, 0,
572 CONFIG_IIO_CONSUMERS_PER_TRIGGER,
573 0);
574 if (trig->subirq_base < 0)
575 goto free_trig;
576
577 trig->name = kvasprintf(GFP_KERNEL, fmt, vargs);
578 if (trig->name == NULL)
579 goto free_descs;
580
581 INIT_LIST_HEAD(&trig->list);
582
583 trig->owner = this_mod;
584
585 trig->subirq_chip.name = trig->name;
586 trig->subirq_chip.irq_mask = &iio_trig_subirqmask;
587 trig->subirq_chip.irq_unmask = &iio_trig_subirqunmask;
588 for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
589 irq_set_chip(trig->subirq_base + i, &trig->subirq_chip);
590 irq_set_handler(trig->subirq_base + i, &handle_simple_irq);
591 irq_modify_status(trig->subirq_base + i,
592 IRQ_NOREQUEST | IRQ_NOAUTOEN, IRQ_NOPROBE);
593 }
594
595 return trig;
596
597free_descs:
598 irq_free_descs(trig->subirq_base, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
599free_trig:
600 kfree(trig);
601 return NULL;
602}
603
604/**
605 * __iio_trigger_alloc - Allocate a trigger
606 * @parent: Device to allocate iio_trigger for
607 * @this_mod: module allocating the trigger
608 * @fmt: trigger name format. If it includes format
609 * specifiers, the additional arguments following
610 * format are formatted and inserted in the resulting
611 * string replacing their respective specifiers.
612 * RETURNS:
613 * Pointer to allocated iio_trigger on success, NULL on failure.
614 */
615struct iio_trigger *__iio_trigger_alloc(struct device *parent,
616 struct module *this_mod,
617 const char *fmt, ...)
618{
619 struct iio_trigger *trig;
620 va_list vargs;
621
622 va_start(vargs, fmt);
623 trig = viio_trigger_alloc(parent, this_mod, fmt, vargs);
624 va_end(vargs);
625
626 return trig;
627}
628EXPORT_SYMBOL(__iio_trigger_alloc);
629
630void iio_trigger_free(struct iio_trigger *trig)
631{
632 if (trig)
633 put_device(&trig->dev);
634}
635EXPORT_SYMBOL(iio_trigger_free);
636
637static void devm_iio_trigger_release(struct device *dev, void *res)
638{
639 iio_trigger_free(*(struct iio_trigger **)res);
640}
641
642/**
643 * __devm_iio_trigger_alloc - Resource-managed iio_trigger_alloc()
644 * Managed iio_trigger_alloc. iio_trigger allocated with this function is
645 * automatically freed on driver detach.
646 * @parent: Device to allocate iio_trigger for
647 * @this_mod: module allocating the trigger
648 * @fmt: trigger name format. If it includes format
649 * specifiers, the additional arguments following
650 * format are formatted and inserted in the resulting
651 * string replacing their respective specifiers.
652 *
653 *
654 * RETURNS:
655 * Pointer to allocated iio_trigger on success, NULL on failure.
656 */
657struct iio_trigger *__devm_iio_trigger_alloc(struct device *parent,
658 struct module *this_mod,
659 const char *fmt, ...)
660{
661 struct iio_trigger **ptr, *trig;
662 va_list vargs;
663
664 ptr = devres_alloc(devm_iio_trigger_release, sizeof(*ptr),
665 GFP_KERNEL);
666 if (!ptr)
667 return NULL;
668
669 /* use raw alloc_dr for kmalloc caller tracing */
670 va_start(vargs, fmt);
671 trig = viio_trigger_alloc(parent, this_mod, fmt, vargs);
672 va_end(vargs);
673 if (trig) {
674 *ptr = trig;
675 devres_add(parent, ptr);
676 } else {
677 devres_free(ptr);
678 }
679
680 return trig;
681}
682EXPORT_SYMBOL_GPL(__devm_iio_trigger_alloc);
683
684static void devm_iio_trigger_unreg(void *trigger_info)
685{
686 iio_trigger_unregister(trigger_info);
687}
688
689/**
690 * devm_iio_trigger_register - Resource-managed iio_trigger_register()
691 * @dev: device this trigger was allocated for
692 * @trig_info: trigger to register
693 *
694 * Managed iio_trigger_register(). The IIO trigger registered with this
695 * function is automatically unregistered on driver detach. This function
696 * calls iio_trigger_register() internally. Refer to that function for more
697 * information.
698 *
699 * RETURNS:
700 * 0 on success, negative error number on failure.
701 */
702int devm_iio_trigger_register(struct device *dev,
703 struct iio_trigger *trig_info)
704{
705 int ret;
706
707 ret = iio_trigger_register(trig_info);
708 if (ret)
709 return ret;
710
711 return devm_add_action_or_reset(dev, devm_iio_trigger_unreg, trig_info);
712}
713EXPORT_SYMBOL_GPL(devm_iio_trigger_register);
714
715bool iio_trigger_using_own(struct iio_dev *indio_dev)
716{
717 return indio_dev->trig->attached_own_device;
718}
719EXPORT_SYMBOL(iio_trigger_using_own);
720
721/**
722 * iio_validate_own_trigger - Check if a trigger and IIO device belong to
723 * the same device
724 * @idev: the IIO device to check
725 * @trig: the IIO trigger to check
726 *
727 * This function can be used as the validate_trigger callback for triggers that
728 * can only be attached to their own device.
729 *
730 * Return: 0 if both the trigger and the IIO device belong to the same
731 * device, -EINVAL otherwise.
732 */
733int iio_validate_own_trigger(struct iio_dev *idev, struct iio_trigger *trig)
734{
735 if (idev->dev.parent != trig->dev.parent)
736 return -EINVAL;
737 return 0;
738}
739EXPORT_SYMBOL_GPL(iio_validate_own_trigger);
740
741/**
742 * iio_trigger_validate_own_device - Check if a trigger and IIO device belong to
743 * the same device
744 * @trig: The IIO trigger to check
745 * @indio_dev: the IIO device to check
746 *
747 * This function can be used as the validate_device callback for triggers that
748 * can only be attached to their own device.
749 *
750 * Return: 0 if both the trigger and the IIO device belong to the same
751 * device, -EINVAL otherwise.
752 */
753int iio_trigger_validate_own_device(struct iio_trigger *trig,
754 struct iio_dev *indio_dev)
755{
756 if (indio_dev->dev.parent != trig->dev.parent)
757 return -EINVAL;
758 return 0;
759}
760EXPORT_SYMBOL(iio_trigger_validate_own_device);
761
762int iio_device_register_trigger_consumer(struct iio_dev *indio_dev)
763{
764 return iio_device_register_sysfs_group(indio_dev,
765 &iio_trigger_consumer_attr_group);
766}
767
768void iio_device_unregister_trigger_consumer(struct iio_dev *indio_dev)
769{
770 /* Clean up an associated but not attached trigger reference */
771 if (indio_dev->trig)
772 iio_trigger_put(indio_dev->trig);
773}
774
775int iio_device_suspend_triggering(struct iio_dev *indio_dev)
776{
777 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
778
779 guard(mutex)(&iio_dev_opaque->mlock);
780
781 if ((indio_dev->pollfunc) && (indio_dev->pollfunc->irq > 0))
782 disable_irq(indio_dev->pollfunc->irq);
783
784 return 0;
785}
786EXPORT_SYMBOL(iio_device_suspend_triggering);
787
788int iio_device_resume_triggering(struct iio_dev *indio_dev)
789{
790 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
791
792 guard(mutex)(&iio_dev_opaque->mlock);
793
794 if ((indio_dev->pollfunc) && (indio_dev->pollfunc->irq > 0))
795 enable_irq(indio_dev->pollfunc->irq);
796
797 return 0;
798}
799EXPORT_SYMBOL(iio_device_resume_triggering);
1/* The industrial I/O core, trigger handling functions
2 *
3 * Copyright (c) 2008 Jonathan Cameron
4 *
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 as published by
7 * the Free Software Foundation.
8 */
9
10#include <linux/kernel.h>
11#include <linux/idr.h>
12#include <linux/err.h>
13#include <linux/device.h>
14#include <linux/interrupt.h>
15#include <linux/list.h>
16#include <linux/slab.h>
17
18#include <linux/iio/iio.h>
19#include <linux/iio/trigger.h>
20#include "iio_core.h"
21#include "iio_core_trigger.h"
22#include <linux/iio/trigger_consumer.h>
23
24/* RFC - Question of approach
25 * Make the common case (single sensor single trigger)
26 * simple by starting trigger capture from when first sensors
27 * is added.
28 *
29 * Complex simultaneous start requires use of 'hold' functionality
30 * of the trigger. (not implemented)
31 *
32 * Any other suggestions?
33 */
34
35static DEFINE_IDA(iio_trigger_ida);
36
37/* Single list of all available triggers */
38static LIST_HEAD(iio_trigger_list);
39static DEFINE_MUTEX(iio_trigger_list_lock);
40
41/**
42 * iio_trigger_read_name() - retrieve useful identifying name
43 **/
44static ssize_t iio_trigger_read_name(struct device *dev,
45 struct device_attribute *attr,
46 char *buf)
47{
48 struct iio_trigger *trig = to_iio_trigger(dev);
49 return sprintf(buf, "%s\n", trig->name);
50}
51
52static DEVICE_ATTR(name, S_IRUGO, iio_trigger_read_name, NULL);
53
54static struct attribute *iio_trig_dev_attrs[] = {
55 &dev_attr_name.attr,
56 NULL,
57};
58ATTRIBUTE_GROUPS(iio_trig_dev);
59
60int iio_trigger_register(struct iio_trigger *trig_info)
61{
62 int ret;
63
64 trig_info->id = ida_simple_get(&iio_trigger_ida, 0, 0, GFP_KERNEL);
65 if (trig_info->id < 0)
66 return trig_info->id;
67
68 /* Set the name used for the sysfs directory etc */
69 dev_set_name(&trig_info->dev, "trigger%ld",
70 (unsigned long) trig_info->id);
71
72 ret = device_add(&trig_info->dev);
73 if (ret)
74 goto error_unregister_id;
75
76 /* Add to list of available triggers held by the IIO core */
77 mutex_lock(&iio_trigger_list_lock);
78 list_add_tail(&trig_info->list, &iio_trigger_list);
79 mutex_unlock(&iio_trigger_list_lock);
80
81 return 0;
82
83error_unregister_id:
84 ida_simple_remove(&iio_trigger_ida, trig_info->id);
85 return ret;
86}
87EXPORT_SYMBOL(iio_trigger_register);
88
89void iio_trigger_unregister(struct iio_trigger *trig_info)
90{
91 mutex_lock(&iio_trigger_list_lock);
92 list_del(&trig_info->list);
93 mutex_unlock(&iio_trigger_list_lock);
94
95 ida_simple_remove(&iio_trigger_ida, trig_info->id);
96 /* Possible issue in here */
97 device_del(&trig_info->dev);
98}
99EXPORT_SYMBOL(iio_trigger_unregister);
100
101static struct iio_trigger *iio_trigger_find_by_name(const char *name,
102 size_t len)
103{
104 struct iio_trigger *trig = NULL, *iter;
105
106 mutex_lock(&iio_trigger_list_lock);
107 list_for_each_entry(iter, &iio_trigger_list, list)
108 if (sysfs_streq(iter->name, name)) {
109 trig = iter;
110 break;
111 }
112 mutex_unlock(&iio_trigger_list_lock);
113
114 return trig;
115}
116
117void iio_trigger_poll(struct iio_trigger *trig, s64 time)
118{
119 int i;
120
121 if (!atomic_read(&trig->use_count)) {
122 atomic_set(&trig->use_count, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
123
124 for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
125 if (trig->subirqs[i].enabled)
126 generic_handle_irq(trig->subirq_base + i);
127 else
128 iio_trigger_notify_done(trig);
129 }
130 }
131}
132EXPORT_SYMBOL(iio_trigger_poll);
133
134irqreturn_t iio_trigger_generic_data_rdy_poll(int irq, void *private)
135{
136 iio_trigger_poll(private, iio_get_time_ns());
137 return IRQ_HANDLED;
138}
139EXPORT_SYMBOL(iio_trigger_generic_data_rdy_poll);
140
141void iio_trigger_poll_chained(struct iio_trigger *trig, s64 time)
142{
143 int i;
144
145 if (!atomic_read(&trig->use_count)) {
146 atomic_set(&trig->use_count, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
147
148 for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
149 if (trig->subirqs[i].enabled)
150 handle_nested_irq(trig->subirq_base + i);
151 else
152 iio_trigger_notify_done(trig);
153 }
154 }
155}
156EXPORT_SYMBOL(iio_trigger_poll_chained);
157
158void iio_trigger_notify_done(struct iio_trigger *trig)
159{
160 if (atomic_dec_and_test(&trig->use_count) && trig->ops &&
161 trig->ops->try_reenable)
162 if (trig->ops->try_reenable(trig))
163 /* Missed an interrupt so launch new poll now */
164 iio_trigger_poll(trig, 0);
165}
166EXPORT_SYMBOL(iio_trigger_notify_done);
167
168/* Trigger Consumer related functions */
169static int iio_trigger_get_irq(struct iio_trigger *trig)
170{
171 int ret;
172 mutex_lock(&trig->pool_lock);
173 ret = bitmap_find_free_region(trig->pool,
174 CONFIG_IIO_CONSUMERS_PER_TRIGGER,
175 ilog2(1));
176 mutex_unlock(&trig->pool_lock);
177 if (ret >= 0)
178 ret += trig->subirq_base;
179
180 return ret;
181}
182
183static void iio_trigger_put_irq(struct iio_trigger *trig, int irq)
184{
185 mutex_lock(&trig->pool_lock);
186 clear_bit(irq - trig->subirq_base, trig->pool);
187 mutex_unlock(&trig->pool_lock);
188}
189
190/* Complexity in here. With certain triggers (datardy) an acknowledgement
191 * may be needed if the pollfuncs do not include the data read for the
192 * triggering device.
193 * This is not currently handled. Alternative of not enabling trigger unless
194 * the relevant function is in there may be the best option.
195 */
196/* Worth protecting against double additions? */
197static int iio_trigger_attach_poll_func(struct iio_trigger *trig,
198 struct iio_poll_func *pf)
199{
200 int ret = 0;
201 bool notinuse
202 = bitmap_empty(trig->pool, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
203
204 /* Prevent the module from being removed whilst attached to a trigger */
205 __module_get(pf->indio_dev->info->driver_module);
206 pf->irq = iio_trigger_get_irq(trig);
207 ret = request_threaded_irq(pf->irq, pf->h, pf->thread,
208 pf->type, pf->name,
209 pf);
210 if (ret < 0) {
211 module_put(pf->indio_dev->info->driver_module);
212 return ret;
213 }
214
215 if (trig->ops && trig->ops->set_trigger_state && notinuse) {
216 ret = trig->ops->set_trigger_state(trig, true);
217 if (ret < 0)
218 module_put(pf->indio_dev->info->driver_module);
219 }
220
221 return ret;
222}
223
224static int iio_trigger_detach_poll_func(struct iio_trigger *trig,
225 struct iio_poll_func *pf)
226{
227 int ret = 0;
228 bool no_other_users
229 = (bitmap_weight(trig->pool,
230 CONFIG_IIO_CONSUMERS_PER_TRIGGER)
231 == 1);
232 if (trig->ops && trig->ops->set_trigger_state && no_other_users) {
233 ret = trig->ops->set_trigger_state(trig, false);
234 if (ret)
235 return ret;
236 }
237 iio_trigger_put_irq(trig, pf->irq);
238 free_irq(pf->irq, pf);
239 module_put(pf->indio_dev->info->driver_module);
240
241 return ret;
242}
243
244irqreturn_t iio_pollfunc_store_time(int irq, void *p)
245{
246 struct iio_poll_func *pf = p;
247 pf->timestamp = iio_get_time_ns();
248 return IRQ_WAKE_THREAD;
249}
250EXPORT_SYMBOL(iio_pollfunc_store_time);
251
252struct iio_poll_func
253*iio_alloc_pollfunc(irqreturn_t (*h)(int irq, void *p),
254 irqreturn_t (*thread)(int irq, void *p),
255 int type,
256 struct iio_dev *indio_dev,
257 const char *fmt,
258 ...)
259{
260 va_list vargs;
261 struct iio_poll_func *pf;
262
263 pf = kmalloc(sizeof *pf, GFP_KERNEL);
264 if (pf == NULL)
265 return NULL;
266 va_start(vargs, fmt);
267 pf->name = kvasprintf(GFP_KERNEL, fmt, vargs);
268 va_end(vargs);
269 if (pf->name == NULL) {
270 kfree(pf);
271 return NULL;
272 }
273 pf->h = h;
274 pf->thread = thread;
275 pf->type = type;
276 pf->indio_dev = indio_dev;
277
278 return pf;
279}
280EXPORT_SYMBOL_GPL(iio_alloc_pollfunc);
281
282void iio_dealloc_pollfunc(struct iio_poll_func *pf)
283{
284 kfree(pf->name);
285 kfree(pf);
286}
287EXPORT_SYMBOL_GPL(iio_dealloc_pollfunc);
288
289/**
290 * iio_trigger_read_current() - trigger consumer sysfs query current trigger
291 *
292 * For trigger consumers the current_trigger interface allows the trigger
293 * used by the device to be queried.
294 **/
295static ssize_t iio_trigger_read_current(struct device *dev,
296 struct device_attribute *attr,
297 char *buf)
298{
299 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
300
301 if (indio_dev->trig)
302 return sprintf(buf, "%s\n", indio_dev->trig->name);
303 return 0;
304}
305
306/**
307 * iio_trigger_write_current() - trigger consumer sysfs set current trigger
308 *
309 * For trigger consumers the current_trigger interface allows the trigger
310 * used for this device to be specified at run time based on the trigger's
311 * name.
312 **/
313static ssize_t iio_trigger_write_current(struct device *dev,
314 struct device_attribute *attr,
315 const char *buf,
316 size_t len)
317{
318 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
319 struct iio_trigger *oldtrig = indio_dev->trig;
320 struct iio_trigger *trig;
321 int ret;
322
323 mutex_lock(&indio_dev->mlock);
324 if (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED) {
325 mutex_unlock(&indio_dev->mlock);
326 return -EBUSY;
327 }
328 mutex_unlock(&indio_dev->mlock);
329
330 trig = iio_trigger_find_by_name(buf, len);
331 if (oldtrig == trig)
332 return len;
333
334 if (trig && indio_dev->info->validate_trigger) {
335 ret = indio_dev->info->validate_trigger(indio_dev, trig);
336 if (ret)
337 return ret;
338 }
339
340 if (trig && trig->ops && trig->ops->validate_device) {
341 ret = trig->ops->validate_device(trig, indio_dev);
342 if (ret)
343 return ret;
344 }
345
346 indio_dev->trig = trig;
347
348 if (oldtrig)
349 iio_trigger_put(oldtrig);
350 if (indio_dev->trig)
351 iio_trigger_get(indio_dev->trig);
352
353 return len;
354}
355
356static DEVICE_ATTR(current_trigger, S_IRUGO | S_IWUSR,
357 iio_trigger_read_current,
358 iio_trigger_write_current);
359
360static struct attribute *iio_trigger_consumer_attrs[] = {
361 &dev_attr_current_trigger.attr,
362 NULL,
363};
364
365static const struct attribute_group iio_trigger_consumer_attr_group = {
366 .name = "trigger",
367 .attrs = iio_trigger_consumer_attrs,
368};
369
370static void iio_trig_release(struct device *device)
371{
372 struct iio_trigger *trig = to_iio_trigger(device);
373 int i;
374
375 if (trig->subirq_base) {
376 for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
377 irq_modify_status(trig->subirq_base + i,
378 IRQ_NOAUTOEN,
379 IRQ_NOREQUEST | IRQ_NOPROBE);
380 irq_set_chip(trig->subirq_base + i,
381 NULL);
382 irq_set_handler(trig->subirq_base + i,
383 NULL);
384 }
385
386 irq_free_descs(trig->subirq_base,
387 CONFIG_IIO_CONSUMERS_PER_TRIGGER);
388 }
389 kfree(trig->name);
390 kfree(trig);
391}
392
393static struct device_type iio_trig_type = {
394 .release = iio_trig_release,
395 .groups = iio_trig_dev_groups,
396};
397
398static void iio_trig_subirqmask(struct irq_data *d)
399{
400 struct irq_chip *chip = irq_data_get_irq_chip(d);
401 struct iio_trigger *trig
402 = container_of(chip,
403 struct iio_trigger, subirq_chip);
404 trig->subirqs[d->irq - trig->subirq_base].enabled = false;
405}
406
407static void iio_trig_subirqunmask(struct irq_data *d)
408{
409 struct irq_chip *chip = irq_data_get_irq_chip(d);
410 struct iio_trigger *trig
411 = container_of(chip,
412 struct iio_trigger, subirq_chip);
413 trig->subirqs[d->irq - trig->subirq_base].enabled = true;
414}
415
416static struct iio_trigger *viio_trigger_alloc(const char *fmt, va_list vargs)
417{
418 struct iio_trigger *trig;
419 trig = kzalloc(sizeof *trig, GFP_KERNEL);
420 if (trig) {
421 int i;
422 trig->dev.type = &iio_trig_type;
423 trig->dev.bus = &iio_bus_type;
424 device_initialize(&trig->dev);
425
426 mutex_init(&trig->pool_lock);
427 trig->subirq_base
428 = irq_alloc_descs(-1, 0,
429 CONFIG_IIO_CONSUMERS_PER_TRIGGER,
430 0);
431 if (trig->subirq_base < 0) {
432 kfree(trig);
433 return NULL;
434 }
435
436 trig->name = kvasprintf(GFP_KERNEL, fmt, vargs);
437 if (trig->name == NULL) {
438 irq_free_descs(trig->subirq_base,
439 CONFIG_IIO_CONSUMERS_PER_TRIGGER);
440 kfree(trig);
441 return NULL;
442 }
443 trig->subirq_chip.name = trig->name;
444 trig->subirq_chip.irq_mask = &iio_trig_subirqmask;
445 trig->subirq_chip.irq_unmask = &iio_trig_subirqunmask;
446 for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
447 irq_set_chip(trig->subirq_base + i,
448 &trig->subirq_chip);
449 irq_set_handler(trig->subirq_base + i,
450 &handle_simple_irq);
451 irq_modify_status(trig->subirq_base + i,
452 IRQ_NOREQUEST | IRQ_NOAUTOEN,
453 IRQ_NOPROBE);
454 }
455 get_device(&trig->dev);
456 }
457
458 return trig;
459}
460
461struct iio_trigger *iio_trigger_alloc(const char *fmt, ...)
462{
463 struct iio_trigger *trig;
464 va_list vargs;
465
466 va_start(vargs, fmt);
467 trig = viio_trigger_alloc(fmt, vargs);
468 va_end(vargs);
469
470 return trig;
471}
472EXPORT_SYMBOL(iio_trigger_alloc);
473
474void iio_trigger_free(struct iio_trigger *trig)
475{
476 if (trig)
477 put_device(&trig->dev);
478}
479EXPORT_SYMBOL(iio_trigger_free);
480
481static void devm_iio_trigger_release(struct device *dev, void *res)
482{
483 iio_trigger_free(*(struct iio_trigger **)res);
484}
485
486static int devm_iio_trigger_match(struct device *dev, void *res, void *data)
487{
488 struct iio_trigger **r = res;
489
490 if (!r || !*r) {
491 WARN_ON(!r || !*r);
492 return 0;
493 }
494
495 return *r == data;
496}
497
498/**
499 * devm_iio_trigger_alloc - Resource-managed iio_trigger_alloc()
500 * @dev: Device to allocate iio_trigger for
501 * @fmt: trigger name format. If it includes format
502 * specifiers, the additional arguments following
503 * format are formatted and inserted in the resulting
504 * string replacing their respective specifiers.
505 *
506 * Managed iio_trigger_alloc. iio_trigger allocated with this function is
507 * automatically freed on driver detach.
508 *
509 * If an iio_trigger allocated with this function needs to be freed separately,
510 * devm_iio_trigger_free() must be used.
511 *
512 * RETURNS:
513 * Pointer to allocated iio_trigger on success, NULL on failure.
514 */
515struct iio_trigger *devm_iio_trigger_alloc(struct device *dev,
516 const char *fmt, ...)
517{
518 struct iio_trigger **ptr, *trig;
519 va_list vargs;
520
521 ptr = devres_alloc(devm_iio_trigger_release, sizeof(*ptr),
522 GFP_KERNEL);
523 if (!ptr)
524 return NULL;
525
526 /* use raw alloc_dr for kmalloc caller tracing */
527 va_start(vargs, fmt);
528 trig = viio_trigger_alloc(fmt, vargs);
529 va_end(vargs);
530 if (trig) {
531 *ptr = trig;
532 devres_add(dev, ptr);
533 } else {
534 devres_free(ptr);
535 }
536
537 return trig;
538}
539EXPORT_SYMBOL_GPL(devm_iio_trigger_alloc);
540
541/**
542 * devm_iio_trigger_free - Resource-managed iio_trigger_free()
543 * @dev: Device this iio_dev belongs to
544 * @iio_trig: the iio_trigger associated with the device
545 *
546 * Free iio_trigger allocated with devm_iio_trigger_alloc().
547 */
548void devm_iio_trigger_free(struct device *dev, struct iio_trigger *iio_trig)
549{
550 int rc;
551
552 rc = devres_release(dev, devm_iio_trigger_release,
553 devm_iio_trigger_match, iio_trig);
554 WARN_ON(rc);
555}
556EXPORT_SYMBOL_GPL(devm_iio_trigger_free);
557
558void iio_device_register_trigger_consumer(struct iio_dev *indio_dev)
559{
560 indio_dev->groups[indio_dev->groupcounter++] =
561 &iio_trigger_consumer_attr_group;
562}
563
564void iio_device_unregister_trigger_consumer(struct iio_dev *indio_dev)
565{
566 /* Clean up an associated but not attached trigger reference */
567 if (indio_dev->trig)
568 iio_trigger_put(indio_dev->trig);
569}
570
571int iio_triggered_buffer_postenable(struct iio_dev *indio_dev)
572{
573 return iio_trigger_attach_poll_func(indio_dev->trig,
574 indio_dev->pollfunc);
575}
576EXPORT_SYMBOL(iio_triggered_buffer_postenable);
577
578int iio_triggered_buffer_predisable(struct iio_dev *indio_dev)
579{
580 return iio_trigger_detach_poll_func(indio_dev->trig,
581 indio_dev->pollfunc);
582}
583EXPORT_SYMBOL(iio_triggered_buffer_predisable);