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