1 // SPDX-License-Identifier: GPL-2.0-only
2 /* The industrial I/O core, trigger handling functions
4 * Copyright (c) 2008 Jonathan Cameron
7 #include <linux/kernel.h>
10 #include <linux/device.h>
11 #include <linux/interrupt.h>
12 #include <linux/list.h>
13 #include <linux/slab.h>
15 #include <linux/iio/iio.h>
16 #include <linux/iio/iio-opaque.h>
17 #include <linux/iio/trigger.h>
19 #include "iio_core_trigger.h"
20 #include <linux/iio/trigger_consumer.h>
22 /* RFC - Question of approach
23 * Make the common case (single sensor single trigger)
24 * simple by starting trigger capture from when first sensors
27 * Complex simultaneous start requires use of 'hold' functionality
28 * of the trigger. (not implemented)
30 * Any other suggestions?
33 static DEFINE_IDA(iio_trigger_ida);
35 /* Single list of all available triggers */
36 static LIST_HEAD(iio_trigger_list);
37 static DEFINE_MUTEX(iio_trigger_list_lock);
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
44 * @buf: buffer to print the name into
46 * Return: a negative number on failure or the number of written
47 * characters on success.
49 static ssize_t name_show(struct device *dev, struct device_attribute *attr,
52 struct iio_trigger *trig = to_iio_trigger(dev);
54 return sysfs_emit(buf, "%s\n", trig->name);
57 static DEVICE_ATTR_RO(name);
59 static struct attribute *iio_trig_dev_attrs[] = {
63 ATTRIBUTE_GROUPS(iio_trig_dev);
65 static struct iio_trigger *__iio_trigger_find_by_name(const char *name);
67 int iio_trigger_register(struct iio_trigger *trig_info)
71 trig_info->id = ida_alloc(&iio_trigger_ida, GFP_KERNEL);
72 if (trig_info->id < 0)
75 /* Set the name used for the sysfs directory etc */
76 dev_set_name(&trig_info->dev, "trigger%d", trig_info->id);
78 ret = device_add(&trig_info->dev);
80 goto error_unregister_id;
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);
87 goto error_device_del;
89 list_add_tail(&trig_info->list, &iio_trigger_list);
90 mutex_unlock(&iio_trigger_list_lock);
95 mutex_unlock(&iio_trigger_list_lock);
96 device_del(&trig_info->dev);
98 ida_free(&iio_trigger_ida, trig_info->id);
101 EXPORT_SYMBOL(iio_trigger_register);
103 void iio_trigger_unregister(struct iio_trigger *trig_info)
105 mutex_lock(&iio_trigger_list_lock);
106 list_del(&trig_info->list);
107 mutex_unlock(&iio_trigger_list_lock);
109 ida_free(&iio_trigger_ida, trig_info->id);
110 /* Possible issue in here */
111 device_del(&trig_info->dev);
113 EXPORT_SYMBOL(iio_trigger_unregister);
115 int iio_trigger_set_immutable(struct iio_dev *indio_dev, struct iio_trigger *trig)
117 struct iio_dev_opaque *iio_dev_opaque;
119 if (!indio_dev || !trig)
122 iio_dev_opaque = to_iio_dev_opaque(indio_dev);
123 mutex_lock(&indio_dev->mlock);
124 WARN_ON(iio_dev_opaque->trig_readonly);
126 indio_dev->trig = iio_trigger_get(trig);
127 iio_dev_opaque->trig_readonly = true;
128 mutex_unlock(&indio_dev->mlock);
132 EXPORT_SYMBOL(iio_trigger_set_immutable);
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)
137 struct iio_trigger *iter;
139 list_for_each_entry(iter, &iio_trigger_list, list)
140 if (!strcmp(iter->name, name))
146 static struct iio_trigger *iio_trigger_acquire_by_name(const char *name)
148 struct iio_trigger *trig = NULL, *iter;
150 mutex_lock(&iio_trigger_list_lock);
151 list_for_each_entry(iter, &iio_trigger_list, list)
152 if (sysfs_streq(iter->name, name)) {
154 iio_trigger_get(trig);
157 mutex_unlock(&iio_trigger_list_lock);
162 static void iio_reenable_work_fn(struct work_struct *work)
164 struct iio_trigger *trig = container_of(work, struct iio_trigger,
168 * This 'might' occur after the trigger state is set to disabled -
169 * in that case the driver should skip reenabling.
171 trig->ops->reenable(trig);
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.
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.
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.
188 static void iio_trigger_notify_done_atomic(struct iio_trigger *trig)
190 if (atomic_dec_and_test(&trig->use_count) && trig->ops &&
192 schedule_work(&trig->reenable_work);
195 void iio_trigger_poll(struct iio_trigger *trig)
199 if (!atomic_read(&trig->use_count)) {
200 atomic_set(&trig->use_count, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
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);
206 iio_trigger_notify_done_atomic(trig);
210 EXPORT_SYMBOL(iio_trigger_poll);
212 irqreturn_t iio_trigger_generic_data_rdy_poll(int irq, void *private)
214 iio_trigger_poll(private);
217 EXPORT_SYMBOL(iio_trigger_generic_data_rdy_poll);
219 void iio_trigger_poll_chained(struct iio_trigger *trig)
223 if (!atomic_read(&trig->use_count)) {
224 atomic_set(&trig->use_count, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
226 for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
227 if (trig->subirqs[i].enabled)
228 handle_nested_irq(trig->subirq_base + i);
230 iio_trigger_notify_done(trig);
234 EXPORT_SYMBOL(iio_trigger_poll_chained);
236 void iio_trigger_notify_done(struct iio_trigger *trig)
238 if (atomic_dec_and_test(&trig->use_count) && trig->ops &&
240 trig->ops->reenable(trig);
242 EXPORT_SYMBOL(iio_trigger_notify_done);
244 /* Trigger Consumer related functions */
245 static int iio_trigger_get_irq(struct iio_trigger *trig)
249 mutex_lock(&trig->pool_lock);
250 ret = bitmap_find_free_region(trig->pool,
251 CONFIG_IIO_CONSUMERS_PER_TRIGGER,
253 mutex_unlock(&trig->pool_lock);
255 ret += trig->subirq_base;
260 static void iio_trigger_put_irq(struct iio_trigger *trig, int irq)
262 mutex_lock(&trig->pool_lock);
263 clear_bit(irq - trig->subirq_base, trig->pool);
264 mutex_unlock(&trig->pool_lock);
267 /* Complexity in here. With certain triggers (datardy) an acknowledgement
268 * may be needed if the pollfuncs do not include the data read for the
270 * This is not currently handled. Alternative of not enabling trigger unless
271 * the relevant function is in there may be the best option.
273 /* Worth protecting against double additions? */
274 int iio_trigger_attach_poll_func(struct iio_trigger *trig,
275 struct iio_poll_func *pf)
277 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(pf->indio_dev);
279 bitmap_empty(trig->pool, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
282 /* Prevent the module from being removed whilst attached to a trigger */
283 __module_get(iio_dev_opaque->driver_module);
286 pf->irq = iio_trigger_get_irq(trig);
288 pr_err("Could not find an available irq for trigger %s, CONFIG_IIO_CONSUMERS_PER_TRIGGER=%d limit might be exceeded\n",
289 trig->name, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
294 ret = request_threaded_irq(pf->irq, pf->h, pf->thread,
300 /* Enable trigger in driver */
301 if (trig->ops && trig->ops->set_trigger_state && notinuse) {
302 ret = trig->ops->set_trigger_state(trig, true);
308 * Check if we just registered to our own trigger: we determine that
309 * this is the case if the IIO device and the trigger device share the
310 * same parent device.
312 if (pf->indio_dev->dev.parent == trig->dev.parent)
313 trig->attached_own_device = true;
318 free_irq(pf->irq, pf);
320 iio_trigger_put_irq(trig, pf->irq);
322 module_put(iio_dev_opaque->driver_module);
326 int iio_trigger_detach_poll_func(struct iio_trigger *trig,
327 struct iio_poll_func *pf)
329 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(pf->indio_dev);
330 bool no_other_users =
331 bitmap_weight(trig->pool, CONFIG_IIO_CONSUMERS_PER_TRIGGER) == 1;
334 if (trig->ops && trig->ops->set_trigger_state && no_other_users) {
335 ret = trig->ops->set_trigger_state(trig, false);
339 if (pf->indio_dev->dev.parent == trig->dev.parent)
340 trig->attached_own_device = false;
341 iio_trigger_put_irq(trig, pf->irq);
342 free_irq(pf->irq, pf);
343 module_put(iio_dev_opaque->driver_module);
348 irqreturn_t iio_pollfunc_store_time(int irq, void *p)
350 struct iio_poll_func *pf = p;
352 pf->timestamp = iio_get_time_ns(pf->indio_dev);
353 return IRQ_WAKE_THREAD;
355 EXPORT_SYMBOL(iio_pollfunc_store_time);
358 *iio_alloc_pollfunc(irqreturn_t (*h)(int irq, void *p),
359 irqreturn_t (*thread)(int irq, void *p),
361 struct iio_dev *indio_dev,
366 struct iio_poll_func *pf;
368 pf = kmalloc(sizeof(*pf), GFP_KERNEL);
371 va_start(vargs, fmt);
372 pf->name = kvasprintf(GFP_KERNEL, fmt, vargs);
374 if (pf->name == NULL) {
381 pf->indio_dev = indio_dev;
385 EXPORT_SYMBOL_GPL(iio_alloc_pollfunc);
387 void iio_dealloc_pollfunc(struct iio_poll_func *pf)
392 EXPORT_SYMBOL_GPL(iio_dealloc_pollfunc);
395 * current_trigger_show() - trigger consumer sysfs query current trigger
396 * @dev: device associated with an industrial I/O device
397 * @attr: pointer to the device_attribute structure that
399 * @buf: buffer where the current trigger name will be printed into
401 * For trigger consumers the current_trigger interface allows the trigger
402 * used by the device to be queried.
404 * Return: a negative number on failure, the number of characters written
405 * on success or 0 if no trigger is available
407 static ssize_t current_trigger_show(struct device *dev,
408 struct device_attribute *attr, char *buf)
410 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
413 return sysfs_emit(buf, "%s\n", indio_dev->trig->name);
418 * current_trigger_store() - trigger consumer sysfs set current trigger
419 * @dev: device associated with an industrial I/O device
420 * @attr: device attribute that is being processed
421 * @buf: string buffer that holds the name of the trigger
422 * @len: length of the trigger name held by buf
424 * For trigger consumers the current_trigger interface allows the trigger
425 * used for this device to be specified at run time based on the trigger's
428 * Return: negative error code on failure or length of the buffer
431 static ssize_t current_trigger_store(struct device *dev,
432 struct device_attribute *attr,
433 const char *buf, size_t len)
435 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
436 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
437 struct iio_trigger *oldtrig = indio_dev->trig;
438 struct iio_trigger *trig;
441 mutex_lock(&indio_dev->mlock);
442 if (iio_dev_opaque->currentmode == INDIO_BUFFER_TRIGGERED) {
443 mutex_unlock(&indio_dev->mlock);
446 if (iio_dev_opaque->trig_readonly) {
447 mutex_unlock(&indio_dev->mlock);
450 mutex_unlock(&indio_dev->mlock);
452 trig = iio_trigger_acquire_by_name(buf);
453 if (oldtrig == trig) {
455 goto out_trigger_put;
458 if (trig && indio_dev->info->validate_trigger) {
459 ret = indio_dev->info->validate_trigger(indio_dev, trig);
461 goto out_trigger_put;
464 if (trig && trig->ops && trig->ops->validate_device) {
465 ret = trig->ops->validate_device(trig, indio_dev);
467 goto out_trigger_put;
470 indio_dev->trig = trig;
473 if (indio_dev->modes & INDIO_EVENT_TRIGGERED)
474 iio_trigger_detach_poll_func(oldtrig,
475 indio_dev->pollfunc_event);
476 iio_trigger_put(oldtrig);
478 if (indio_dev->trig) {
479 if (indio_dev->modes & INDIO_EVENT_TRIGGERED)
480 iio_trigger_attach_poll_func(indio_dev->trig,
481 indio_dev->pollfunc_event);
488 iio_trigger_put(trig);
492 static DEVICE_ATTR_RW(current_trigger);
494 static struct attribute *iio_trigger_consumer_attrs[] = {
495 &dev_attr_current_trigger.attr,
499 static const struct attribute_group iio_trigger_consumer_attr_group = {
501 .attrs = iio_trigger_consumer_attrs,
504 static void iio_trig_release(struct device *device)
506 struct iio_trigger *trig = to_iio_trigger(device);
509 if (trig->subirq_base) {
510 for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
511 irq_modify_status(trig->subirq_base + i,
513 IRQ_NOREQUEST | IRQ_NOPROBE);
514 irq_set_chip(trig->subirq_base + i,
516 irq_set_handler(trig->subirq_base + i,
520 irq_free_descs(trig->subirq_base,
521 CONFIG_IIO_CONSUMERS_PER_TRIGGER);
527 static const struct device_type iio_trig_type = {
528 .release = iio_trig_release,
529 .groups = iio_trig_dev_groups,
532 static void iio_trig_subirqmask(struct irq_data *d)
534 struct irq_chip *chip = irq_data_get_irq_chip(d);
535 struct iio_trigger *trig = container_of(chip, struct iio_trigger, subirq_chip);
537 trig->subirqs[d->irq - trig->subirq_base].enabled = false;
540 static void iio_trig_subirqunmask(struct irq_data *d)
542 struct irq_chip *chip = irq_data_get_irq_chip(d);
543 struct iio_trigger *trig = container_of(chip, struct iio_trigger, subirq_chip);
545 trig->subirqs[d->irq - trig->subirq_base].enabled = true;
548 static __printf(3, 0)
549 struct iio_trigger *viio_trigger_alloc(struct device *parent,
550 struct module *this_mod,
554 struct iio_trigger *trig;
557 trig = kzalloc(sizeof(*trig), GFP_KERNEL);
561 trig->dev.parent = parent;
562 trig->dev.type = &iio_trig_type;
563 trig->dev.bus = &iio_bus_type;
564 device_initialize(&trig->dev);
565 INIT_WORK(&trig->reenable_work, iio_reenable_work_fn);
567 mutex_init(&trig->pool_lock);
568 trig->subirq_base = irq_alloc_descs(-1, 0,
569 CONFIG_IIO_CONSUMERS_PER_TRIGGER,
571 if (trig->subirq_base < 0)
574 trig->name = kvasprintf(GFP_KERNEL, fmt, vargs);
575 if (trig->name == NULL)
578 INIT_LIST_HEAD(&trig->list);
580 trig->owner = this_mod;
582 trig->subirq_chip.name = trig->name;
583 trig->subirq_chip.irq_mask = &iio_trig_subirqmask;
584 trig->subirq_chip.irq_unmask = &iio_trig_subirqunmask;
585 for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
586 irq_set_chip(trig->subirq_base + i, &trig->subirq_chip);
587 irq_set_handler(trig->subirq_base + i, &handle_simple_irq);
588 irq_modify_status(trig->subirq_base + i,
589 IRQ_NOREQUEST | IRQ_NOAUTOEN, IRQ_NOPROBE);
595 irq_free_descs(trig->subirq_base, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
602 * __iio_trigger_alloc - Allocate a trigger
603 * @parent: Device to allocate iio_trigger for
604 * @this_mod: module allocating the trigger
605 * @fmt: trigger name format. If it includes format
606 * specifiers, the additional arguments following
607 * format are formatted and inserted in the resulting
608 * string replacing their respective specifiers.
610 * Pointer to allocated iio_trigger on success, NULL on failure.
612 struct iio_trigger *__iio_trigger_alloc(struct device *parent,
613 struct module *this_mod,
614 const char *fmt, ...)
616 struct iio_trigger *trig;
619 va_start(vargs, fmt);
620 trig = viio_trigger_alloc(parent, this_mod, fmt, vargs);
625 EXPORT_SYMBOL(__iio_trigger_alloc);
627 void iio_trigger_free(struct iio_trigger *trig)
630 put_device(&trig->dev);
632 EXPORT_SYMBOL(iio_trigger_free);
634 static void devm_iio_trigger_release(struct device *dev, void *res)
636 iio_trigger_free(*(struct iio_trigger **)res);
640 * __devm_iio_trigger_alloc - Resource-managed iio_trigger_alloc()
641 * Managed iio_trigger_alloc. iio_trigger allocated with this function is
642 * automatically freed on driver detach.
643 * @parent: Device to allocate iio_trigger for
644 * @this_mod: module allocating the trigger
645 * @fmt: trigger name format. If it includes format
646 * specifiers, the additional arguments following
647 * format are formatted and inserted in the resulting
648 * string replacing their respective specifiers.
652 * Pointer to allocated iio_trigger on success, NULL on failure.
654 struct iio_trigger *__devm_iio_trigger_alloc(struct device *parent,
655 struct module *this_mod,
656 const char *fmt, ...)
658 struct iio_trigger **ptr, *trig;
661 ptr = devres_alloc(devm_iio_trigger_release, sizeof(*ptr),
666 /* use raw alloc_dr for kmalloc caller tracing */
667 va_start(vargs, fmt);
668 trig = viio_trigger_alloc(parent, this_mod, fmt, vargs);
672 devres_add(parent, ptr);
679 EXPORT_SYMBOL_GPL(__devm_iio_trigger_alloc);
681 static void devm_iio_trigger_unreg(void *trigger_info)
683 iio_trigger_unregister(trigger_info);
687 * devm_iio_trigger_register - Resource-managed iio_trigger_register()
688 * @dev: device this trigger was allocated for
689 * @trig_info: trigger to register
691 * Managed iio_trigger_register(). The IIO trigger registered with this
692 * function is automatically unregistered on driver detach. This function
693 * calls iio_trigger_register() internally. Refer to that function for more
697 * 0 on success, negative error number on failure.
699 int devm_iio_trigger_register(struct device *dev,
700 struct iio_trigger *trig_info)
704 ret = iio_trigger_register(trig_info);
708 return devm_add_action_or_reset(dev, devm_iio_trigger_unreg, trig_info);
710 EXPORT_SYMBOL_GPL(devm_iio_trigger_register);
712 bool iio_trigger_using_own(struct iio_dev *indio_dev)
714 return indio_dev->trig->attached_own_device;
716 EXPORT_SYMBOL(iio_trigger_using_own);
719 * iio_trigger_validate_own_device - Check if a trigger and IIO device belong to
721 * @trig: The IIO trigger to check
722 * @indio_dev: the IIO device to check
724 * This function can be used as the validate_device callback for triggers that
725 * can only be attached to their own device.
727 * Return: 0 if both the trigger and the IIO device belong to the same
728 * device, -EINVAL otherwise.
730 int iio_trigger_validate_own_device(struct iio_trigger *trig,
731 struct iio_dev *indio_dev)
733 if (indio_dev->dev.parent != trig->dev.parent)
737 EXPORT_SYMBOL(iio_trigger_validate_own_device);
739 int iio_device_register_trigger_consumer(struct iio_dev *indio_dev)
741 return iio_device_register_sysfs_group(indio_dev,
742 &iio_trigger_consumer_attr_group);
745 void iio_device_unregister_trigger_consumer(struct iio_dev *indio_dev)
747 /* Clean up an associated but not attached trigger reference */
749 iio_trigger_put(indio_dev->trig);