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/cleanup.h>
8 #include <linux/kernel.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>
16 #include <linux/iio/iio.h>
17 #include <linux/iio/iio-opaque.h>
18 #include <linux/iio/trigger.h>
20 #include "iio_core_trigger.h"
21 #include <linux/iio/trigger_consumer.h>
23 /* RFC - Question of approach
24 * Make the common case (single sensor single trigger)
25 * simple by starting trigger capture from when first sensors
28 * Complex simultaneous start requires use of 'hold' functionality
29 * of the trigger. (not implemented)
31 * Any other suggestions?
34 static DEFINE_IDA(iio_trigger_ida);
36 /* Single list of all available triggers */
37 static LIST_HEAD(iio_trigger_list);
38 static DEFINE_MUTEX(iio_trigger_list_lock);
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
45 * @buf: buffer to print the name into
47 * Return: a negative number on failure or the number of written
48 * characters on success.
50 static ssize_t name_show(struct device *dev, struct device_attribute *attr,
53 struct iio_trigger *trig = to_iio_trigger(dev);
55 return sysfs_emit(buf, "%s\n", trig->name);
58 static DEVICE_ATTR_RO(name);
60 static struct attribute *iio_trig_dev_attrs[] = {
64 ATTRIBUTE_GROUPS(iio_trig_dev);
66 static struct iio_trigger *__iio_trigger_find_by_name(const char *name);
68 int iio_trigger_register(struct iio_trigger *trig_info)
72 trig_info->id = ida_alloc(&iio_trigger_ida, GFP_KERNEL);
73 if (trig_info->id < 0)
76 /* Set the name used for the sysfs directory etc */
77 dev_set_name(&trig_info->dev, "trigger%d", trig_info->id);
79 ret = device_add(&trig_info->dev);
81 goto error_unregister_id;
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);
88 goto error_device_del;
90 list_add_tail(&trig_info->list, &iio_trigger_list);
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 scoped_guard(mutex, &iio_trigger_list_lock)
106 list_del(&trig_info->list);
108 ida_free(&iio_trigger_ida, trig_info->id);
109 /* Possible issue in here */
110 device_del(&trig_info->dev);
112 EXPORT_SYMBOL(iio_trigger_unregister);
114 int iio_trigger_set_immutable(struct iio_dev *indio_dev, struct iio_trigger *trig)
116 struct iio_dev_opaque *iio_dev_opaque;
118 if (!indio_dev || !trig)
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);
125 indio_dev->trig = iio_trigger_get(trig);
126 iio_dev_opaque->trig_readonly = true;
130 EXPORT_SYMBOL(iio_trigger_set_immutable);
132 /* Search for trigger by name, assuming iio_trigger_list_lock held */
133 static struct iio_trigger *__iio_trigger_find_by_name(const char *name)
135 struct iio_trigger *iter;
137 list_for_each_entry(iter, &iio_trigger_list, list)
138 if (!strcmp(iter->name, name))
144 static struct iio_trigger *iio_trigger_acquire_by_name(const char *name)
146 struct iio_trigger *iter;
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);
156 static void iio_reenable_work_fn(struct work_struct *work)
158 struct iio_trigger *trig = container_of(work, struct iio_trigger,
162 * This 'might' occur after the trigger state is set to disabled -
163 * in that case the driver should skip reenabling.
165 trig->ops->reenable(trig);
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.
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.
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.
182 static void iio_trigger_notify_done_atomic(struct iio_trigger *trig)
184 if (atomic_dec_and_test(&trig->use_count) && trig->ops &&
186 schedule_work(&trig->reenable_work);
190 * iio_trigger_poll() - Call the IRQ trigger handler of the consumers
191 * @trig: trigger which occurred
193 * This function should only be called from a hard IRQ context.
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);
220 * iio_trigger_poll_nested() - Call the threaded trigger handler of the
222 * @trig: trigger which occurred
224 * This function should only be called from a kernel thread context.
226 void iio_trigger_poll_nested(struct iio_trigger *trig)
230 if (!atomic_read(&trig->use_count)) {
231 atomic_set(&trig->use_count, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
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);
237 iio_trigger_notify_done(trig);
241 EXPORT_SYMBOL(iio_trigger_poll_nested);
243 void iio_trigger_notify_done(struct iio_trigger *trig)
245 if (atomic_dec_and_test(&trig->use_count) && trig->ops &&
247 trig->ops->reenable(trig);
249 EXPORT_SYMBOL(iio_trigger_notify_done);
251 /* Trigger Consumer related functions */
252 static int iio_trigger_get_irq(struct iio_trigger *trig)
256 scoped_guard(mutex, &trig->pool_lock) {
257 ret = bitmap_find_free_region(trig->pool,
258 CONFIG_IIO_CONSUMERS_PER_TRIGGER,
264 return ret + trig->subirq_base;
267 static void iio_trigger_put_irq(struct iio_trigger *trig, int irq)
269 guard(mutex)(&trig->pool_lock);
270 clear_bit(irq - trig->subirq_base, trig->pool);
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
276 * This is not currently handled. Alternative of not enabling trigger unless
277 * the relevant function is in there may be the best option.
279 /* Worth protecting against double additions? */
280 int iio_trigger_attach_poll_func(struct iio_trigger *trig,
281 struct iio_poll_func *pf)
283 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(pf->indio_dev);
285 bitmap_empty(trig->pool, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
288 /* Prevent the module from being removed whilst attached to a trigger */
289 __module_get(iio_dev_opaque->driver_module);
292 pf->irq = iio_trigger_get_irq(trig);
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);
300 ret = request_threaded_irq(pf->irq, pf->h, pf->thread,
306 /* Enable trigger in driver */
307 if (trig->ops && trig->ops->set_trigger_state && notinuse) {
308 ret = trig->ops->set_trigger_state(trig, true);
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.
318 if (!iio_validate_own_trigger(pf->indio_dev, trig))
319 trig->attached_own_device = true;
324 free_irq(pf->irq, pf);
326 iio_trigger_put_irq(trig, pf->irq);
328 module_put(iio_dev_opaque->driver_module);
332 int iio_trigger_detach_poll_func(struct iio_trigger *trig,
333 struct iio_poll_func *pf)
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;
340 if (trig->ops && trig->ops->set_trigger_state && no_other_users) {
341 ret = trig->ops->set_trigger_state(trig, false);
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);
354 irqreturn_t iio_pollfunc_store_time(int irq, void *p)
356 struct iio_poll_func *pf = p;
358 pf->timestamp = iio_get_time_ns(pf->indio_dev);
359 return IRQ_WAKE_THREAD;
361 EXPORT_SYMBOL(iio_pollfunc_store_time);
364 *iio_alloc_pollfunc(irqreturn_t (*h)(int irq, void *p),
365 irqreturn_t (*thread)(int irq, void *p),
367 struct iio_dev *indio_dev,
372 struct iio_poll_func *pf;
374 pf = kmalloc(sizeof(*pf), GFP_KERNEL);
377 va_start(vargs, fmt);
378 pf->name = kvasprintf(GFP_KERNEL, fmt, vargs);
380 if (pf->name == NULL) {
387 pf->indio_dev = indio_dev;
391 EXPORT_SYMBOL_GPL(iio_alloc_pollfunc);
393 void iio_dealloc_pollfunc(struct iio_poll_func *pf)
398 EXPORT_SYMBOL_GPL(iio_dealloc_pollfunc);
401 * current_trigger_show() - trigger consumer sysfs query current trigger
402 * @dev: device associated with an industrial I/O device
403 * @attr: pointer to the device_attribute structure that
405 * @buf: buffer where the current trigger name will be printed into
407 * For trigger consumers the current_trigger interface allows the trigger
408 * used by the device to be queried.
410 * Return: a negative number on failure, the number of characters written
411 * on success or 0 if no trigger is available
413 static ssize_t current_trigger_show(struct device *dev,
414 struct device_attribute *attr, char *buf)
416 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
419 return sysfs_emit(buf, "%s\n", indio_dev->trig->name);
424 * current_trigger_store() - trigger consumer sysfs set current trigger
425 * @dev: device associated with an industrial I/O device
426 * @attr: device attribute that is being processed
427 * @buf: string buffer that holds the name of the trigger
428 * @len: length of the trigger name held by buf
430 * For trigger consumers the current_trigger interface allows the trigger
431 * used for this device to be specified at run time based on the trigger's
434 * Return: negative error code on failure or length of the buffer
437 static ssize_t current_trigger_store(struct device *dev,
438 struct device_attribute *attr,
439 const char *buf, size_t len)
441 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
442 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
443 struct iio_trigger *oldtrig = indio_dev->trig;
444 struct iio_trigger *trig;
447 scoped_guard(mutex, &iio_dev_opaque->mlock) {
448 if (iio_dev_opaque->currentmode == INDIO_BUFFER_TRIGGERED)
450 if (iio_dev_opaque->trig_readonly)
454 trig = iio_trigger_acquire_by_name(buf);
455 if (oldtrig == trig) {
457 goto out_trigger_put;
460 if (trig && indio_dev->info->validate_trigger) {
461 ret = indio_dev->info->validate_trigger(indio_dev, trig);
463 goto out_trigger_put;
466 if (trig && trig->ops && trig->ops->validate_device) {
467 ret = trig->ops->validate_device(trig, indio_dev);
469 goto out_trigger_put;
472 indio_dev->trig = trig;
475 if (indio_dev->modes & INDIO_EVENT_TRIGGERED)
476 iio_trigger_detach_poll_func(oldtrig,
477 indio_dev->pollfunc_event);
478 iio_trigger_put(oldtrig);
480 if (indio_dev->trig) {
481 if (indio_dev->modes & INDIO_EVENT_TRIGGERED)
482 iio_trigger_attach_poll_func(indio_dev->trig,
483 indio_dev->pollfunc_event);
490 iio_trigger_put(trig);
494 static DEVICE_ATTR_RW(current_trigger);
496 static struct attribute *iio_trigger_consumer_attrs[] = {
497 &dev_attr_current_trigger.attr,
501 static const struct attribute_group iio_trigger_consumer_attr_group = {
503 .attrs = iio_trigger_consumer_attrs,
506 static void iio_trig_release(struct device *device)
508 struct iio_trigger *trig = to_iio_trigger(device);
511 if (trig->subirq_base) {
512 for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
513 irq_modify_status(trig->subirq_base + i,
515 IRQ_NOREQUEST | IRQ_NOPROBE);
516 irq_set_chip(trig->subirq_base + i,
518 irq_set_handler(trig->subirq_base + i,
522 irq_free_descs(trig->subirq_base,
523 CONFIG_IIO_CONSUMERS_PER_TRIGGER);
529 static const struct device_type iio_trig_type = {
530 .release = iio_trig_release,
531 .groups = iio_trig_dev_groups,
534 static void iio_trig_subirqmask(struct irq_data *d)
536 struct irq_chip *chip = irq_data_get_irq_chip(d);
537 struct iio_trigger *trig = container_of(chip, struct iio_trigger, subirq_chip);
539 trig->subirqs[d->irq - trig->subirq_base].enabled = false;
542 static void iio_trig_subirqunmask(struct irq_data *d)
544 struct irq_chip *chip = irq_data_get_irq_chip(d);
545 struct iio_trigger *trig = container_of(chip, struct iio_trigger, subirq_chip);
547 trig->subirqs[d->irq - trig->subirq_base].enabled = true;
550 static __printf(3, 0)
551 struct iio_trigger *viio_trigger_alloc(struct device *parent,
552 struct module *this_mod,
556 struct iio_trigger *trig;
559 trig = kzalloc(sizeof(*trig), GFP_KERNEL);
563 trig->dev.parent = parent;
564 trig->dev.type = &iio_trig_type;
565 trig->dev.bus = &iio_bus_type;
566 device_initialize(&trig->dev);
567 INIT_WORK(&trig->reenable_work, iio_reenable_work_fn);
569 mutex_init(&trig->pool_lock);
570 trig->subirq_base = irq_alloc_descs(-1, 0,
571 CONFIG_IIO_CONSUMERS_PER_TRIGGER,
573 if (trig->subirq_base < 0)
576 trig->name = kvasprintf(GFP_KERNEL, fmt, vargs);
577 if (trig->name == NULL)
580 INIT_LIST_HEAD(&trig->list);
582 trig->owner = this_mod;
584 trig->subirq_chip.name = trig->name;
585 trig->subirq_chip.irq_mask = &iio_trig_subirqmask;
586 trig->subirq_chip.irq_unmask = &iio_trig_subirqunmask;
587 for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
588 irq_set_chip(trig->subirq_base + i, &trig->subirq_chip);
589 irq_set_handler(trig->subirq_base + i, &handle_simple_irq);
590 irq_modify_status(trig->subirq_base + i,
591 IRQ_NOREQUEST | IRQ_NOAUTOEN, IRQ_NOPROBE);
597 irq_free_descs(trig->subirq_base, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
604 * __iio_trigger_alloc - Allocate a trigger
605 * @parent: Device to allocate iio_trigger for
606 * @this_mod: module allocating the trigger
607 * @fmt: trigger name format. If it includes format
608 * specifiers, the additional arguments following
609 * format are formatted and inserted in the resulting
610 * string replacing their respective specifiers.
612 * Pointer to allocated iio_trigger on success, NULL on failure.
614 struct iio_trigger *__iio_trigger_alloc(struct device *parent,
615 struct module *this_mod,
616 const char *fmt, ...)
618 struct iio_trigger *trig;
621 va_start(vargs, fmt);
622 trig = viio_trigger_alloc(parent, this_mod, fmt, vargs);
627 EXPORT_SYMBOL(__iio_trigger_alloc);
629 void iio_trigger_free(struct iio_trigger *trig)
632 put_device(&trig->dev);
634 EXPORT_SYMBOL(iio_trigger_free);
636 static void devm_iio_trigger_release(struct device *dev, void *res)
638 iio_trigger_free(*(struct iio_trigger **)res);
642 * __devm_iio_trigger_alloc - Resource-managed iio_trigger_alloc()
643 * Managed iio_trigger_alloc. iio_trigger allocated with this function is
644 * automatically freed on driver detach.
645 * @parent: Device to allocate iio_trigger for
646 * @this_mod: module allocating the trigger
647 * @fmt: trigger name format. If it includes format
648 * specifiers, the additional arguments following
649 * format are formatted and inserted in the resulting
650 * string replacing their respective specifiers.
654 * Pointer to allocated iio_trigger on success, NULL on failure.
656 struct iio_trigger *__devm_iio_trigger_alloc(struct device *parent,
657 struct module *this_mod,
658 const char *fmt, ...)
660 struct iio_trigger **ptr, *trig;
663 ptr = devres_alloc(devm_iio_trigger_release, sizeof(*ptr),
668 /* use raw alloc_dr for kmalloc caller tracing */
669 va_start(vargs, fmt);
670 trig = viio_trigger_alloc(parent, this_mod, fmt, vargs);
674 devres_add(parent, ptr);
681 EXPORT_SYMBOL_GPL(__devm_iio_trigger_alloc);
683 static void devm_iio_trigger_unreg(void *trigger_info)
685 iio_trigger_unregister(trigger_info);
689 * devm_iio_trigger_register - Resource-managed iio_trigger_register()
690 * @dev: device this trigger was allocated for
691 * @trig_info: trigger to register
693 * Managed iio_trigger_register(). The IIO trigger registered with this
694 * function is automatically unregistered on driver detach. This function
695 * calls iio_trigger_register() internally. Refer to that function for more
699 * 0 on success, negative error number on failure.
701 int devm_iio_trigger_register(struct device *dev,
702 struct iio_trigger *trig_info)
706 ret = iio_trigger_register(trig_info);
710 return devm_add_action_or_reset(dev, devm_iio_trigger_unreg, trig_info);
712 EXPORT_SYMBOL_GPL(devm_iio_trigger_register);
714 bool iio_trigger_using_own(struct iio_dev *indio_dev)
716 return indio_dev->trig->attached_own_device;
718 EXPORT_SYMBOL(iio_trigger_using_own);
721 * iio_validate_own_trigger - Check if a trigger and IIO device belong to
723 * @idev: the IIO device to check
724 * @trig: the IIO trigger to check
726 * This function can be used as the validate_trigger callback for triggers that
727 * can only be attached to their own device.
729 * Return: 0 if both the trigger and the IIO device belong to the same
730 * device, -EINVAL otherwise.
732 int iio_validate_own_trigger(struct iio_dev *idev, struct iio_trigger *trig)
734 if (idev->dev.parent != trig->dev.parent)
738 EXPORT_SYMBOL_GPL(iio_validate_own_trigger);
741 * iio_trigger_validate_own_device - Check if a trigger and IIO device belong to
743 * @trig: The IIO trigger to check
744 * @indio_dev: the IIO device to check
746 * This function can be used as the validate_device callback for triggers that
747 * can only be attached to their own device.
749 * Return: 0 if both the trigger and the IIO device belong to the same
750 * device, -EINVAL otherwise.
752 int iio_trigger_validate_own_device(struct iio_trigger *trig,
753 struct iio_dev *indio_dev)
755 if (indio_dev->dev.parent != trig->dev.parent)
759 EXPORT_SYMBOL(iio_trigger_validate_own_device);
761 int iio_device_register_trigger_consumer(struct iio_dev *indio_dev)
763 return iio_device_register_sysfs_group(indio_dev,
764 &iio_trigger_consumer_attr_group);
767 void iio_device_unregister_trigger_consumer(struct iio_dev *indio_dev)
769 /* Clean up an associated but not attached trigger reference */
771 iio_trigger_put(indio_dev->trig);