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)
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);
137	return IRQ_HANDLED;
138}
139EXPORT_SYMBOL(iio_trigger_generic_data_rdy_poll);
140
141void iio_trigger_poll_chained(struct iio_trigger *trig)
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);
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);
584