/drivers/staging/iio/industrialio-trigger.c

  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/module.h>
 12#include <linux/idr.h>
 13#include <linux/err.h>
 14#include <linux/device.h>
 15#include <linux/interrupt.h>
 16#include <linux/list.h>
 17#include <linux/slab.h>
 18
 19#include "iio.h"
 20#include "trigger.h"
 21#include "trigger_consumer.h"
 22
 23/* RFC - Question of approach
 24 * Make the common case (single sensor single trigger)
 25 * simple by starting trigger capture from when first sensors
 26 * is added.
 27 *
 28 * Complex simultaneous start requires use of 'hold' functionality
 29 * of the trigger. (not implemented)
 30 *
 31 * Any other suggestions?
 32 */
 33
 34static DEFINE_IDR(iio_trigger_idr);
 35static DEFINE_SPINLOCK(iio_trigger_idr_lock);
 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 = dev_get_drvdata(dev);
 49	return sprintf(buf, "%s\n", trig->name);
 50}
 51
 52static DEVICE_ATTR(name, S_IRUGO, iio_trigger_read_name, NULL);
 53
 54/**
 55 * iio_trigger_register_sysfs() - create a device for this trigger
 56 * @trig_info:	the trigger
 57 *
 58 * Also adds any control attribute registered by the trigger driver
 59 **/
 60static int iio_trigger_register_sysfs(struct iio_trigger *trig_info)
 61{
 62	return sysfs_add_file_to_group(&trig_info->dev.kobj,
 63				       &dev_attr_name.attr,
 64				       NULL);
 65}
 66
 67static void iio_trigger_unregister_sysfs(struct iio_trigger *trig_info)
 68{
 69	sysfs_remove_file_from_group(&trig_info->dev.kobj,
 70					   &dev_attr_name.attr,
 71					   NULL);
 72}
 73
 74
 75/**
 76 * iio_trigger_register_id() - get a unique id for this trigger
 77 * @trig_info:	the trigger
 78 **/
 79static int iio_trigger_register_id(struct iio_trigger *trig_info)
 80{
 81	int ret = 0;
 82
 83idr_again:
 84	if (unlikely(idr_pre_get(&iio_trigger_idr, GFP_KERNEL) == 0))
 85		return -ENOMEM;
 86
 87	spin_lock(&iio_trigger_idr_lock);
 88	ret = idr_get_new(&iio_trigger_idr, NULL, &trig_info->id);
 89	spin_unlock(&iio_trigger_idr_lock);
 90	if (unlikely(ret == -EAGAIN))
 91		goto idr_again;
 92	else if (likely(!ret))
 93		trig_info->id = trig_info->id & MAX_ID_MASK;
 94
 95	return ret;
 96}
 97
 98/**
 99 * iio_trigger_unregister_id() - free up unique id for use by another trigger
100 * @trig_info: the trigger
101 **/
102static void iio_trigger_unregister_id(struct iio_trigger *trig_info)
103{
104	spin_lock(&iio_trigger_idr_lock);
105	idr_remove(&iio_trigger_idr, trig_info->id);
106	spin_unlock(&iio_trigger_idr_lock);
107}
108
109int iio_trigger_register(struct iio_trigger *trig_info)
110{
111	int ret;
112
113	ret = iio_trigger_register_id(trig_info);
114	if (ret)
115		goto error_ret;
116	/* Set the name used for the sysfs directory etc */
117	dev_set_name(&trig_info->dev, "trigger%ld",
118		     (unsigned long) trig_info->id);
119
120	ret = device_add(&trig_info->dev);
121	if (ret)
122		goto error_unregister_id;
123
124	ret = iio_trigger_register_sysfs(trig_info);
125	if (ret)
126		goto error_device_del;
127
128	/* Add to list of available triggers held by the IIO core */
129	mutex_lock(&iio_trigger_list_lock);
130	list_add_tail(&trig_info->list, &iio_trigger_list);
131	mutex_unlock(&iio_trigger_list_lock);
132
133	return 0;
134
135error_device_del:
136	device_del(&trig_info->dev);
137error_unregister_id:
138	iio_trigger_unregister_id(trig_info);
139error_ret:
140	return ret;
141}
142EXPORT_SYMBOL(iio_trigger_register);
143
144void iio_trigger_unregister(struct iio_trigger *trig_info)
145{
146	mutex_lock(&iio_trigger_list_lock);
147	list_del(&trig_info->list);
148	mutex_unlock(&iio_trigger_list_lock);
149
150	iio_trigger_unregister_sysfs(trig_info);
151	iio_trigger_unregister_id(trig_info);
152	/* Possible issue in here */
153	device_unregister(&trig_info->dev);
154}
155EXPORT_SYMBOL(iio_trigger_unregister);
156
157static struct iio_trigger *iio_trigger_find_by_name(const char *name,
158						    size_t len)
159{
160	struct iio_trigger *trig = NULL, *iter;
161
162	mutex_lock(&iio_trigger_list_lock);
163	list_for_each_entry(iter, &iio_trigger_list, list)
164		if (sysfs_streq(iter->name, name)) {
165			trig = iter;
166			break;
167		}
168	mutex_unlock(&iio_trigger_list_lock);
169
170	return trig;
171}
172
173void iio_trigger_poll(struct iio_trigger *trig, s64 time)
174{
175	int i;
176	if (!trig->use_count) {
177		for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++)
178			if (trig->subirqs[i].enabled) {
179				trig->use_count++;
180				generic_handle_irq(trig->subirq_base + i);
181			}
182	}
183}
184EXPORT_SYMBOL(iio_trigger_poll);
185
186irqreturn_t iio_trigger_generic_data_rdy_poll(int irq, void *private)
187{
188	iio_trigger_poll(private, iio_get_time_ns());
189	return IRQ_HANDLED;
190}
191EXPORT_SYMBOL(iio_trigger_generic_data_rdy_poll);
192
193void iio_trigger_poll_chained(struct iio_trigger *trig, s64 time)
194{
195	int i;
196	if (!trig->use_count) {
197		for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++)
198			if (trig->subirqs[i].enabled) {
199				trig->use_count++;
200				handle_nested_irq(trig->subirq_base + i);
201			}
202	}
203}
204EXPORT_SYMBOL(iio_trigger_poll_chained);
205
206void iio_trigger_notify_done(struct iio_trigger *trig)
207{
208	trig->use_count--;
209	if (trig->use_count == 0 && trig->try_reenable)
210		if (trig->try_reenable(trig)) {
211			/* Missed and interrupt so launch new poll now */
212			iio_trigger_poll(trig, 0);
213		}
214}
215EXPORT_SYMBOL(iio_trigger_notify_done);
216
217/* Trigger Consumer related functions */
218
219/* Complexity in here.  With certain triggers (datardy) an acknowledgement
220 * may be needed if the pollfuncs do not include the data read for the
221 * triggering device.
222 * This is not currently handled.  Alternative of not enabling trigger unless
223 * the relevant function is in there may be the best option.
224 */
225/* Worth protecting against double additions?*/
226int iio_trigger_attach_poll_func(struct iio_trigger *trig,
227				 struct iio_poll_func *pf)
228{
229	int ret = 0;
230	bool notinuse
231		= bitmap_empty(trig->pool, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
232
233	pf->irq = iio_trigger_get_irq(trig);
234	ret = request_threaded_irq(pf->irq, pf->h, pf->thread,
235				   pf->type, pf->name,
236				   pf);
237	if (trig->set_trigger_state && notinuse)
238		ret = trig->set_trigger_state(trig, true);
239
240	return ret;
241}
242EXPORT_SYMBOL(iio_trigger_attach_poll_func);
243
244int iio_trigger_dettach_poll_func(struct iio_trigger *trig,
245				  struct iio_poll_func *pf)
246{
247	int ret = 0;
248	bool no_other_users
249		= (bitmap_weight(trig->pool,
250				 CONFIG_IIO_CONSUMERS_PER_TRIGGER)
251		   == 1);
252	if (trig->set_trigger_state && no_other_users) {
253		ret = trig->set_trigger_state(trig, false);
254		if (ret)
255			goto error_ret;
256	}
257	iio_trigger_put_irq(trig, pf->irq);
258	free_irq(pf->irq, pf);
259
260error_ret:
261	return ret;
262}
263EXPORT_SYMBOL(iio_trigger_dettach_poll_func);
264
265irqreturn_t iio_pollfunc_store_time(int irq, void *p)
266{
267	struct iio_poll_func *pf = p;
268	pf->timestamp = iio_get_time_ns();
269	return IRQ_WAKE_THREAD;
270}
271EXPORT_SYMBOL(iio_pollfunc_store_time);
272
273struct iio_poll_func
274*iio_alloc_pollfunc(irqreturn_t (*h)(int irq, void *p),
275		    irqreturn_t (*thread)(int irq, void *p),
276		    int type,
277		    void *private,
278		    const char *fmt,
279		    ...)
280{
281	va_list vargs;
282	struct iio_poll_func *pf;
283
284	pf = kmalloc(sizeof *pf, GFP_KERNEL);
285	if (pf == NULL)
286		return NULL;
287	va_start(vargs, fmt);
288	pf->name = kvasprintf(GFP_KERNEL, fmt, vargs);
289	va_end(vargs);
290	if (pf->name == NULL) {
291		kfree(pf);
292		return NULL;
293	}
294	pf->h = h;
295	pf->thread = thread;
296	pf->type = type;
297	pf->private_data = private;
298
299	return pf;
300}
301EXPORT_SYMBOL_GPL(iio_alloc_pollfunc);
302
303void iio_dealloc_pollfunc(struct iio_poll_func *pf)
304{
305	kfree(pf->name);
306	kfree(pf);
307}
308EXPORT_SYMBOL_GPL(iio_dealloc_pollfunc);
309
310/**
311 * iio_trigger_read_currrent() - trigger consumer sysfs query which trigger
312 *
313 * For trigger consumers the current_trigger interface allows the trigger
314 * used by the device to be queried.
315 **/
316static ssize_t iio_trigger_read_current(struct device *dev,
317					struct device_attribute *attr,
318					char *buf)
319{
320	struct iio_dev *dev_info = dev_get_drvdata(dev);
321	int len = 0;
322	if (dev_info->trig)
323		len = sprintf(buf,
324			      "%s\n",
325			      dev_info->trig->name);
326	return len;
327}
328
329/**
330 * iio_trigger_write_current() trigger consumer sysfs set current trigger
331 *
332 * For trigger consumers the current_trigger interface allows the trigger
333 * used for this device to be specified at run time based on the triggers
334 * name.
335 **/
336static ssize_t iio_trigger_write_current(struct device *dev,
337					 struct device_attribute *attr,
338					 const char *buf,
339					 size_t len)
340{
341	struct iio_dev *dev_info = dev_get_drvdata(dev);
342	struct iio_trigger *oldtrig = dev_info->trig;
343	mutex_lock(&dev_info->mlock);
344	if (dev_info->currentmode == INDIO_RING_TRIGGERED) {
345		mutex_unlock(&dev_info->mlock);
346		return -EBUSY;
347	}
348	mutex_unlock(&dev_info->mlock);
349
350	dev_info->trig = iio_trigger_find_by_name(buf, len);
351	if (oldtrig && dev_info->trig != oldtrig)
352		iio_put_trigger(oldtrig);
353	if (dev_info->trig)
354		iio_get_trigger(dev_info->trig);
355
356	return len;
357}
358
359static DEVICE_ATTR(current_trigger, S_IRUGO | S_IWUSR,
360		   iio_trigger_read_current,
361		   iio_trigger_write_current);
362
363static struct attribute *iio_trigger_consumer_attrs[] = {
364	&dev_attr_current_trigger.attr,
365	NULL,
366};
367
368static const struct attribute_group iio_trigger_consumer_attr_group = {
369	.name = "trigger",
370	.attrs = iio_trigger_consumer_attrs,
371};
372
373static void iio_trig_release(struct device *device)
374{
375	struct iio_trigger *trig = to_iio_trigger(device);
376	int i;
377
378	if (trig->subirq_base) {
379		for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
380			irq_modify_status(trig->subirq_base + i,
381					  IRQ_NOAUTOEN,
382					  IRQ_NOREQUEST | IRQ_NOPROBE);
383			irq_set_chip(trig->subirq_base + i,
384				     NULL);
385			irq_set_handler(trig->subirq_base + i,
386					NULL);
387		}
388
389		irq_free_descs(trig->subirq_base,
390			       CONFIG_IIO_CONSUMERS_PER_TRIGGER);
391	}
392	kfree(trig->name);
393	kfree(trig);
394	iio_put();
395}
396
397static struct device_type iio_trig_type = {
398	.release = iio_trig_release,
399};
400
401static void iio_trig_subirqmask(struct irq_data *d)
402{
403	struct irq_chip *chip = irq_data_get_irq_chip(d);
404	struct iio_trigger *trig
405		= container_of(chip,
406			       struct iio_trigger, subirq_chip);
407	trig->subirqs[d->irq - trig->subirq_base].enabled = false;
408}
409
410static void iio_trig_subirqunmask(struct irq_data *d)
411{
412	struct irq_chip *chip = irq_data_get_irq_chip(d);
413	struct iio_trigger *trig
414		= container_of(chip,
415			       struct iio_trigger, subirq_chip);
416	trig->subirqs[d->irq - trig->subirq_base].enabled = true;
417}
418
419struct iio_trigger *iio_allocate_trigger(const char *fmt, ...)
420{
421	va_list vargs;
422	struct iio_trigger *trig;
423	trig = kzalloc(sizeof *trig, GFP_KERNEL);
424	if (trig) {
425		int i;
426		trig->dev.type = &iio_trig_type;
427		trig->dev.bus = &iio_bus_type;
428		device_initialize(&trig->dev);
429		dev_set_drvdata(&trig->dev, (void *)trig);
430
431		mutex_init(&trig->pool_lock);
432		trig->subirq_base
433			= irq_alloc_descs(-1, 0,
434					  CONFIG_IIO_CONSUMERS_PER_TRIGGER,
435					  0);
436		if (trig->subirq_base < 0) {
437			kfree(trig);
438			return NULL;
439		}
440		va_start(vargs, fmt);
441		trig->name = kvasprintf(GFP_KERNEL, fmt, vargs);
442		va_end(vargs);
443		if (trig->name == NULL) {
444			irq_free_descs(trig->subirq_base,
445				       CONFIG_IIO_CONSUMERS_PER_TRIGGER);
446			kfree(trig);
447			return NULL;
448		}
449		trig->subirq_chip.name = trig->name;
450		trig->subirq_chip.irq_mask = &iio_trig_subirqmask;
451		trig->subirq_chip.irq_unmask = &iio_trig_subirqunmask;
452		for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
453			irq_set_chip(trig->subirq_base + i,
454				     &trig->subirq_chip);
455			irq_set_handler(trig->subirq_base + i,
456					&handle_simple_irq);
457			irq_modify_status(trig->subirq_base + i,
458					  IRQ_NOREQUEST | IRQ_NOAUTOEN,
459					  IRQ_NOPROBE);
460		}
461		iio_get();
462	}
463	return trig;
464}
465EXPORT_SYMBOL(iio_allocate_trigger);
466
467void iio_free_trigger(struct iio_trigger *trig)
468{
469	if (trig)
470		put_device(&trig->dev);
471}
472EXPORT_SYMBOL(iio_free_trigger);
473
474int iio_device_register_trigger_consumer(struct iio_dev *dev_info)
475{
476	int ret;
477	ret = sysfs_create_group(&dev_info->dev.kobj,
478				 &iio_trigger_consumer_attr_group);
479	return ret;
480}
481EXPORT_SYMBOL(iio_device_register_trigger_consumer);
482
483int iio_device_unregister_trigger_consumer(struct iio_dev *dev_info)
484{
485	sysfs_remove_group(&dev_info->dev.kobj,
486			   &iio_trigger_consumer_attr_group);
487	return 0;
488}
489EXPORT_SYMBOL(iio_device_unregister_trigger_consumer);
490
491int iio_triggered_ring_postenable(struct iio_dev *indio_dev)
492{
493	return indio_dev->trig
494		? iio_trigger_attach_poll_func(indio_dev->trig,
495					       indio_dev->pollfunc)
496		: 0;
497}
498EXPORT_SYMBOL(iio_triggered_ring_postenable);
499
500int iio_triggered_ring_predisable(struct iio_dev *indio_dev)
501{
502	return indio_dev->trig
503		? iio_trigger_dettach_poll_func(indio_dev->trig,
504						indio_dev->pollfunc)
505		: 0;
506}
507EXPORT_SYMBOL(iio_triggered_ring_predisable);