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 "iio.h"
19#include "trigger.h"
20#include "iio_core.h"
21#include "iio_core_trigger.h"
22#include "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 = 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
74int iio_trigger_register(struct iio_trigger *trig_info)
75{
76	int ret;
77
78	trig_info->id = ida_simple_get(&iio_trigger_ida, 0, 0, GFP_KERNEL);
79	if (trig_info->id < 0) {
80		ret = trig_info->id;
81		goto error_ret;
82	}
83	/* Set the name used for the sysfs directory etc */
84	dev_set_name(&trig_info->dev, "trigger%ld",
85		     (unsigned long) trig_info->id);
86
87	ret = device_add(&trig_info->dev);
88	if (ret)
89		goto error_unregister_id;
90
91	ret = iio_trigger_register_sysfs(trig_info);
92	if (ret)
93		goto error_device_del;
94
95	/* Add to list of available triggers held by the IIO core */
96	mutex_lock(&iio_trigger_list_lock);
97	list_add_tail(&trig_info->list, &iio_trigger_list);
98	mutex_unlock(&iio_trigger_list_lock);
99
100	return 0;
101
102error_device_del:
103	device_del(&trig_info->dev);
104error_unregister_id:
105	ida_simple_remove(&iio_trigger_ida, trig_info->id);
106error_ret:
107	return ret;
108}
109EXPORT_SYMBOL(iio_trigger_register);
110
111void iio_trigger_unregister(struct iio_trigger *trig_info)
112{
113	mutex_lock(&iio_trigger_list_lock);
114	list_del(&trig_info->list);
115	mutex_unlock(&iio_trigger_list_lock);
116
117	iio_trigger_unregister_sysfs(trig_info);
118	ida_simple_remove(&iio_trigger_ida, trig_info->id);
119	/* Possible issue in here */
120	device_unregister(&trig_info->dev);
121}
122EXPORT_SYMBOL(iio_trigger_unregister);
123
124static struct iio_trigger *iio_trigger_find_by_name(const char *name,
125						    size_t len)
126{
127	struct iio_trigger *trig = NULL, *iter;
128
129	mutex_lock(&iio_trigger_list_lock);
130	list_for_each_entry(iter, &iio_trigger_list, list)
131		if (sysfs_streq(iter->name, name)) {
132			trig = iter;
133			break;
134		}
135	mutex_unlock(&iio_trigger_list_lock);
136
137	return trig;
138}
139
140void iio_trigger_poll(struct iio_trigger *trig, s64 time)
141{
142	int i;
143	if (!trig->use_count)
144		for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++)
145			if (trig->subirqs[i].enabled) {
146				trig->use_count++;
147				generic_handle_irq(trig->subirq_base + i);
148			}
149}
150EXPORT_SYMBOL(iio_trigger_poll);
151
152irqreturn_t iio_trigger_generic_data_rdy_poll(int irq, void *private)
153{
154	iio_trigger_poll(private, iio_get_time_ns());
155	return IRQ_HANDLED;
156}
157EXPORT_SYMBOL(iio_trigger_generic_data_rdy_poll);
158
159void iio_trigger_poll_chained(struct iio_trigger *trig, s64 time)
160{
161	int i;
162	if (!trig->use_count)
163		for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++)
164			if (trig->subirqs[i].enabled) {
165				trig->use_count++;
166				handle_nested_irq(trig->subirq_base + i);
167			}
168}
169EXPORT_SYMBOL(iio_trigger_poll_chained);
170
171void iio_trigger_notify_done(struct iio_trigger *trig)
172{
173	trig->use_count--;
174	if (trig->use_count == 0 && trig->ops && trig->ops->try_reenable)
175		if (trig->ops->try_reenable(trig))
176			/* Missed and interrupt so launch new poll now */
177			iio_trigger_poll(trig, 0);
178}
179EXPORT_SYMBOL(iio_trigger_notify_done);
180
181/* Trigger Consumer related functions */
182static int iio_trigger_get_irq(struct iio_trigger *trig)
183{
184	int ret;
185	mutex_lock(&trig->pool_lock);
186	ret = bitmap_find_free_region(trig->pool,
187				      CONFIG_IIO_CONSUMERS_PER_TRIGGER,
188				      ilog2(1));
189	mutex_unlock(&trig->pool_lock);
190	if (ret >= 0)
191		ret += trig->subirq_base;
192
193	return ret;
194}
195
196static void iio_trigger_put_irq(struct iio_trigger *trig, int irq)
197{
198	mutex_lock(&trig->pool_lock);
199	clear_bit(irq - trig->subirq_base, trig->pool);
200	mutex_unlock(&trig->pool_lock);
201}
202
203/* Complexity in here.  With certain triggers (datardy) an acknowledgement
204 * may be needed if the pollfuncs do not include the data read for the
205 * triggering device.
206 * This is not currently handled.  Alternative of not enabling trigger unless
207 * the relevant function is in there may be the best option.
208 */
209/* Worth protecting against double additions?*/
210static int iio_trigger_attach_poll_func(struct iio_trigger *trig,
211					struct iio_poll_func *pf)
212{
213	int ret = 0;
214	bool notinuse
215		= bitmap_empty(trig->pool, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
216
217	/* Prevent the module being removed whilst attached to a trigger */
218	__module_get(pf->indio_dev->info->driver_module);
219	pf->irq = iio_trigger_get_irq(trig);
220	ret = request_threaded_irq(pf->irq, pf->h, pf->thread,
221				   pf->type, pf->name,
222				   pf);
223	if (ret < 0) {
224		module_put(pf->indio_dev->info->driver_module);
225		return ret;
226	}
227
228	if (trig->ops && trig->ops->set_trigger_state && notinuse) {
229		ret = trig->ops->set_trigger_state(trig, true);
230		if (ret < 0)
231			module_put(pf->indio_dev->info->driver_module);
232	}
233
234	return ret;
235}
236
237static int iio_trigger_dettach_poll_func(struct iio_trigger *trig,
238					 struct iio_poll_func *pf)
239{
240	int ret = 0;
241	bool no_other_users
242		= (bitmap_weight(trig->pool,
243				 CONFIG_IIO_CONSUMERS_PER_TRIGGER)
244		   == 1);
245	if (trig->ops && trig->ops->set_trigger_state && no_other_users) {
246		ret = trig->ops->set_trigger_state(trig, false);
247		if (ret)
248			goto error_ret;
249	}
250	iio_trigger_put_irq(trig, pf->irq);
251	free_irq(pf->irq, pf);
252	module_put(pf->indio_dev->info->driver_module);
253
254error_ret:
255	return ret;
256}
257
258irqreturn_t iio_pollfunc_store_time(int irq, void *p)
259{
260	struct iio_poll_func *pf = p;
261	pf->timestamp = iio_get_time_ns();
262	return IRQ_WAKE_THREAD;
263}
264EXPORT_SYMBOL(iio_pollfunc_store_time);
265
266struct iio_poll_func
267*iio_alloc_pollfunc(irqreturn_t (*h)(int irq, void *p),
268		    irqreturn_t (*thread)(int irq, void *p),
269		    int type,
270		    struct iio_dev *indio_dev,
271		    const char *fmt,
272		    ...)
273{
274	va_list vargs;
275	struct iio_poll_func *pf;
276
277	pf = kmalloc(sizeof *pf, GFP_KERNEL);
278	if (pf == NULL)
279		return NULL;
280	va_start(vargs, fmt);
281	pf->name = kvasprintf(GFP_KERNEL, fmt, vargs);
282	va_end(vargs);
283	if (pf->name == NULL) {
284		kfree(pf);
285		return NULL;
286	}
287	pf->h = h;
288	pf->thread = thread;
289	pf->type = type;
290	pf->indio_dev = indio_dev;
291
292	return pf;
293}
294EXPORT_SYMBOL_GPL(iio_alloc_pollfunc);
295
296void iio_dealloc_pollfunc(struct iio_poll_func *pf)
297{
298	kfree(pf->name);
299	kfree(pf);
300}
301EXPORT_SYMBOL_GPL(iio_dealloc_pollfunc);
302
303/**
304 * iio_trigger_read_current() - trigger consumer sysfs query which trigger
305 *
306 * For trigger consumers the current_trigger interface allows the trigger
307 * used by the device to be queried.
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_get_drvdata(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 *
323 * For trigger consumers the current_trigger interface allows the trigger
324 * used for this device to be specified at run time based on the triggers
325 * name.
326 **/
327static ssize_t iio_trigger_write_current(struct device *dev,
328					 struct device_attribute *attr,
329					 const char *buf,
330					 size_t len)
331{
332	struct iio_dev *indio_dev = dev_get_drvdata(dev);
333	struct iio_trigger *oldtrig = indio_dev->trig;
334	struct iio_trigger *trig;
335	int ret;
336
337	mutex_lock(&indio_dev->mlock);
338	if (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED) {
339		mutex_unlock(&indio_dev->mlock);
340		return -EBUSY;
341	}
342	mutex_unlock(&indio_dev->mlock);
343
344	trig = iio_trigger_find_by_name(buf, len);
345	if (oldtrig == trig)
346		return len;
347
348	if (trig && indio_dev->info->validate_trigger) {
349		ret = indio_dev->info->validate_trigger(indio_dev, trig);
350		if (ret)
351			return ret;
352	}
353
354	if (trig && trig->ops && trig->ops->validate_device) {
355		ret = trig->ops->validate_device(trig, indio_dev);
356		if (ret)
357			return ret;
358	}
359
360	indio_dev->trig = trig;
361
362	if (oldtrig && indio_dev->trig != oldtrig)
363		iio_put_trigger(oldtrig);
364	if (indio_dev->trig)
365		iio_get_trigger(indio_dev->trig);
366
367	return len;
368}
369
370static DEVICE_ATTR(current_trigger, S_IRUGO | S_IWUSR,
371		   iio_trigger_read_current,
372		   iio_trigger_write_current);
373
374static struct attribute *iio_trigger_consumer_attrs[] = {
375	&dev_attr_current_trigger.attr,
376	NULL,
377};
378
379static const struct attribute_group iio_trigger_consumer_attr_group = {
380	.name = "trigger",
381	.attrs = iio_trigger_consumer_attrs,
382};
383
384static void iio_trig_release(struct device *device)
385{
386	struct iio_trigger *trig = to_iio_trigger(device);
387	int i;
388
389	if (trig->subirq_base) {
390		for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
391			irq_modify_status(trig->subirq_base + i,
392					  IRQ_NOAUTOEN,
393					  IRQ_NOREQUEST | IRQ_NOPROBE);
394			irq_set_chip(trig->subirq_base + i,
395				     NULL);
396			irq_set_handler(trig->subirq_base + i,
397					NULL);
398		}
399
400		irq_free_descs(trig->subirq_base,
401			       CONFIG_IIO_CONSUMERS_PER_TRIGGER);
402	}
403	kfree(trig->name);
404	kfree(trig);
405}
406
407static struct device_type iio_trig_type = {
408	.release = iio_trig_release,
409};
410
411static void iio_trig_subirqmask(struct irq_data *d)
412{
413	struct irq_chip *chip = irq_data_get_irq_chip(d);
414	struct iio_trigger *trig
415		= container_of(chip,
416			       struct iio_trigger, subirq_chip);
417	trig->subirqs[d->irq - trig->subirq_base].enabled = false;
418}
419
420static void iio_trig_subirqunmask(struct irq_data *d)
421{
422	struct irq_chip *chip = irq_data_get_irq_chip(d);
423	struct iio_trigger *trig
424		= container_of(chip,
425			       struct iio_trigger, subirq_chip);
426	trig->subirqs[d->irq - trig->subirq_base].enabled = true;
427}
428
429struct iio_trigger *iio_allocate_trigger(const char *fmt, ...)
430{
431	va_list vargs;
432	struct iio_trigger *trig;
433	trig = kzalloc(sizeof *trig, GFP_KERNEL);
434	if (trig) {
435		int i;
436		trig->dev.type = &iio_trig_type;
437		trig->dev.bus = &iio_bus_type;
438		device_initialize(&trig->dev);
439		dev_set_drvdata(&trig->dev, (void *)trig);
440
441		mutex_init(&trig->pool_lock);
442		trig->subirq_base
443			= irq_alloc_descs(-1, 0,
444					  CONFIG_IIO_CONSUMERS_PER_TRIGGER,
445					  0);
446		if (trig->subirq_base < 0) {
447			kfree(trig);
448			return NULL;
449		}
450		va_start(vargs, fmt);
451		trig->name = kvasprintf(GFP_KERNEL, fmt, vargs);
452		va_end(vargs);
453		if (trig->name == NULL) {
454			irq_free_descs(trig->subirq_base,
455				       CONFIG_IIO_CONSUMERS_PER_TRIGGER);
456			kfree(trig);
457			return NULL;
458		}
459		trig->subirq_chip.name = trig->name;
460		trig->subirq_chip.irq_mask = &iio_trig_subirqmask;
461		trig->subirq_chip.irq_unmask = &iio_trig_subirqunmask;
462		for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
463			irq_set_chip(trig->subirq_base + i,
464				     &trig->subirq_chip);
465			irq_set_handler(trig->subirq_base + i,
466					&handle_simple_irq);
467			irq_modify_status(trig->subirq_base + i,
468					  IRQ_NOREQUEST | IRQ_NOAUTOEN,
469					  IRQ_NOPROBE);
470		}
471		get_device(&trig->dev);
472	}
473	return trig;
474}
475EXPORT_SYMBOL(iio_allocate_trigger);
476
477void iio_free_trigger(struct iio_trigger *trig)
478{
479	if (trig)
480		put_device(&trig->dev);
481}
482EXPORT_SYMBOL(iio_free_trigger);
483
484void iio_device_register_trigger_consumer(struct iio_dev *indio_dev)
485{
486	indio_dev->groups[indio_dev->groupcounter++] =
487		&iio_trigger_consumer_attr_group;
488}
489
490void iio_device_unregister_trigger_consumer(struct iio_dev *indio_dev)
491{
492	/* Clean up and associated but not attached triggers references */
493	if (indio_dev->trig)
494		iio_put_trigger(indio_dev->trig);
495}
496
497int iio_triggered_buffer_postenable(struct iio_dev *indio_dev)
498{
499	return iio_trigger_attach_poll_func(indio_dev->trig,
500					    indio_dev->pollfunc);
501}
502EXPORT_SYMBOL(iio_triggered_buffer_postenable);
503
504int iio_triggered_buffer_predisable(struct iio_dev *indio_dev)
505{
506	return iio_trigger_dettach_poll_func(indio_dev->trig,
507					     indio_dev->pollfunc);
508}
509EXPORT_SYMBOL(iio_triggered_buffer_predisable);
510