Root/drivers/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/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};
58
59static struct attribute_group iio_trig_attr_group = {
60    .attrs = iio_trig_dev_attrs,
61};
62
63static const struct attribute_group *iio_trig_attr_groups[] = {
64    &iio_trig_attr_group,
65    NULL
66};
67
68int iio_trigger_register(struct iio_trigger *trig_info)
69{
70    int ret;
71
72    trig_info->id = ida_simple_get(&iio_trigger_ida, 0, 0, GFP_KERNEL);
73    if (trig_info->id < 0) {
74        ret = trig_info->id;
75        goto error_ret;
76    }
77    /* Set the name used for the sysfs directory etc */
78    dev_set_name(&trig_info->dev, "trigger%ld",
79             (unsigned long) trig_info->id);
80
81    ret = device_add(&trig_info->dev);
82    if (ret)
83        goto error_unregister_id;
84
85    /* Add to list of available triggers held by the IIO core */
86    mutex_lock(&iio_trigger_list_lock);
87    list_add_tail(&trig_info->list, &iio_trigger_list);
88    mutex_unlock(&iio_trigger_list_lock);
89
90    return 0;
91
92error_unregister_id:
93    ida_simple_remove(&iio_trigger_ida, trig_info->id);
94error_ret:
95    return ret;
96}
97EXPORT_SYMBOL(iio_trigger_register);
98
99void iio_trigger_unregister(struct iio_trigger *trig_info)
100{
101    mutex_lock(&iio_trigger_list_lock);
102    list_del(&trig_info->list);
103    mutex_unlock(&iio_trigger_list_lock);
104
105    ida_simple_remove(&iio_trigger_ida, trig_info->id);
106    /* Possible issue in here */
107    device_unregister(&trig_info->dev);
108}
109EXPORT_SYMBOL(iio_trigger_unregister);
110
111static struct iio_trigger *iio_trigger_find_by_name(const char *name,
112                            size_t len)
113{
114    struct iio_trigger *trig = NULL, *iter;
115
116    mutex_lock(&iio_trigger_list_lock);
117    list_for_each_entry(iter, &iio_trigger_list, list)
118        if (sysfs_streq(iter->name, name)) {
119            trig = iter;
120            break;
121        }
122    mutex_unlock(&iio_trigger_list_lock);
123
124    return trig;
125}
126
127void iio_trigger_poll(struct iio_trigger *trig, s64 time)
128{
129    int i;
130    if (!trig->use_count)
131        for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++)
132            if (trig->subirqs[i].enabled) {
133                trig->use_count++;
134                generic_handle_irq(trig->subirq_base + i);
135            }
136}
137EXPORT_SYMBOL(iio_trigger_poll);
138
139irqreturn_t iio_trigger_generic_data_rdy_poll(int irq, void *private)
140{
141    iio_trigger_poll(private, iio_get_time_ns());
142    return IRQ_HANDLED;
143}
144EXPORT_SYMBOL(iio_trigger_generic_data_rdy_poll);
145
146void iio_trigger_poll_chained(struct iio_trigger *trig, s64 time)
147{
148    int i;
149    if (!trig->use_count)
150        for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++)
151            if (trig->subirqs[i].enabled) {
152                trig->use_count++;
153                handle_nested_irq(trig->subirq_base + i);
154            }
155}
156EXPORT_SYMBOL(iio_trigger_poll_chained);
157
158void iio_trigger_notify_done(struct iio_trigger *trig)
159{
160    trig->use_count--;
161    if (trig->use_count == 0 && trig->ops && trig->ops->try_reenable)
162        if (trig->ops->try_reenable(trig))
163            /* Missed and interrupt so launch new poll now */
164            iio_trigger_poll(trig, 0);
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 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            goto error_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
241error_ret:
242    return ret;
243}
244
245irqreturn_t iio_pollfunc_store_time(int irq, void *p)
246{
247    struct iio_poll_func *pf = p;
248    pf->timestamp = iio_get_time_ns();
249    return IRQ_WAKE_THREAD;
250}
251EXPORT_SYMBOL(iio_pollfunc_store_time);
252
253struct iio_poll_func
254*iio_alloc_pollfunc(irqreturn_t (*h)(int irq, void *p),
255            irqreturn_t (*thread)(int irq, void *p),
256            int type,
257            struct iio_dev *indio_dev,
258            const char *fmt,
259            ...)
260{
261    va_list vargs;
262    struct iio_poll_func *pf;
263
264    pf = kmalloc(sizeof *pf, GFP_KERNEL);
265    if (pf == NULL)
266        return NULL;
267    va_start(vargs, fmt);
268    pf->name = kvasprintf(GFP_KERNEL, fmt, vargs);
269    va_end(vargs);
270    if (pf->name == NULL) {
271        kfree(pf);
272        return NULL;
273    }
274    pf->h = h;
275    pf->thread = thread;
276    pf->type = type;
277    pf->indio_dev = indio_dev;
278
279    return pf;
280}
281EXPORT_SYMBOL_GPL(iio_alloc_pollfunc);
282
283void iio_dealloc_pollfunc(struct iio_poll_func *pf)
284{
285    kfree(pf->name);
286    kfree(pf);
287}
288EXPORT_SYMBOL_GPL(iio_dealloc_pollfunc);
289
290/**
291 * iio_trigger_read_current() - trigger consumer sysfs query which trigger
292 *
293 * For trigger consumers the current_trigger interface allows the trigger
294 * used by the device to be queried.
295 **/
296static ssize_t iio_trigger_read_current(struct device *dev,
297                    struct device_attribute *attr,
298                    char *buf)
299{
300    struct iio_dev *indio_dev = dev_to_iio_dev(dev);
301
302    if (indio_dev->trig)
303        return sprintf(buf, "%s\n", indio_dev->trig->name);
304    return 0;
305}
306
307/**
308 * iio_trigger_write_current() trigger consumer sysfs set current trigger
309 *
310 * For trigger consumers the current_trigger interface allows the trigger
311 * used for this device to be specified at run time based on the triggers
312 * name.
313 **/
314static ssize_t iio_trigger_write_current(struct device *dev,
315                     struct device_attribute *attr,
316                     const char *buf,
317                     size_t len)
318{
319    struct iio_dev *indio_dev = dev_to_iio_dev(dev);
320    struct iio_trigger *oldtrig = indio_dev->trig;
321    struct iio_trigger *trig;
322    int ret;
323
324    mutex_lock(&indio_dev->mlock);
325    if (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED) {
326        mutex_unlock(&indio_dev->mlock);
327        return -EBUSY;
328    }
329    mutex_unlock(&indio_dev->mlock);
330
331    trig = iio_trigger_find_by_name(buf, len);
332    if (oldtrig == trig)
333        return len;
334
335    if (trig && indio_dev->info->validate_trigger) {
336        ret = indio_dev->info->validate_trigger(indio_dev, trig);
337        if (ret)
338            return ret;
339    }
340
341    if (trig && trig->ops && trig->ops->validate_device) {
342        ret = trig->ops->validate_device(trig, indio_dev);
343        if (ret)
344            return ret;
345    }
346
347    indio_dev->trig = trig;
348
349    if (oldtrig && indio_dev->trig != oldtrig)
350        iio_trigger_put(oldtrig);
351    if (indio_dev->trig)
352        iio_trigger_get(indio_dev->trig);
353
354    return len;
355}
356
357static DEVICE_ATTR(current_trigger, S_IRUGO | S_IWUSR,
358           iio_trigger_read_current,
359           iio_trigger_write_current);
360
361static struct attribute *iio_trigger_consumer_attrs[] = {
362    &dev_attr_current_trigger.attr,
363    NULL,
364};
365
366static const struct attribute_group iio_trigger_consumer_attr_group = {
367    .name = "trigger",
368    .attrs = iio_trigger_consumer_attrs,
369};
370
371static void iio_trig_release(struct device *device)
372{
373    struct iio_trigger *trig = to_iio_trigger(device);
374    int i;
375
376    if (trig->subirq_base) {
377        for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
378            irq_modify_status(trig->subirq_base + i,
379                      IRQ_NOAUTOEN,
380                      IRQ_NOREQUEST | IRQ_NOPROBE);
381            irq_set_chip(trig->subirq_base + i,
382                     NULL);
383            irq_set_handler(trig->subirq_base + i,
384                    NULL);
385        }
386
387        irq_free_descs(trig->subirq_base,
388                   CONFIG_IIO_CONSUMERS_PER_TRIGGER);
389    }
390    kfree(trig->name);
391    kfree(trig);
392}
393
394static struct device_type iio_trig_type = {
395    .release = iio_trig_release,
396    .groups = iio_trig_attr_groups,
397};
398
399static void iio_trig_subirqmask(struct irq_data *d)
400{
401    struct irq_chip *chip = irq_data_get_irq_chip(d);
402    struct iio_trigger *trig
403        = container_of(chip,
404                   struct iio_trigger, subirq_chip);
405    trig->subirqs[d->irq - trig->subirq_base].enabled = false;
406}
407
408static void iio_trig_subirqunmask(struct irq_data *d)
409{
410    struct irq_chip *chip = irq_data_get_irq_chip(d);
411    struct iio_trigger *trig
412        = container_of(chip,
413                   struct iio_trigger, subirq_chip);
414    trig->subirqs[d->irq - trig->subirq_base].enabled = true;
415}
416
417struct iio_trigger *iio_trigger_alloc(const char *fmt, ...)
418{
419    va_list vargs;
420    struct iio_trigger *trig;
421    trig = kzalloc(sizeof *trig, GFP_KERNEL);
422    if (trig) {
423        int i;
424        trig->dev.type = &iio_trig_type;
425        trig->dev.bus = &iio_bus_type;
426        device_initialize(&trig->dev);
427
428        mutex_init(&trig->pool_lock);
429        trig->subirq_base
430            = irq_alloc_descs(-1, 0,
431                      CONFIG_IIO_CONSUMERS_PER_TRIGGER,
432                      0);
433        if (trig->subirq_base < 0) {
434            kfree(trig);
435            return NULL;
436        }
437        va_start(vargs, fmt);
438        trig->name = kvasprintf(GFP_KERNEL, fmt, vargs);
439        va_end(vargs);
440        if (trig->name == NULL) {
441            irq_free_descs(trig->subirq_base,
442                       CONFIG_IIO_CONSUMERS_PER_TRIGGER);
443            kfree(trig);
444            return NULL;
445        }
446        trig->subirq_chip.name = trig->name;
447        trig->subirq_chip.irq_mask = &iio_trig_subirqmask;
448        trig->subirq_chip.irq_unmask = &iio_trig_subirqunmask;
449        for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
450            irq_set_chip(trig->subirq_base + i,
451                     &trig->subirq_chip);
452            irq_set_handler(trig->subirq_base + i,
453                    &handle_simple_irq);
454            irq_modify_status(trig->subirq_base + i,
455                      IRQ_NOREQUEST | IRQ_NOAUTOEN,
456                      IRQ_NOPROBE);
457        }
458        get_device(&trig->dev);
459    }
460    return trig;
461}
462EXPORT_SYMBOL(iio_trigger_alloc);
463
464void iio_trigger_free(struct iio_trigger *trig)
465{
466    if (trig)
467        put_device(&trig->dev);
468}
469EXPORT_SYMBOL(iio_trigger_free);
470
471void iio_device_register_trigger_consumer(struct iio_dev *indio_dev)
472{
473    indio_dev->groups[indio_dev->groupcounter++] =
474        &iio_trigger_consumer_attr_group;
475}
476
477void iio_device_unregister_trigger_consumer(struct iio_dev *indio_dev)
478{
479    /* Clean up and associated but not attached triggers references */
480    if (indio_dev->trig)
481        iio_trigger_put(indio_dev->trig);
482}
483
484int iio_triggered_buffer_postenable(struct iio_dev *indio_dev)
485{
486    return iio_trigger_attach_poll_func(indio_dev->trig,
487                        indio_dev->pollfunc);
488}
489EXPORT_SYMBOL(iio_triggered_buffer_postenable);
490
491int iio_triggered_buffer_predisable(struct iio_dev *indio_dev)
492{
493    return iio_trigger_detach_poll_func(indio_dev->trig,
494                         indio_dev->pollfunc);
495}
496EXPORT_SYMBOL(iio_triggered_buffer_predisable);
497

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