1// SPDX-License-Identifier: GPL-2.0-only
2/* Industrial I/O event handling
3 *
4 * Copyright (c) 2008 Jonathan Cameron
5 *
6 * Based on elements of hwmon and input subsystems.
7 */
8
9#include <linux/anon_inodes.h>
10#include <linux/device.h>
11#include <linux/fs.h>
12#include <linux/kernel.h>
13#include <linux/kfifo.h>
14#include <linux/module.h>
15#include <linux/poll.h>
16#include <linux/sched.h>
17#include <linux/slab.h>
18#include <linux/uaccess.h>
19#include <linux/wait.h>
20#include <linux/iio/iio.h>
21#include <linux/iio/iio-opaque.h>
22#include "iio_core.h"
23#include <linux/iio/sysfs.h>
24#include <linux/iio/events.h>
25
26/**
27 * struct iio_event_interface - chrdev interface for an event line
28 * @wait: wait queue to allow blocking reads of events
29 * @det_events: list of detected events
30 * @dev_attr_list: list of event interface sysfs attribute
31 * @flags: file operations related flags including busy flag.
32 * @group: event interface sysfs attribute group
33 * @read_lock: lock to protect kfifo read operations
34 * @ioctl_handler: handler for event ioctl() calls
35 */
36struct iio_event_interface {
37 wait_queue_head_t wait;
38 DECLARE_KFIFO(det_events, struct iio_event_data, 16);
39
40 struct list_head dev_attr_list;
41 unsigned long flags;
42 struct attribute_group group;
43 struct mutex read_lock;
44 struct iio_ioctl_handler ioctl_handler;
45};
46
47bool iio_event_enabled(const struct iio_event_interface *ev_int)
48{
49 return !!test_bit(IIO_BUSY_BIT_POS, &ev_int->flags);
50}
51
52/**
53 * iio_push_event() - try to add event to the list for userspace reading
54 * @indio_dev: IIO device structure
55 * @ev_code: What event
56 * @timestamp: When the event occurred
57 *
58 * Note: The caller must make sure that this function is not running
59 * concurrently for the same indio_dev more than once.
60 *
61 * This function may be safely used as soon as a valid reference to iio_dev has
62 * been obtained via iio_device_alloc(), but any events that are submitted
63 * before iio_device_register() has successfully completed will be silently
64 * discarded.
65 **/
66int iio_push_event(struct iio_dev *indio_dev, u64 ev_code, s64 timestamp)
67{
68 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
69 struct iio_event_interface *ev_int = iio_dev_opaque->event_interface;
70 struct iio_event_data ev;
71 int copied;
72
73 if (!ev_int)
74 return 0;
75
76 /* Does anyone care? */
77 if (iio_event_enabled(ev_int)) {
78
79 ev.id = ev_code;
80 ev.timestamp = timestamp;
81
82 copied = kfifo_put(&ev_int->det_events, ev);
83 if (copied != 0)
84 wake_up_poll(&ev_int->wait, EPOLLIN);
85 }
86
87 return 0;
88}
89EXPORT_SYMBOL(iio_push_event);
90
91/**
92 * iio_event_poll() - poll the event queue to find out if it has data
93 * @filep: File structure pointer to identify the device
94 * @wait: Poll table pointer to add the wait queue on
95 *
96 * Return: (EPOLLIN | EPOLLRDNORM) if data is available for reading
97 * or a negative error code on failure
98 */
99static __poll_t iio_event_poll(struct file *filep,
100 struct poll_table_struct *wait)
101{
102 struct iio_dev *indio_dev = filep->private_data;
103 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
104 struct iio_event_interface *ev_int = iio_dev_opaque->event_interface;
105 __poll_t events = 0;
106
107 if (!indio_dev->info)
108 return events;
109
110 poll_wait(filp: filep, wait_address: &ev_int->wait, p: wait);
111
112 if (!kfifo_is_empty(&ev_int->det_events))
113 events = EPOLLIN | EPOLLRDNORM;
114
115 return events;
116}
117
118static ssize_t iio_event_chrdev_read(struct file *filep,
119 char __user *buf,
120 size_t count,
121 loff_t *f_ps)
122{
123 struct iio_dev *indio_dev = filep->private_data;
124 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
125 struct iio_event_interface *ev_int = iio_dev_opaque->event_interface;
126 unsigned int copied;
127 int ret;
128
129 if (!indio_dev->info)
130 return -ENODEV;
131
132 if (count < sizeof(struct iio_event_data))
133 return -EINVAL;
134
135 do {
136 if (kfifo_is_empty(&ev_int->det_events)) {
137 if (filep->f_flags & O_NONBLOCK)
138 return -EAGAIN;
139
140 ret = wait_event_interruptible(ev_int->wait,
141 !kfifo_is_empty(&ev_int->det_events) ||
142 indio_dev->info == NULL);
143 if (ret)
144 return ret;
145 if (indio_dev->info == NULL)
146 return -ENODEV;
147 }
148
149 if (mutex_lock_interruptible(&ev_int->read_lock))
150 return -ERESTARTSYS;
151 ret = kfifo_to_user(&ev_int->det_events, buf, count, &copied);
152 mutex_unlock(lock: &ev_int->read_lock);
153
154 if (ret)
155 return ret;
156
157 /*
158 * If we couldn't read anything from the fifo (a different
159 * thread might have been faster) we either return -EAGAIN if
160 * the file descriptor is non-blocking, otherwise we go back to
161 * sleep and wait for more data to arrive.
162 */
163 if (copied == 0 && (filep->f_flags & O_NONBLOCK))
164 return -EAGAIN;
165
166 } while (copied == 0);
167
168 return copied;
169}
170
171static int iio_event_chrdev_release(struct inode *inode, struct file *filep)
172{
173 struct iio_dev *indio_dev = filep->private_data;
174 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
175 struct iio_event_interface *ev_int = iio_dev_opaque->event_interface;
176
177 clear_bit(IIO_BUSY_BIT_POS, addr: &ev_int->flags);
178
179 iio_device_put(indio_dev);
180
181 return 0;
182}
183
184static const struct file_operations iio_event_chrdev_fileops = {
185 .read = iio_event_chrdev_read,
186 .poll = iio_event_poll,
187 .release = iio_event_chrdev_release,
188 .owner = THIS_MODULE,
189 .llseek = noop_llseek,
190};
191
192static int iio_event_getfd(struct iio_dev *indio_dev)
193{
194 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
195 struct iio_event_interface *ev_int = iio_dev_opaque->event_interface;
196 int fd;
197
198 if (ev_int == NULL)
199 return -ENODEV;
200
201 fd = mutex_lock_interruptible(&iio_dev_opaque->mlock);
202 if (fd)
203 return fd;
204
205 if (test_and_set_bit(IIO_BUSY_BIT_POS, addr: &ev_int->flags)) {
206 fd = -EBUSY;
207 goto unlock;
208 }
209
210 iio_device_get(indio_dev);
211
212 fd = anon_inode_getfd(name: "iio:event", fops: &iio_event_chrdev_fileops,
213 priv: indio_dev, O_RDONLY | O_CLOEXEC);
214 if (fd < 0) {
215 clear_bit(IIO_BUSY_BIT_POS, addr: &ev_int->flags);
216 iio_device_put(indio_dev);
217 } else {
218 kfifo_reset_out(&ev_int->det_events);
219 }
220
221unlock:
222 mutex_unlock(lock: &iio_dev_opaque->mlock);
223 return fd;
224}
225
226static const char * const iio_ev_type_text[] = {
227 [IIO_EV_TYPE_THRESH] = "thresh",
228 [IIO_EV_TYPE_MAG] = "mag",
229 [IIO_EV_TYPE_ROC] = "roc",
230 [IIO_EV_TYPE_THRESH_ADAPTIVE] = "thresh_adaptive",
231 [IIO_EV_TYPE_MAG_ADAPTIVE] = "mag_adaptive",
232 [IIO_EV_TYPE_CHANGE] = "change",
233 [IIO_EV_TYPE_MAG_REFERENCED] = "mag_referenced",
234 [IIO_EV_TYPE_GESTURE] = "gesture",
235};
236
237static const char * const iio_ev_dir_text[] = {
238 [IIO_EV_DIR_EITHER] = "either",
239 [IIO_EV_DIR_RISING] = "rising",
240 [IIO_EV_DIR_FALLING] = "falling",
241 [IIO_EV_DIR_SINGLETAP] = "singletap",
242 [IIO_EV_DIR_DOUBLETAP] = "doubletap",
243};
244
245static const char * const iio_ev_info_text[] = {
246 [IIO_EV_INFO_ENABLE] = "en",
247 [IIO_EV_INFO_VALUE] = "value",
248 [IIO_EV_INFO_HYSTERESIS] = "hysteresis",
249 [IIO_EV_INFO_PERIOD] = "period",
250 [IIO_EV_INFO_HIGH_PASS_FILTER_3DB] = "high_pass_filter_3db",
251 [IIO_EV_INFO_LOW_PASS_FILTER_3DB] = "low_pass_filter_3db",
252 [IIO_EV_INFO_TIMEOUT] = "timeout",
253 [IIO_EV_INFO_RESET_TIMEOUT] = "reset_timeout",
254 [IIO_EV_INFO_TAP2_MIN_DELAY] = "tap2_min_delay",
255 [IIO_EV_INFO_RUNNING_PERIOD] = "runningperiod",
256 [IIO_EV_INFO_RUNNING_COUNT] = "runningcount",
257};
258
259static enum iio_event_direction iio_ev_attr_dir(struct iio_dev_attr *attr)
260{
261 return attr->c->event_spec[attr->address & 0xffff].dir;
262}
263
264static enum iio_event_type iio_ev_attr_type(struct iio_dev_attr *attr)
265{
266 return attr->c->event_spec[attr->address & 0xffff].type;
267}
268
269static enum iio_event_info iio_ev_attr_info(struct iio_dev_attr *attr)
270{
271 return (attr->address >> 16) & 0xffff;
272}
273
274static ssize_t iio_ev_state_store(struct device *dev,
275 struct device_attribute *attr,
276 const char *buf,
277 size_t len)
278{
279 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
280 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
281 int ret;
282 bool val;
283
284 ret = kstrtobool(s: buf, res: &val);
285 if (ret < 0)
286 return ret;
287
288 ret = indio_dev->info->write_event_config(indio_dev,
289 this_attr->c, iio_ev_attr_type(attr: this_attr),
290 iio_ev_attr_dir(attr: this_attr), val);
291
292 return (ret < 0) ? ret : len;
293}
294
295static ssize_t iio_ev_state_show(struct device *dev,
296 struct device_attribute *attr,
297 char *buf)
298{
299 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
300 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
301 int val;
302
303 val = indio_dev->info->read_event_config(indio_dev,
304 this_attr->c, iio_ev_attr_type(attr: this_attr),
305 iio_ev_attr_dir(attr: this_attr));
306 if (val < 0)
307 return val;
308 else
309 return sysfs_emit(buf, fmt: "%d\n", val);
310}
311
312static ssize_t iio_ev_value_show(struct device *dev,
313 struct device_attribute *attr,
314 char *buf)
315{
316 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
317 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
318 int val, val2, val_arr[2];
319 int ret;
320
321 ret = indio_dev->info->read_event_value(indio_dev,
322 this_attr->c, iio_ev_attr_type(attr: this_attr),
323 iio_ev_attr_dir(attr: this_attr), iio_ev_attr_info(attr: this_attr),
324 &val, &val2);
325 if (ret < 0)
326 return ret;
327 val_arr[0] = val;
328 val_arr[1] = val2;
329 return iio_format_value(buf, type: ret, size: 2, vals: val_arr);
330}
331
332static ssize_t iio_ev_value_store(struct device *dev,
333 struct device_attribute *attr,
334 const char *buf,
335 size_t len)
336{
337 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
338 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
339 int val, val2;
340 int ret;
341
342 if (!indio_dev->info->write_event_value)
343 return -EINVAL;
344
345 ret = iio_str_to_fixpoint(str: buf, fract_mult: 100000, integer: &val, fract: &val2);
346 if (ret)
347 return ret;
348 ret = indio_dev->info->write_event_value(indio_dev,
349 this_attr->c, iio_ev_attr_type(attr: this_attr),
350 iio_ev_attr_dir(attr: this_attr), iio_ev_attr_info(attr: this_attr),
351 val, val2);
352 if (ret < 0)
353 return ret;
354
355 return len;
356}
357
358static ssize_t iio_ev_label_show(struct device *dev,
359 struct device_attribute *attr,
360 char *buf)
361{
362 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
363 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
364
365 if (indio_dev->info->read_event_label)
366 return indio_dev->info->read_event_label(indio_dev,
367 this_attr->c, iio_ev_attr_type(attr: this_attr),
368 iio_ev_attr_dir(attr: this_attr), buf);
369
370 return -EINVAL;
371}
372
373static int iio_device_add_event(struct iio_dev *indio_dev,
374 const struct iio_chan_spec *chan, unsigned int spec_index,
375 enum iio_event_type type, enum iio_event_direction dir,
376 enum iio_shared_by shared_by, const unsigned long *mask)
377{
378 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
379 ssize_t (*show)(struct device *dev, struct device_attribute *attr,
380 char *buf);
381 ssize_t (*store)(struct device *dev, struct device_attribute *attr,
382 const char *buf, size_t len);
383 unsigned int attrcount = 0;
384 unsigned int i;
385 char *postfix;
386 int ret;
387
388 for_each_set_bit(i, mask, sizeof(*mask)*8) {
389 if (i >= ARRAY_SIZE(iio_ev_info_text))
390 return -EINVAL;
391 if (dir != IIO_EV_DIR_NONE)
392 postfix = kasprintf(GFP_KERNEL, fmt: "%s_%s_%s",
393 iio_ev_type_text[type],
394 iio_ev_dir_text[dir],
395 iio_ev_info_text[i]);
396 else
397 postfix = kasprintf(GFP_KERNEL, fmt: "%s_%s",
398 iio_ev_type_text[type],
399 iio_ev_info_text[i]);
400 if (postfix == NULL)
401 return -ENOMEM;
402
403 if (i == IIO_EV_INFO_ENABLE) {
404 show = iio_ev_state_show;
405 store = iio_ev_state_store;
406 } else {
407 show = iio_ev_value_show;
408 store = iio_ev_value_store;
409 }
410
411 ret = __iio_add_chan_devattr(postfix, chan, func: show, writefunc: store,
412 mask: (i << 16) | spec_index, shared_by, dev: &indio_dev->dev,
413 NULL,
414 attr_list: &iio_dev_opaque->event_interface->dev_attr_list);
415 kfree(objp: postfix);
416
417 if ((ret == -EBUSY) && (shared_by != IIO_SEPARATE))
418 continue;
419
420 if (ret)
421 return ret;
422
423 attrcount++;
424 }
425
426 return attrcount;
427}
428
429static int iio_device_add_event_label(struct iio_dev *indio_dev,
430 const struct iio_chan_spec *chan,
431 unsigned int spec_index,
432 enum iio_event_type type,
433 enum iio_event_direction dir)
434{
435 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
436 char *postfix;
437 int ret;
438
439 if (!indio_dev->info->read_event_label)
440 return 0;
441
442 if (dir != IIO_EV_DIR_NONE)
443 postfix = kasprintf(GFP_KERNEL, fmt: "%s_%s_label",
444 iio_ev_type_text[type],
445 iio_ev_dir_text[dir]);
446 else
447 postfix = kasprintf(GFP_KERNEL, fmt: "%s_label",
448 iio_ev_type_text[type]);
449 if (postfix == NULL)
450 return -ENOMEM;
451
452 ret = __iio_add_chan_devattr(postfix, chan, func: &iio_ev_label_show, NULL,
453 mask: spec_index, shared_by: IIO_SEPARATE, dev: &indio_dev->dev, NULL,
454 attr_list: &iio_dev_opaque->event_interface->dev_attr_list);
455
456 kfree(objp: postfix);
457
458 if (ret < 0)
459 return ret;
460
461 return 1;
462}
463
464static int iio_device_add_event_sysfs(struct iio_dev *indio_dev,
465 struct iio_chan_spec const *chan)
466{
467 int ret = 0, i, attrcount = 0;
468 enum iio_event_direction dir;
469 enum iio_event_type type;
470
471 for (i = 0; i < chan->num_event_specs; i++) {
472 type = chan->event_spec[i].type;
473 dir = chan->event_spec[i].dir;
474
475 ret = iio_device_add_event(indio_dev, chan, spec_index: i, type, dir,
476 shared_by: IIO_SEPARATE, mask: &chan->event_spec[i].mask_separate);
477 if (ret < 0)
478 return ret;
479 attrcount += ret;
480
481 ret = iio_device_add_event(indio_dev, chan, spec_index: i, type, dir,
482 shared_by: IIO_SHARED_BY_TYPE,
483 mask: &chan->event_spec[i].mask_shared_by_type);
484 if (ret < 0)
485 return ret;
486 attrcount += ret;
487
488 ret = iio_device_add_event(indio_dev, chan, spec_index: i, type, dir,
489 shared_by: IIO_SHARED_BY_DIR,
490 mask: &chan->event_spec[i].mask_shared_by_dir);
491 if (ret < 0)
492 return ret;
493 attrcount += ret;
494
495 ret = iio_device_add_event(indio_dev, chan, spec_index: i, type, dir,
496 shared_by: IIO_SHARED_BY_ALL,
497 mask: &chan->event_spec[i].mask_shared_by_all);
498 if (ret < 0)
499 return ret;
500 attrcount += ret;
501
502 ret = iio_device_add_event_label(indio_dev, chan, spec_index: i, type, dir);
503 if (ret < 0)
504 return ret;
505 attrcount += ret;
506 }
507 ret = attrcount;
508 return ret;
509}
510
511static inline int __iio_add_event_config_attrs(struct iio_dev *indio_dev)
512{
513 int j, ret, attrcount = 0;
514
515 /* Dynamically created from the channels array */
516 for (j = 0; j < indio_dev->num_channels; j++) {
517 ret = iio_device_add_event_sysfs(indio_dev,
518 chan: &indio_dev->channels[j]);
519 if (ret < 0)
520 return ret;
521 attrcount += ret;
522 }
523 return attrcount;
524}
525
526static bool iio_check_for_dynamic_events(struct iio_dev *indio_dev)
527{
528 int j;
529
530 for (j = 0; j < indio_dev->num_channels; j++) {
531 if (indio_dev->channels[j].num_event_specs != 0)
532 return true;
533 }
534 return false;
535}
536
537static void iio_setup_ev_int(struct iio_event_interface *ev_int)
538{
539 INIT_KFIFO(ev_int->det_events);
540 init_waitqueue_head(&ev_int->wait);
541 mutex_init(&ev_int->read_lock);
542}
543
544static long iio_event_ioctl(struct iio_dev *indio_dev, struct file *filp,
545 unsigned int cmd, unsigned long arg)
546{
547 int __user *ip = (int __user *)arg;
548 int fd;
549
550 if (cmd == IIO_GET_EVENT_FD_IOCTL) {
551 fd = iio_event_getfd(indio_dev);
552 if (fd < 0)
553 return fd;
554 if (copy_to_user(to: ip, from: &fd, n: sizeof(fd)))
555 return -EFAULT;
556 return 0;
557 }
558
559 return IIO_IOCTL_UNHANDLED;
560}
561
562static const char *iio_event_group_name = "events";
563int iio_device_register_eventset(struct iio_dev *indio_dev)
564{
565 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
566 struct iio_event_interface *ev_int;
567 struct iio_dev_attr *p;
568 int ret = 0, attrcount_orig = 0, attrcount, attrn;
569 struct attribute **attr;
570
571 if (!(indio_dev->info->event_attrs ||
572 iio_check_for_dynamic_events(indio_dev)))
573 return 0;
574
575 ev_int = kzalloc(size: sizeof(struct iio_event_interface), GFP_KERNEL);
576 if (ev_int == NULL)
577 return -ENOMEM;
578
579 iio_dev_opaque->event_interface = ev_int;
580
581 INIT_LIST_HEAD(list: &ev_int->dev_attr_list);
582
583 iio_setup_ev_int(ev_int);
584 if (indio_dev->info->event_attrs != NULL) {
585 attr = indio_dev->info->event_attrs->attrs;
586 while (*attr++ != NULL)
587 attrcount_orig++;
588 }
589 attrcount = attrcount_orig;
590 if (indio_dev->channels) {
591 ret = __iio_add_event_config_attrs(indio_dev);
592 if (ret < 0)
593 goto error_free_setup_event_lines;
594 attrcount += ret;
595 }
596
597 ev_int->group.name = iio_event_group_name;
598 ev_int->group.attrs = kcalloc(n: attrcount + 1,
599 size: sizeof(ev_int->group.attrs[0]),
600 GFP_KERNEL);
601 if (ev_int->group.attrs == NULL) {
602 ret = -ENOMEM;
603 goto error_free_setup_event_lines;
604 }
605 if (indio_dev->info->event_attrs)
606 memcpy(ev_int->group.attrs,
607 indio_dev->info->event_attrs->attrs,
608 sizeof(ev_int->group.attrs[0]) * attrcount_orig);
609 attrn = attrcount_orig;
610 /* Add all elements from the list. */
611 list_for_each_entry(p, &ev_int->dev_attr_list, l)
612 ev_int->group.attrs[attrn++] = &p->dev_attr.attr;
613
614 ret = iio_device_register_sysfs_group(indio_dev, group: &ev_int->group);
615 if (ret)
616 goto error_free_group_attrs;
617
618 ev_int->ioctl_handler.ioctl = iio_event_ioctl;
619 iio_device_ioctl_handler_register(indio_dev: &iio_dev_opaque->indio_dev,
620 h: &ev_int->ioctl_handler);
621
622 return 0;
623
624error_free_group_attrs:
625 kfree(objp: ev_int->group.attrs);
626error_free_setup_event_lines:
627 iio_free_chan_devattr_list(attr_list: &ev_int->dev_attr_list);
628 kfree(objp: ev_int);
629 iio_dev_opaque->event_interface = NULL;
630 return ret;
631}
632
633/**
634 * iio_device_wakeup_eventset - Wakes up the event waitqueue
635 * @indio_dev: The IIO device
636 *
637 * Wakes up the event waitqueue used for poll() and blocking read().
638 * Should usually be called when the device is unregistered.
639 */
640void iio_device_wakeup_eventset(struct iio_dev *indio_dev)
641{
642 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
643
644 if (iio_dev_opaque->event_interface == NULL)
645 return;
646 wake_up(&iio_dev_opaque->event_interface->wait);
647}
648
649void iio_device_unregister_eventset(struct iio_dev *indio_dev)
650{
651 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
652 struct iio_event_interface *ev_int = iio_dev_opaque->event_interface;
653
654 if (ev_int == NULL)
655 return;
656
657 iio_device_ioctl_handler_unregister(h: &ev_int->ioctl_handler);
658 iio_free_chan_devattr_list(attr_list: &ev_int->dev_attr_list);
659 kfree(objp: ev_int->group.attrs);
660 kfree(objp: ev_int);
661 iio_dev_opaque->event_interface = NULL;
662}
663

source code of linux/drivers/iio/industrialio-event.c