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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 */
35struct iio_event_interface {
36 wait_queue_head_t wait;
37 DECLARE_KFIFO(det_events, struct iio_event_data, 16);
38
39 struct list_head dev_attr_list;
40 unsigned long flags;
41 struct attribute_group group;
42 struct mutex read_lock;
43};
44
45bool iio_event_enabled(const struct iio_event_interface *ev_int)
46{
47 return !!test_bit(IIO_BUSY_BIT_POS, &ev_int->flags);
48}
49
50/**
51 * iio_push_event() - try to add event to the list for userspace reading
52 * @indio_dev: IIO device structure
53 * @ev_code: What event
54 * @timestamp: When the event occurred
55 *
56 * Note: The caller must make sure that this function is not running
57 * concurrently for the same indio_dev more than once.
58 *
59 * This function may be safely used as soon as a valid reference to iio_dev has
60 * been obtained via iio_device_alloc(), but any events that are submitted
61 * before iio_device_register() has successfully completed will be silently
62 * discarded.
63 **/
64int iio_push_event(struct iio_dev *indio_dev, u64 ev_code, s64 timestamp)
65{
66 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
67 struct iio_event_interface *ev_int = iio_dev_opaque->event_interface;
68 struct iio_event_data ev;
69 int copied;
70
71 if (!ev_int)
72 return 0;
73
74 /* Does anyone care? */
75 if (iio_event_enabled(ev_int)) {
76
77 ev.id = ev_code;
78 ev.timestamp = timestamp;
79
80 copied = kfifo_put(&ev_int->det_events, ev);
81 if (copied != 0)
82 wake_up_poll(&ev_int->wait, EPOLLIN);
83 }
84
85 return 0;
86}
87EXPORT_SYMBOL(iio_push_event);
88
89/**
90 * iio_event_poll() - poll the event queue to find out if it has data
91 * @filep: File structure pointer to identify the device
92 * @wait: Poll table pointer to add the wait queue on
93 *
94 * Return: (EPOLLIN | EPOLLRDNORM) if data is available for reading
95 * or a negative error code on failure
96 */
97static __poll_t iio_event_poll(struct file *filep,
98 struct poll_table_struct *wait)
99{
100 struct iio_dev *indio_dev = filep->private_data;
101 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
102 struct iio_event_interface *ev_int = iio_dev_opaque->event_interface;
103 __poll_t events = 0;
104
105 if (!indio_dev->info)
106 return events;
107
108 poll_wait(filep, &ev_int->wait, wait);
109
110 if (!kfifo_is_empty(&ev_int->det_events))
111 events = EPOLLIN | EPOLLRDNORM;
112
113 return events;
114}
115
116static ssize_t iio_event_chrdev_read(struct file *filep,
117 char __user *buf,
118 size_t count,
119 loff_t *f_ps)
120{
121 struct iio_dev *indio_dev = filep->private_data;
122 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
123 struct iio_event_interface *ev_int = iio_dev_opaque->event_interface;
124 unsigned int copied;
125 int ret;
126
127 if (!indio_dev->info)
128 return -ENODEV;
129
130 if (count < sizeof(struct iio_event_data))
131 return -EINVAL;
132
133 do {
134 if (kfifo_is_empty(&ev_int->det_events)) {
135 if (filep->f_flags & O_NONBLOCK)
136 return -EAGAIN;
137
138 ret = wait_event_interruptible(ev_int->wait,
139 !kfifo_is_empty(&ev_int->det_events) ||
140 indio_dev->info == NULL);
141 if (ret)
142 return ret;
143 if (indio_dev->info == NULL)
144 return -ENODEV;
145 }
146
147 if (mutex_lock_interruptible(&ev_int->read_lock))
148 return -ERESTARTSYS;
149 ret = kfifo_to_user(&ev_int->det_events, buf, count, &copied);
150 mutex_unlock(&ev_int->read_lock);
151
152 if (ret)
153 return ret;
154
155 /*
156 * If we couldn't read anything from the fifo (a different
157 * thread might have been faster) we either return -EAGAIN if
158 * the file descriptor is non-blocking, otherwise we go back to
159 * sleep and wait for more data to arrive.
160 */
161 if (copied == 0 && (filep->f_flags & O_NONBLOCK))
162 return -EAGAIN;
163
164 } while (copied == 0);
165
166 return copied;
167}
168
169static int iio_event_chrdev_release(struct inode *inode, struct file *filep)
170{
171 struct iio_dev *indio_dev = filep->private_data;
172 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
173 struct iio_event_interface *ev_int = iio_dev_opaque->event_interface;
174
175 clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags);
176
177 iio_device_put(indio_dev);
178
179 return 0;
180}
181
182static const struct file_operations iio_event_chrdev_fileops = {
183 .read = iio_event_chrdev_read,
184 .poll = iio_event_poll,
185 .release = iio_event_chrdev_release,
186 .owner = THIS_MODULE,
187 .llseek = noop_llseek,
188};
189
190int iio_event_getfd(struct iio_dev *indio_dev)
191{
192 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
193 struct iio_event_interface *ev_int = iio_dev_opaque->event_interface;
194 int fd;
195
196 if (ev_int == NULL)
197 return -ENODEV;
198
199 fd = mutex_lock_interruptible(&indio_dev->mlock);
200 if (fd)
201 return fd;
202
203 if (test_and_set_bit(IIO_BUSY_BIT_POS, &ev_int->flags)) {
204 fd = -EBUSY;
205 goto unlock;
206 }
207
208 iio_device_get(indio_dev);
209
210 fd = anon_inode_getfd("iio:event", &iio_event_chrdev_fileops,
211 indio_dev, O_RDONLY | O_CLOEXEC);
212 if (fd < 0) {
213 clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags);
214 iio_device_put(indio_dev);
215 } else {
216 kfifo_reset_out(&ev_int->det_events);
217 }
218
219unlock:
220 mutex_unlock(&indio_dev->mlock);
221 return fd;
222}
223
224static const char * const iio_ev_type_text[] = {
225 [IIO_EV_TYPE_THRESH] = "thresh",
226 [IIO_EV_TYPE_MAG] = "mag",
227 [IIO_EV_TYPE_ROC] = "roc",
228 [IIO_EV_TYPE_THRESH_ADAPTIVE] = "thresh_adaptive",
229 [IIO_EV_TYPE_MAG_ADAPTIVE] = "mag_adaptive",
230 [IIO_EV_TYPE_CHANGE] = "change",
231};
232
233static const char * const iio_ev_dir_text[] = {
234 [IIO_EV_DIR_EITHER] = "either",
235 [IIO_EV_DIR_RISING] = "rising",
236 [IIO_EV_DIR_FALLING] = "falling"
237};
238
239static const char * const iio_ev_info_text[] = {
240 [IIO_EV_INFO_ENABLE] = "en",
241 [IIO_EV_INFO_VALUE] = "value",
242 [IIO_EV_INFO_HYSTERESIS] = "hysteresis",
243 [IIO_EV_INFO_PERIOD] = "period",
244 [IIO_EV_INFO_HIGH_PASS_FILTER_3DB] = "high_pass_filter_3db",
245 [IIO_EV_INFO_LOW_PASS_FILTER_3DB] = "low_pass_filter_3db",
246};
247
248static enum iio_event_direction iio_ev_attr_dir(struct iio_dev_attr *attr)
249{
250 return attr->c->event_spec[attr->address & 0xffff].dir;
251}
252
253static enum iio_event_type iio_ev_attr_type(struct iio_dev_attr *attr)
254{
255 return attr->c->event_spec[attr->address & 0xffff].type;
256}
257
258static enum iio_event_info iio_ev_attr_info(struct iio_dev_attr *attr)
259{
260 return (attr->address >> 16) & 0xffff;
261}
262
263static ssize_t iio_ev_state_store(struct device *dev,
264 struct device_attribute *attr,
265 const char *buf,
266 size_t len)
267{
268 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
269 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
270 int ret;
271 bool val;
272
273 ret = strtobool(buf, &val);
274 if (ret < 0)
275 return ret;
276
277 ret = indio_dev->info->write_event_config(indio_dev,
278 this_attr->c, iio_ev_attr_type(this_attr),
279 iio_ev_attr_dir(this_attr), val);
280
281 return (ret < 0) ? ret : len;
282}
283
284static ssize_t iio_ev_state_show(struct device *dev,
285 struct device_attribute *attr,
286 char *buf)
287{
288 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
289 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
290 int val;
291
292 val = indio_dev->info->read_event_config(indio_dev,
293 this_attr->c, iio_ev_attr_type(this_attr),
294 iio_ev_attr_dir(this_attr));
295 if (val < 0)
296 return val;
297 else
298 return sprintf(buf, "%d\n", val);
299}
300
301static ssize_t iio_ev_value_show(struct device *dev,
302 struct device_attribute *attr,
303 char *buf)
304{
305 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
306 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
307 int val, val2, val_arr[2];
308 int ret;
309
310 ret = indio_dev->info->read_event_value(indio_dev,
311 this_attr->c, iio_ev_attr_type(this_attr),
312 iio_ev_attr_dir(this_attr), iio_ev_attr_info(this_attr),
313 &val, &val2);
314 if (ret < 0)
315 return ret;
316 val_arr[0] = val;
317 val_arr[1] = val2;
318 return iio_format_value(buf, ret, 2, val_arr);
319}
320
321static ssize_t iio_ev_value_store(struct device *dev,
322 struct device_attribute *attr,
323 const char *buf,
324 size_t len)
325{
326 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
327 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
328 int val, val2;
329 int ret;
330
331 if (!indio_dev->info->write_event_value)
332 return -EINVAL;
333
334 ret = iio_str_to_fixpoint(buf, 100000, &val, &val2);
335 if (ret)
336 return ret;
337 ret = indio_dev->info->write_event_value(indio_dev,
338 this_attr->c, iio_ev_attr_type(this_attr),
339 iio_ev_attr_dir(this_attr), iio_ev_attr_info(this_attr),
340 val, val2);
341 if (ret < 0)
342 return ret;
343
344 return len;
345}
346
347static int iio_device_add_event(struct iio_dev *indio_dev,
348 const struct iio_chan_spec *chan, unsigned int spec_index,
349 enum iio_event_type type, enum iio_event_direction dir,
350 enum iio_shared_by shared_by, const unsigned long *mask)
351{
352 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
353 ssize_t (*show)(struct device *, struct device_attribute *, char *);
354 ssize_t (*store)(struct device *, struct device_attribute *,
355 const char *, size_t);
356 unsigned int attrcount = 0;
357 unsigned int i;
358 char *postfix;
359 int ret;
360
361 for_each_set_bit(i, mask, sizeof(*mask)*8) {
362 if (i >= ARRAY_SIZE(iio_ev_info_text))
363 return -EINVAL;
364 if (dir != IIO_EV_DIR_NONE)
365 postfix = kasprintf(GFP_KERNEL, "%s_%s_%s",
366 iio_ev_type_text[type],
367 iio_ev_dir_text[dir],
368 iio_ev_info_text[i]);
369 else
370 postfix = kasprintf(GFP_KERNEL, "%s_%s",
371 iio_ev_type_text[type],
372 iio_ev_info_text[i]);
373 if (postfix == NULL)
374 return -ENOMEM;
375
376 if (i == IIO_EV_INFO_ENABLE) {
377 show = iio_ev_state_show;
378 store = iio_ev_state_store;
379 } else {
380 show = iio_ev_value_show;
381 store = iio_ev_value_store;
382 }
383
384 ret = __iio_add_chan_devattr(postfix, chan, show, store,
385 (i << 16) | spec_index, shared_by, &indio_dev->dev,
386 &iio_dev_opaque->event_interface->dev_attr_list);
387 kfree(postfix);
388
389 if ((ret == -EBUSY) && (shared_by != IIO_SEPARATE))
390 continue;
391
392 if (ret)
393 return ret;
394
395 attrcount++;
396 }
397
398 return attrcount;
399}
400
401static int iio_device_add_event_sysfs(struct iio_dev *indio_dev,
402 struct iio_chan_spec const *chan)
403{
404 int ret = 0, i, attrcount = 0;
405 enum iio_event_direction dir;
406 enum iio_event_type type;
407
408 for (i = 0; i < chan->num_event_specs; i++) {
409 type = chan->event_spec[i].type;
410 dir = chan->event_spec[i].dir;
411
412 ret = iio_device_add_event(indio_dev, chan, i, type, dir,
413 IIO_SEPARATE, &chan->event_spec[i].mask_separate);
414 if (ret < 0)
415 return ret;
416 attrcount += ret;
417
418 ret = iio_device_add_event(indio_dev, chan, i, type, dir,
419 IIO_SHARED_BY_TYPE,
420 &chan->event_spec[i].mask_shared_by_type);
421 if (ret < 0)
422 return ret;
423 attrcount += ret;
424
425 ret = iio_device_add_event(indio_dev, chan, i, type, dir,
426 IIO_SHARED_BY_DIR,
427 &chan->event_spec[i].mask_shared_by_dir);
428 if (ret < 0)
429 return ret;
430 attrcount += ret;
431
432 ret = iio_device_add_event(indio_dev, chan, i, type, dir,
433 IIO_SHARED_BY_ALL,
434 &chan->event_spec[i].mask_shared_by_all);
435 if (ret < 0)
436 return ret;
437 attrcount += ret;
438 }
439 ret = attrcount;
440 return ret;
441}
442
443static inline int __iio_add_event_config_attrs(struct iio_dev *indio_dev)
444{
445 int j, ret, attrcount = 0;
446
447 /* Dynamically created from the channels array */
448 for (j = 0; j < indio_dev->num_channels; j++) {
449 ret = iio_device_add_event_sysfs(indio_dev,
450 &indio_dev->channels[j]);
451 if (ret < 0)
452 return ret;
453 attrcount += ret;
454 }
455 return attrcount;
456}
457
458static bool iio_check_for_dynamic_events(struct iio_dev *indio_dev)
459{
460 int j;
461
462 for (j = 0; j < indio_dev->num_channels; j++) {
463 if (indio_dev->channels[j].num_event_specs != 0)
464 return true;
465 }
466 return false;
467}
468
469static void iio_setup_ev_int(struct iio_event_interface *ev_int)
470{
471 INIT_KFIFO(ev_int->det_events);
472 init_waitqueue_head(&ev_int->wait);
473 mutex_init(&ev_int->read_lock);
474}
475
476static const char *iio_event_group_name = "events";
477int iio_device_register_eventset(struct iio_dev *indio_dev)
478{
479 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
480 struct iio_dev_attr *p;
481 int ret = 0, attrcount_orig = 0, attrcount, attrn;
482 struct attribute **attr;
483
484 if (!(indio_dev->info->event_attrs ||
485 iio_check_for_dynamic_events(indio_dev)))
486 return 0;
487
488 iio_dev_opaque->event_interface =
489 kzalloc(sizeof(struct iio_event_interface), GFP_KERNEL);
490 if (iio_dev_opaque->event_interface == NULL)
491 return -ENOMEM;
492
493 INIT_LIST_HEAD(&iio_dev_opaque->event_interface->dev_attr_list);
494
495 iio_setup_ev_int(iio_dev_opaque->event_interface);
496 if (indio_dev->info->event_attrs != NULL) {
497 attr = indio_dev->info->event_attrs->attrs;
498 while (*attr++ != NULL)
499 attrcount_orig++;
500 }
501 attrcount = attrcount_orig;
502 if (indio_dev->channels) {
503 ret = __iio_add_event_config_attrs(indio_dev);
504 if (ret < 0)
505 goto error_free_setup_event_lines;
506 attrcount += ret;
507 }
508
509 iio_dev_opaque->event_interface->group.name = iio_event_group_name;
510 iio_dev_opaque->event_interface->group.attrs = kcalloc(attrcount + 1,
511 sizeof(iio_dev_opaque->event_interface->group.attrs[0]),
512 GFP_KERNEL);
513 if (iio_dev_opaque->event_interface->group.attrs == NULL) {
514 ret = -ENOMEM;
515 goto error_free_setup_event_lines;
516 }
517 if (indio_dev->info->event_attrs)
518 memcpy(iio_dev_opaque->event_interface->group.attrs,
519 indio_dev->info->event_attrs->attrs,
520 sizeof(iio_dev_opaque->event_interface->group.attrs[0])
521 *attrcount_orig);
522 attrn = attrcount_orig;
523 /* Add all elements from the list. */
524 list_for_each_entry(p,
525 &iio_dev_opaque->event_interface->dev_attr_list,
526 l)
527 iio_dev_opaque->event_interface->group.attrs[attrn++] =
528 &p->dev_attr.attr;
529 indio_dev->groups[indio_dev->groupcounter++] =
530 &iio_dev_opaque->event_interface->group;
531
532 return 0;
533
534error_free_setup_event_lines:
535 iio_free_chan_devattr_list(&iio_dev_opaque->event_interface->dev_attr_list);
536 kfree(iio_dev_opaque->event_interface);
537 iio_dev_opaque->event_interface = NULL;
538 return ret;
539}
540
541/**
542 * iio_device_wakeup_eventset - Wakes up the event waitqueue
543 * @indio_dev: The IIO device
544 *
545 * Wakes up the event waitqueue used for poll() and blocking read().
546 * Should usually be called when the device is unregistered.
547 */
548void iio_device_wakeup_eventset(struct iio_dev *indio_dev)
549{
550 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
551
552 if (iio_dev_opaque->event_interface == NULL)
553 return;
554 wake_up(&iio_dev_opaque->event_interface->wait);
555}
556
557void iio_device_unregister_eventset(struct iio_dev *indio_dev)
558{
559 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
560
561 if (iio_dev_opaque->event_interface == NULL)
562 return;
563 iio_free_chan_devattr_list(&iio_dev_opaque->event_interface->dev_attr_list);
564 kfree(iio_dev_opaque->event_interface->group.attrs);
565 kfree(iio_dev_opaque->event_interface);
566}