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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 * @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(filep, &ev_int->wait, 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(&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, &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, &ev_int->flags)) {
206 fd = -EBUSY;
207 goto unlock;
208 }
209
210 iio_device_get(indio_dev);
211
212 fd = anon_inode_getfd("iio:event", &iio_event_chrdev_fileops,
213 indio_dev, O_RDONLY | O_CLOEXEC);
214 if (fd < 0) {
215 clear_bit(IIO_BUSY_BIT_POS, &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(&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};
256
257static enum iio_event_direction iio_ev_attr_dir(struct iio_dev_attr *attr)
258{
259 return attr->c->event_spec[attr->address & 0xffff].dir;
260}
261
262static enum iio_event_type iio_ev_attr_type(struct iio_dev_attr *attr)
263{
264 return attr->c->event_spec[attr->address & 0xffff].type;
265}
266
267static enum iio_event_info iio_ev_attr_info(struct iio_dev_attr *attr)
268{
269 return (attr->address >> 16) & 0xffff;
270}
271
272static ssize_t iio_ev_state_store(struct device *dev,
273 struct device_attribute *attr,
274 const char *buf,
275 size_t len)
276{
277 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
278 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
279 int ret;
280 bool val;
281
282 ret = kstrtobool(buf, &val);
283 if (ret < 0)
284 return ret;
285
286 ret = indio_dev->info->write_event_config(indio_dev,
287 this_attr->c, iio_ev_attr_type(this_attr),
288 iio_ev_attr_dir(this_attr), val);
289
290 return (ret < 0) ? ret : len;
291}
292
293static ssize_t iio_ev_state_show(struct device *dev,
294 struct device_attribute *attr,
295 char *buf)
296{
297 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
298 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
299 int val;
300
301 val = indio_dev->info->read_event_config(indio_dev,
302 this_attr->c, iio_ev_attr_type(this_attr),
303 iio_ev_attr_dir(this_attr));
304 if (val < 0)
305 return val;
306 else
307 return sysfs_emit(buf, "%d\n", val);
308}
309
310static ssize_t iio_ev_value_show(struct device *dev,
311 struct device_attribute *attr,
312 char *buf)
313{
314 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
315 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
316 int val, val2, val_arr[2];
317 int ret;
318
319 ret = indio_dev->info->read_event_value(indio_dev,
320 this_attr->c, iio_ev_attr_type(this_attr),
321 iio_ev_attr_dir(this_attr), iio_ev_attr_info(this_attr),
322 &val, &val2);
323 if (ret < 0)
324 return ret;
325 val_arr[0] = val;
326 val_arr[1] = val2;
327 return iio_format_value(buf, ret, 2, val_arr);
328}
329
330static ssize_t iio_ev_value_store(struct device *dev,
331 struct device_attribute *attr,
332 const char *buf,
333 size_t len)
334{
335 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
336 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
337 int val, val2;
338 int ret;
339
340 if (!indio_dev->info->write_event_value)
341 return -EINVAL;
342
343 ret = iio_str_to_fixpoint(buf, 100000, &val, &val2);
344 if (ret)
345 return ret;
346 ret = indio_dev->info->write_event_value(indio_dev,
347 this_attr->c, iio_ev_attr_type(this_attr),
348 iio_ev_attr_dir(this_attr), iio_ev_attr_info(this_attr),
349 val, val2);
350 if (ret < 0)
351 return ret;
352
353 return len;
354}
355
356static int iio_device_add_event(struct iio_dev *indio_dev,
357 const struct iio_chan_spec *chan, unsigned int spec_index,
358 enum iio_event_type type, enum iio_event_direction dir,
359 enum iio_shared_by shared_by, const unsigned long *mask)
360{
361 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
362 ssize_t (*show)(struct device *dev, struct device_attribute *attr,
363 char *buf);
364 ssize_t (*store)(struct device *dev, struct device_attribute *attr,
365 const char *buf, size_t len);
366 unsigned int attrcount = 0;
367 unsigned int i;
368 char *postfix;
369 int ret;
370
371 for_each_set_bit(i, mask, sizeof(*mask)*8) {
372 if (i >= ARRAY_SIZE(iio_ev_info_text))
373 return -EINVAL;
374 if (dir != IIO_EV_DIR_NONE)
375 postfix = kasprintf(GFP_KERNEL, "%s_%s_%s",
376 iio_ev_type_text[type],
377 iio_ev_dir_text[dir],
378 iio_ev_info_text[i]);
379 else
380 postfix = kasprintf(GFP_KERNEL, "%s_%s",
381 iio_ev_type_text[type],
382 iio_ev_info_text[i]);
383 if (postfix == NULL)
384 return -ENOMEM;
385
386 if (i == IIO_EV_INFO_ENABLE) {
387 show = iio_ev_state_show;
388 store = iio_ev_state_store;
389 } else {
390 show = iio_ev_value_show;
391 store = iio_ev_value_store;
392 }
393
394 ret = __iio_add_chan_devattr(postfix, chan, show, store,
395 (i << 16) | spec_index, shared_by, &indio_dev->dev,
396 NULL,
397 &iio_dev_opaque->event_interface->dev_attr_list);
398 kfree(postfix);
399
400 if ((ret == -EBUSY) && (shared_by != IIO_SEPARATE))
401 continue;
402
403 if (ret)
404 return ret;
405
406 attrcount++;
407 }
408
409 return attrcount;
410}
411
412static int iio_device_add_event_sysfs(struct iio_dev *indio_dev,
413 struct iio_chan_spec const *chan)
414{
415 int ret = 0, i, attrcount = 0;
416 enum iio_event_direction dir;
417 enum iio_event_type type;
418
419 for (i = 0; i < chan->num_event_specs; i++) {
420 type = chan->event_spec[i].type;
421 dir = chan->event_spec[i].dir;
422
423 ret = iio_device_add_event(indio_dev, chan, i, type, dir,
424 IIO_SEPARATE, &chan->event_spec[i].mask_separate);
425 if (ret < 0)
426 return ret;
427 attrcount += ret;
428
429 ret = iio_device_add_event(indio_dev, chan, i, type, dir,
430 IIO_SHARED_BY_TYPE,
431 &chan->event_spec[i].mask_shared_by_type);
432 if (ret < 0)
433 return ret;
434 attrcount += ret;
435
436 ret = iio_device_add_event(indio_dev, chan, i, type, dir,
437 IIO_SHARED_BY_DIR,
438 &chan->event_spec[i].mask_shared_by_dir);
439 if (ret < 0)
440 return ret;
441 attrcount += ret;
442
443 ret = iio_device_add_event(indio_dev, chan, i, type, dir,
444 IIO_SHARED_BY_ALL,
445 &chan->event_spec[i].mask_shared_by_all);
446 if (ret < 0)
447 return ret;
448 attrcount += ret;
449 }
450 ret = attrcount;
451 return ret;
452}
453
454static inline int __iio_add_event_config_attrs(struct iio_dev *indio_dev)
455{
456 int j, ret, attrcount = 0;
457
458 /* Dynamically created from the channels array */
459 for (j = 0; j < indio_dev->num_channels; j++) {
460 ret = iio_device_add_event_sysfs(indio_dev,
461 &indio_dev->channels[j]);
462 if (ret < 0)
463 return ret;
464 attrcount += ret;
465 }
466 return attrcount;
467}
468
469static bool iio_check_for_dynamic_events(struct iio_dev *indio_dev)
470{
471 int j;
472
473 for (j = 0; j < indio_dev->num_channels; j++) {
474 if (indio_dev->channels[j].num_event_specs != 0)
475 return true;
476 }
477 return false;
478}
479
480static void iio_setup_ev_int(struct iio_event_interface *ev_int)
481{
482 INIT_KFIFO(ev_int->det_events);
483 init_waitqueue_head(&ev_int->wait);
484 mutex_init(&ev_int->read_lock);
485}
486
487static long iio_event_ioctl(struct iio_dev *indio_dev, struct file *filp,
488 unsigned int cmd, unsigned long arg)
489{
490 int __user *ip = (int __user *)arg;
491 int fd;
492
493 if (cmd == IIO_GET_EVENT_FD_IOCTL) {
494 fd = iio_event_getfd(indio_dev);
495 if (fd < 0)
496 return fd;
497 if (copy_to_user(ip, &fd, sizeof(fd)))
498 return -EFAULT;
499 return 0;
500 }
501
502 return IIO_IOCTL_UNHANDLED;
503}
504
505static const char *iio_event_group_name = "events";
506int iio_device_register_eventset(struct iio_dev *indio_dev)
507{
508 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
509 struct iio_event_interface *ev_int;
510 struct iio_dev_attr *p;
511 int ret = 0, attrcount_orig = 0, attrcount, attrn;
512 struct attribute **attr;
513
514 if (!(indio_dev->info->event_attrs ||
515 iio_check_for_dynamic_events(indio_dev)))
516 return 0;
517
518 ev_int = kzalloc(sizeof(struct iio_event_interface), GFP_KERNEL);
519 if (ev_int == NULL)
520 return -ENOMEM;
521
522 iio_dev_opaque->event_interface = ev_int;
523
524 INIT_LIST_HEAD(&ev_int->dev_attr_list);
525
526 iio_setup_ev_int(ev_int);
527 if (indio_dev->info->event_attrs != NULL) {
528 attr = indio_dev->info->event_attrs->attrs;
529 while (*attr++ != NULL)
530 attrcount_orig++;
531 }
532 attrcount = attrcount_orig;
533 if (indio_dev->channels) {
534 ret = __iio_add_event_config_attrs(indio_dev);
535 if (ret < 0)
536 goto error_free_setup_event_lines;
537 attrcount += ret;
538 }
539
540 ev_int->group.name = iio_event_group_name;
541 ev_int->group.attrs = kcalloc(attrcount + 1,
542 sizeof(ev_int->group.attrs[0]),
543 GFP_KERNEL);
544 if (ev_int->group.attrs == NULL) {
545 ret = -ENOMEM;
546 goto error_free_setup_event_lines;
547 }
548 if (indio_dev->info->event_attrs)
549 memcpy(ev_int->group.attrs,
550 indio_dev->info->event_attrs->attrs,
551 sizeof(ev_int->group.attrs[0]) * attrcount_orig);
552 attrn = attrcount_orig;
553 /* Add all elements from the list. */
554 list_for_each_entry(p, &ev_int->dev_attr_list, l)
555 ev_int->group.attrs[attrn++] = &p->dev_attr.attr;
556
557 ret = iio_device_register_sysfs_group(indio_dev, &ev_int->group);
558 if (ret)
559 goto error_free_group_attrs;
560
561 ev_int->ioctl_handler.ioctl = iio_event_ioctl;
562 iio_device_ioctl_handler_register(&iio_dev_opaque->indio_dev,
563 &ev_int->ioctl_handler);
564
565 return 0;
566
567error_free_group_attrs:
568 kfree(ev_int->group.attrs);
569error_free_setup_event_lines:
570 iio_free_chan_devattr_list(&ev_int->dev_attr_list);
571 kfree(ev_int);
572 iio_dev_opaque->event_interface = NULL;
573 return ret;
574}
575
576/**
577 * iio_device_wakeup_eventset - Wakes up the event waitqueue
578 * @indio_dev: The IIO device
579 *
580 * Wakes up the event waitqueue used for poll() and blocking read().
581 * Should usually be called when the device is unregistered.
582 */
583void iio_device_wakeup_eventset(struct iio_dev *indio_dev)
584{
585 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
586
587 if (iio_dev_opaque->event_interface == NULL)
588 return;
589 wake_up(&iio_dev_opaque->event_interface->wait);
590}
591
592void iio_device_unregister_eventset(struct iio_dev *indio_dev)
593{
594 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
595 struct iio_event_interface *ev_int = iio_dev_opaque->event_interface;
596
597 if (ev_int == NULL)
598 return;
599
600 iio_device_ioctl_handler_unregister(&ev_int->ioctl_handler);
601 iio_free_chan_devattr_list(&ev_int->dev_attr_list);
602 kfree(ev_int->group.attrs);
603 kfree(ev_int);
604 iio_dev_opaque->event_interface = NULL;
605}