1 /* Industrial I/O event handling
3 * Copyright (c) 2008 Jonathan Cameron
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.
9 * Based on elements of hwmon and input subsystems.
12 #include <linux/anon_inodes.h>
13 #include <linux/device.h>
15 #include <linux/kernel.h>
16 #include <linux/kfifo.h>
17 #include <linux/module.h>
18 #include <linux/poll.h>
19 #include <linux/sched.h>
20 #include <linux/slab.h>
21 #include <linux/uaccess.h>
22 #include <linux/wait.h>
23 #include <linux/iio/iio.h>
25 #include <linux/iio/sysfs.h>
26 #include <linux/iio/events.h>
29 * struct iio_event_interface - chrdev interface for an event line
30 * @wait: wait queue to allow blocking reads of events
31 * @det_events: list of detected events
32 * @dev_attr_list: list of event interface sysfs attribute
33 * @flags: file operations related flags including busy flag.
34 * @group: event interface sysfs attribute group
35 * @read_lock: lock to protect kfifo read operations
37 struct iio_event_interface {
38 wait_queue_head_t wait;
39 DECLARE_KFIFO(det_events, struct iio_event_data, 16);
41 struct list_head dev_attr_list;
43 struct attribute_group group;
44 struct mutex read_lock;
47 bool iio_event_enabled(const struct iio_event_interface *ev_int)
49 return !!test_bit(IIO_BUSY_BIT_POS, &ev_int->flags);
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
58 * Note: The caller must make sure that this function is not running
59 * concurrently for the same indio_dev more than once.
61 int iio_push_event(struct iio_dev *indio_dev, u64 ev_code, s64 timestamp)
63 struct iio_event_interface *ev_int = indio_dev->event_interface;
64 struct iio_event_data ev;
67 /* Does anyone care? */
68 if (iio_event_enabled(ev_int)) {
71 ev.timestamp = timestamp;
73 copied = kfifo_put(&ev_int->det_events, ev);
75 wake_up_poll(&ev_int->wait, POLLIN);
80 EXPORT_SYMBOL(iio_push_event);
83 * iio_event_poll() - poll the event queue to find out if it has data
84 * @filep: File structure pointer to identify the device
85 * @wait: Poll table pointer to add the wait queue on
87 * Return: (POLLIN | POLLRDNORM) if data is available for reading
88 * or a negative error code on failure
90 static unsigned int iio_event_poll(struct file *filep,
91 struct poll_table_struct *wait)
93 struct iio_dev *indio_dev = filep->private_data;
94 struct iio_event_interface *ev_int = indio_dev->event_interface;
95 unsigned int events = 0;
100 poll_wait(filep, &ev_int->wait, wait);
102 if (!kfifo_is_empty(&ev_int->det_events))
103 events = POLLIN | POLLRDNORM;
108 static ssize_t iio_event_chrdev_read(struct file *filep,
113 struct iio_dev *indio_dev = filep->private_data;
114 struct iio_event_interface *ev_int = indio_dev->event_interface;
118 if (!indio_dev->info)
121 if (count < sizeof(struct iio_event_data))
125 if (kfifo_is_empty(&ev_int->det_events)) {
126 if (filep->f_flags & O_NONBLOCK)
129 ret = wait_event_interruptible(ev_int->wait,
130 !kfifo_is_empty(&ev_int->det_events) ||
131 indio_dev->info == NULL);
134 if (indio_dev->info == NULL)
138 if (mutex_lock_interruptible(&ev_int->read_lock))
140 ret = kfifo_to_user(&ev_int->det_events, buf, count, &copied);
141 mutex_unlock(&ev_int->read_lock);
147 * If we couldn't read anything from the fifo (a different
148 * thread might have been faster) we either return -EAGAIN if
149 * the file descriptor is non-blocking, otherwise we go back to
150 * sleep and wait for more data to arrive.
152 if (copied == 0 && (filep->f_flags & O_NONBLOCK))
155 } while (copied == 0);
160 static int iio_event_chrdev_release(struct inode *inode, struct file *filep)
162 struct iio_dev *indio_dev = filep->private_data;
163 struct iio_event_interface *ev_int = indio_dev->event_interface;
165 clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags);
167 iio_device_put(indio_dev);
172 static const struct file_operations iio_event_chrdev_fileops = {
173 .read = iio_event_chrdev_read,
174 .poll = iio_event_poll,
175 .release = iio_event_chrdev_release,
176 .owner = THIS_MODULE,
177 .llseek = noop_llseek,
180 int iio_event_getfd(struct iio_dev *indio_dev)
182 struct iio_event_interface *ev_int = indio_dev->event_interface;
188 fd = mutex_lock_interruptible(&indio_dev->mlock);
192 if (test_and_set_bit(IIO_BUSY_BIT_POS, &ev_int->flags)) {
197 iio_device_get(indio_dev);
199 fd = anon_inode_getfd("iio:event", &iio_event_chrdev_fileops,
200 indio_dev, O_RDONLY | O_CLOEXEC);
202 clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags);
203 iio_device_put(indio_dev);
205 kfifo_reset_out(&ev_int->det_events);
209 mutex_unlock(&indio_dev->mlock);
213 static const char * const iio_ev_type_text[] = {
214 [IIO_EV_TYPE_THRESH] = "thresh",
215 [IIO_EV_TYPE_MAG] = "mag",
216 [IIO_EV_TYPE_ROC] = "roc",
217 [IIO_EV_TYPE_THRESH_ADAPTIVE] = "thresh_adaptive",
218 [IIO_EV_TYPE_MAG_ADAPTIVE] = "mag_adaptive",
219 [IIO_EV_TYPE_CHANGE] = "change",
222 static const char * const iio_ev_dir_text[] = {
223 [IIO_EV_DIR_EITHER] = "either",
224 [IIO_EV_DIR_RISING] = "rising",
225 [IIO_EV_DIR_FALLING] = "falling"
228 static const char * const iio_ev_info_text[] = {
229 [IIO_EV_INFO_ENABLE] = "en",
230 [IIO_EV_INFO_VALUE] = "value",
231 [IIO_EV_INFO_HYSTERESIS] = "hysteresis",
232 [IIO_EV_INFO_PERIOD] = "period",
233 [IIO_EV_INFO_HIGH_PASS_FILTER_3DB] = "high_pass_filter_3db",
234 [IIO_EV_INFO_LOW_PASS_FILTER_3DB] = "low_pass_filter_3db",
237 static enum iio_event_direction iio_ev_attr_dir(struct iio_dev_attr *attr)
239 return attr->c->event_spec[attr->address & 0xffff].dir;
242 static enum iio_event_type iio_ev_attr_type(struct iio_dev_attr *attr)
244 return attr->c->event_spec[attr->address & 0xffff].type;
247 static enum iio_event_info iio_ev_attr_info(struct iio_dev_attr *attr)
249 return (attr->address >> 16) & 0xffff;
252 static ssize_t iio_ev_state_store(struct device *dev,
253 struct device_attribute *attr,
257 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
258 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
262 ret = strtobool(buf, &val);
266 ret = indio_dev->info->write_event_config(indio_dev,
267 this_attr->c, iio_ev_attr_type(this_attr),
268 iio_ev_attr_dir(this_attr), val);
270 return (ret < 0) ? ret : len;
273 static ssize_t iio_ev_state_show(struct device *dev,
274 struct device_attribute *attr,
277 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
278 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
281 val = indio_dev->info->read_event_config(indio_dev,
282 this_attr->c, iio_ev_attr_type(this_attr),
283 iio_ev_attr_dir(this_attr));
287 return sprintf(buf, "%d\n", val);
290 static ssize_t iio_ev_value_show(struct device *dev,
291 struct device_attribute *attr,
294 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
295 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
296 int val, val2, val_arr[2];
299 ret = indio_dev->info->read_event_value(indio_dev,
300 this_attr->c, iio_ev_attr_type(this_attr),
301 iio_ev_attr_dir(this_attr), iio_ev_attr_info(this_attr),
307 return iio_format_value(buf, ret, 2, val_arr);
310 static ssize_t iio_ev_value_store(struct device *dev,
311 struct device_attribute *attr,
315 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
316 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
320 if (!indio_dev->info->write_event_value)
323 ret = iio_str_to_fixpoint(buf, 100000, &val, &val2);
326 ret = indio_dev->info->write_event_value(indio_dev,
327 this_attr->c, iio_ev_attr_type(this_attr),
328 iio_ev_attr_dir(this_attr), iio_ev_attr_info(this_attr),
336 static int iio_device_add_event(struct iio_dev *indio_dev,
337 const struct iio_chan_spec *chan, unsigned int spec_index,
338 enum iio_event_type type, enum iio_event_direction dir,
339 enum iio_shared_by shared_by, const unsigned long *mask)
341 ssize_t (*show)(struct device *, struct device_attribute *, char *);
342 ssize_t (*store)(struct device *, struct device_attribute *,
343 const char *, size_t);
344 unsigned int attrcount = 0;
349 for_each_set_bit(i, mask, sizeof(*mask)*8) {
350 if (i >= ARRAY_SIZE(iio_ev_info_text))
352 if (dir != IIO_EV_DIR_NONE)
353 postfix = kasprintf(GFP_KERNEL, "%s_%s_%s",
354 iio_ev_type_text[type],
355 iio_ev_dir_text[dir],
356 iio_ev_info_text[i]);
358 postfix = kasprintf(GFP_KERNEL, "%s_%s",
359 iio_ev_type_text[type],
360 iio_ev_info_text[i]);
364 if (i == IIO_EV_INFO_ENABLE) {
365 show = iio_ev_state_show;
366 store = iio_ev_state_store;
368 show = iio_ev_value_show;
369 store = iio_ev_value_store;
372 ret = __iio_add_chan_devattr(postfix, chan, show, store,
373 (i << 16) | spec_index, shared_by, &indio_dev->dev,
374 &indio_dev->event_interface->dev_attr_list);
377 if ((ret == -EBUSY) && (shared_by != IIO_SEPARATE))
389 static int iio_device_add_event_sysfs(struct iio_dev *indio_dev,
390 struct iio_chan_spec const *chan)
392 int ret = 0, i, attrcount = 0;
393 enum iio_event_direction dir;
394 enum iio_event_type type;
396 for (i = 0; i < chan->num_event_specs; i++) {
397 type = chan->event_spec[i].type;
398 dir = chan->event_spec[i].dir;
400 ret = iio_device_add_event(indio_dev, chan, i, type, dir,
401 IIO_SEPARATE, &chan->event_spec[i].mask_separate);
406 ret = iio_device_add_event(indio_dev, chan, i, type, dir,
408 &chan->event_spec[i].mask_shared_by_type);
413 ret = iio_device_add_event(indio_dev, chan, i, type, dir,
415 &chan->event_spec[i].mask_shared_by_dir);
420 ret = iio_device_add_event(indio_dev, chan, i, type, dir,
422 &chan->event_spec[i].mask_shared_by_all);
431 static inline int __iio_add_event_config_attrs(struct iio_dev *indio_dev)
433 int j, ret, attrcount = 0;
435 /* Dynamically created from the channels array */
436 for (j = 0; j < indio_dev->num_channels; j++) {
437 ret = iio_device_add_event_sysfs(indio_dev,
438 &indio_dev->channels[j]);
446 static bool iio_check_for_dynamic_events(struct iio_dev *indio_dev)
450 for (j = 0; j < indio_dev->num_channels; j++) {
451 if (indio_dev->channels[j].num_event_specs != 0)
457 static void iio_setup_ev_int(struct iio_event_interface *ev_int)
459 INIT_KFIFO(ev_int->det_events);
460 init_waitqueue_head(&ev_int->wait);
461 mutex_init(&ev_int->read_lock);
464 static const char *iio_event_group_name = "events";
465 int iio_device_register_eventset(struct iio_dev *indio_dev)
467 struct iio_dev_attr *p;
468 int ret = 0, attrcount_orig = 0, attrcount, attrn;
469 struct attribute **attr;
471 if (!(indio_dev->info->event_attrs ||
472 iio_check_for_dynamic_events(indio_dev)))
475 indio_dev->event_interface =
476 kzalloc(sizeof(struct iio_event_interface), GFP_KERNEL);
477 if (indio_dev->event_interface == NULL)
480 INIT_LIST_HEAD(&indio_dev->event_interface->dev_attr_list);
482 iio_setup_ev_int(indio_dev->event_interface);
483 if (indio_dev->info->event_attrs != NULL) {
484 attr = indio_dev->info->event_attrs->attrs;
485 while (*attr++ != NULL)
488 attrcount = attrcount_orig;
489 if (indio_dev->channels) {
490 ret = __iio_add_event_config_attrs(indio_dev);
492 goto error_free_setup_event_lines;
496 indio_dev->event_interface->group.name = iio_event_group_name;
497 indio_dev->event_interface->group.attrs = kcalloc(attrcount + 1,
498 sizeof(indio_dev->event_interface->group.attrs[0]),
500 if (indio_dev->event_interface->group.attrs == NULL) {
502 goto error_free_setup_event_lines;
504 if (indio_dev->info->event_attrs)
505 memcpy(indio_dev->event_interface->group.attrs,
506 indio_dev->info->event_attrs->attrs,
507 sizeof(indio_dev->event_interface->group.attrs[0])
509 attrn = attrcount_orig;
510 /* Add all elements from the list. */
511 list_for_each_entry(p,
512 &indio_dev->event_interface->dev_attr_list,
514 indio_dev->event_interface->group.attrs[attrn++] =
516 indio_dev->groups[indio_dev->groupcounter++] =
517 &indio_dev->event_interface->group;
521 error_free_setup_event_lines:
522 iio_free_chan_devattr_list(&indio_dev->event_interface->dev_attr_list);
523 kfree(indio_dev->event_interface);
524 indio_dev->event_interface = NULL;
529 * iio_device_wakeup_eventset - Wakes up the event waitqueue
530 * @indio_dev: The IIO device
532 * Wakes up the event waitqueue used for poll() and blocking read().
533 * Should usually be called when the device is unregistered.
535 void iio_device_wakeup_eventset(struct iio_dev *indio_dev)
537 if (indio_dev->event_interface == NULL)
539 wake_up(&indio_dev->event_interface->wait);
542 void iio_device_unregister_eventset(struct iio_dev *indio_dev)
544 if (indio_dev->event_interface == NULL)
546 iio_free_chan_devattr_list(&indio_dev->event_interface->dev_attr_list);
547 kfree(indio_dev->event_interface->group.attrs);
548 kfree(indio_dev->event_interface);