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
36 struct iio_event_interface {
37 wait_queue_head_t wait;
38 DECLARE_KFIFO(det_events, struct iio_event_data, 16);
40 struct list_head dev_attr_list;
42 struct attribute_group group;
46 * iio_push_event() - try to add event to the list for userspace reading
47 * @indio_dev: IIO device structure
48 * @ev_code: What event
49 * @timestamp: When the event occurred
51 int iio_push_event(struct iio_dev *indio_dev, u64 ev_code, s64 timestamp)
53 struct iio_event_interface *ev_int = indio_dev->event_interface;
54 struct iio_event_data ev;
58 /* Does anyone care? */
59 spin_lock_irqsave(&ev_int->wait.lock, flags);
60 if (test_bit(IIO_BUSY_BIT_POS, &ev_int->flags)) {
63 ev.timestamp = timestamp;
65 copied = kfifo_put(&ev_int->det_events, ev);
67 wake_up_locked_poll(&ev_int->wait, POLLIN);
69 spin_unlock_irqrestore(&ev_int->wait.lock, flags);
73 EXPORT_SYMBOL(iio_push_event);
76 * iio_event_poll() - poll the event queue to find out if it has data
78 static unsigned int iio_event_poll(struct file *filep,
79 struct poll_table_struct *wait)
81 struct iio_dev *indio_dev = filep->private_data;
82 struct iio_event_interface *ev_int = indio_dev->event_interface;
83 unsigned int events = 0;
88 poll_wait(filep, &ev_int->wait, wait);
90 spin_lock_irq(&ev_int->wait.lock);
91 if (!kfifo_is_empty(&ev_int->det_events))
92 events = POLLIN | POLLRDNORM;
93 spin_unlock_irq(&ev_int->wait.lock);
98 static ssize_t iio_event_chrdev_read(struct file *filep,
103 struct iio_dev *indio_dev = filep->private_data;
104 struct iio_event_interface *ev_int = indio_dev->event_interface;
108 if (!indio_dev->info)
111 if (count < sizeof(struct iio_event_data))
114 spin_lock_irq(&ev_int->wait.lock);
115 if (kfifo_is_empty(&ev_int->det_events)) {
116 if (filep->f_flags & O_NONBLOCK) {
120 /* Blocking on device; waiting for something to be there */
121 ret = wait_event_interruptible_locked_irq(ev_int->wait,
122 !kfifo_is_empty(&ev_int->det_events) ||
123 indio_dev->info == NULL);
126 if (indio_dev->info == NULL) {
130 /* Single access device so no one else can get the data */
133 ret = kfifo_to_user(&ev_int->det_events, buf, count, &copied);
136 spin_unlock_irq(&ev_int->wait.lock);
138 return ret ? ret : copied;
141 static int iio_event_chrdev_release(struct inode *inode, struct file *filep)
143 struct iio_dev *indio_dev = filep->private_data;
144 struct iio_event_interface *ev_int = indio_dev->event_interface;
146 spin_lock_irq(&ev_int->wait.lock);
147 __clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags);
149 * In order to maintain a clean state for reopening,
150 * clear out any awaiting events. The mask will prevent
151 * any new __iio_push_event calls running.
153 kfifo_reset_out(&ev_int->det_events);
154 spin_unlock_irq(&ev_int->wait.lock);
156 iio_device_put(indio_dev);
161 static const struct file_operations iio_event_chrdev_fileops = {
162 .read = iio_event_chrdev_read,
163 .poll = iio_event_poll,
164 .release = iio_event_chrdev_release,
165 .owner = THIS_MODULE,
166 .llseek = noop_llseek,
169 int iio_event_getfd(struct iio_dev *indio_dev)
171 struct iio_event_interface *ev_int = indio_dev->event_interface;
177 spin_lock_irq(&ev_int->wait.lock);
178 if (__test_and_set_bit(IIO_BUSY_BIT_POS, &ev_int->flags)) {
179 spin_unlock_irq(&ev_int->wait.lock);
182 spin_unlock_irq(&ev_int->wait.lock);
183 iio_device_get(indio_dev);
185 fd = anon_inode_getfd("iio:event", &iio_event_chrdev_fileops,
186 indio_dev, O_RDONLY | O_CLOEXEC);
188 spin_lock_irq(&ev_int->wait.lock);
189 __clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags);
190 spin_unlock_irq(&ev_int->wait.lock);
191 iio_device_put(indio_dev);
196 static const char * const iio_ev_type_text[] = {
197 [IIO_EV_TYPE_THRESH] = "thresh",
198 [IIO_EV_TYPE_MAG] = "mag",
199 [IIO_EV_TYPE_ROC] = "roc",
200 [IIO_EV_TYPE_THRESH_ADAPTIVE] = "thresh_adaptive",
201 [IIO_EV_TYPE_MAG_ADAPTIVE] = "mag_adaptive",
204 static const char * const iio_ev_dir_text[] = {
205 [IIO_EV_DIR_EITHER] = "either",
206 [IIO_EV_DIR_RISING] = "rising",
207 [IIO_EV_DIR_FALLING] = "falling"
210 static const char * const iio_ev_info_text[] = {
211 [IIO_EV_INFO_ENABLE] = "en",
212 [IIO_EV_INFO_VALUE] = "value",
213 [IIO_EV_INFO_HYSTERESIS] = "hysteresis",
216 static enum iio_event_direction iio_ev_attr_dir(struct iio_dev_attr *attr)
218 return attr->c->event_spec[attr->address & 0xffff].dir;
221 static enum iio_event_type iio_ev_attr_type(struct iio_dev_attr *attr)
223 return attr->c->event_spec[attr->address & 0xffff].type;
226 static enum iio_event_info iio_ev_attr_info(struct iio_dev_attr *attr)
228 return (attr->address >> 16) & 0xffff;
231 static ssize_t iio_ev_state_store(struct device *dev,
232 struct device_attribute *attr,
236 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
237 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
241 ret = strtobool(buf, &val);
245 if (indio_dev->info->write_event_config)
246 ret = indio_dev->info->write_event_config(indio_dev,
247 this_attr->address, val);
249 ret = indio_dev->info->write_event_config_new(indio_dev,
250 this_attr->c, iio_ev_attr_type(this_attr),
251 iio_ev_attr_dir(this_attr), val);
253 return (ret < 0) ? ret : len;
256 static ssize_t iio_ev_state_show(struct device *dev,
257 struct device_attribute *attr,
260 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
261 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
264 if (indio_dev->info->read_event_config)
265 val = indio_dev->info->read_event_config(indio_dev,
268 val = indio_dev->info->read_event_config_new(indio_dev,
269 this_attr->c, iio_ev_attr_type(this_attr),
270 iio_ev_attr_dir(this_attr));
274 return sprintf(buf, "%d\n", val);
277 static ssize_t iio_ev_value_show(struct device *dev,
278 struct device_attribute *attr,
281 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
282 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
286 if (indio_dev->info->read_event_value) {
287 ret = indio_dev->info->read_event_value(indio_dev,
288 this_attr->address, &val);
291 return sprintf(buf, "%d\n", val);
293 ret = indio_dev->info->read_event_value_new(indio_dev,
294 this_attr->c, iio_ev_attr_type(this_attr),
295 iio_ev_attr_dir(this_attr), iio_ev_attr_info(this_attr),
299 return iio_format_value(buf, ret, val, val2);
303 static ssize_t iio_ev_value_store(struct device *dev,
304 struct device_attribute *attr,
308 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
309 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
313 if (!indio_dev->info->write_event_value &&
314 !indio_dev->info->write_event_value_new)
317 if (indio_dev->info->write_event_value) {
318 ret = kstrtoint(buf, 10, &val);
321 ret = indio_dev->info->write_event_value(indio_dev,
322 this_attr->address, val);
324 ret = iio_str_to_fixpoint(buf, 100000, &val, &val2);
327 ret = indio_dev->info->write_event_value_new(indio_dev,
328 this_attr->c, iio_ev_attr_type(this_attr),
329 iio_ev_attr_dir(this_attr), iio_ev_attr_info(this_attr),
338 static int iio_device_add_event(struct iio_dev *indio_dev,
339 const struct iio_chan_spec *chan, unsigned int spec_index,
340 enum iio_event_type type, enum iio_event_direction dir,
341 enum iio_shared_by shared_by, const unsigned long *mask)
343 ssize_t (*show)(struct device *, struct device_attribute *, char *);
344 ssize_t (*store)(struct device *, struct device_attribute *,
345 const char *, size_t);
346 unsigned int attrcount = 0;
351 for_each_set_bit(i, mask, sizeof(*mask)) {
352 postfix = kasprintf(GFP_KERNEL, "%s_%s_%s",
353 iio_ev_type_text[type], iio_ev_dir_text[dir],
354 iio_ev_info_text[i]);
358 if (i == IIO_EV_INFO_ENABLE) {
359 show = iio_ev_state_show;
360 store = iio_ev_state_store;
362 show = iio_ev_value_show;
363 store = iio_ev_value_store;
366 ret = __iio_add_chan_devattr(postfix, chan, show, store,
367 (i << 16) | spec_index, shared_by, &indio_dev->dev,
368 &indio_dev->event_interface->dev_attr_list);
380 static int iio_device_add_event_sysfs_new(struct iio_dev *indio_dev,
381 struct iio_chan_spec const *chan)
383 int ret = 0, i, attrcount = 0;
384 enum iio_event_direction dir;
385 enum iio_event_type type;
387 for (i = 0; i < chan->num_event_specs; i++) {
388 type = chan->event_spec[i].type;
389 dir = chan->event_spec[i].dir;
391 ret = iio_device_add_event(indio_dev, chan, i, type, dir,
392 IIO_SEPARATE, &chan->event_spec[i].mask_separate);
397 ret = iio_device_add_event(indio_dev, chan, i, type, dir,
399 &chan->event_spec[i].mask_shared_by_type);
404 ret = iio_device_add_event(indio_dev, chan, i, type, dir,
406 &chan->event_spec[i].mask_shared_by_dir);
411 ret = iio_device_add_event(indio_dev, chan, i, type, dir,
413 &chan->event_spec[i].mask_shared_by_all);
423 static int iio_device_add_event_sysfs_old(struct iio_dev *indio_dev,
424 struct iio_chan_spec const *chan)
426 int ret = 0, i, attrcount = 0;
429 if (!chan->event_mask)
432 for_each_set_bit(i, &chan->event_mask, sizeof(chan->event_mask)*8) {
433 postfix = kasprintf(GFP_KERNEL, "%s_%s_en",
434 iio_ev_type_text[i/IIO_EV_DIR_MAX],
435 iio_ev_dir_text[i%IIO_EV_DIR_MAX]);
436 if (postfix == NULL) {
441 mask = IIO_MOD_EVENT_CODE(chan->type, 0, chan->channel2,
444 else if (chan->differential)
445 mask = IIO_EVENT_CODE(chan->type,
453 mask = IIO_UNMOD_EVENT_CODE(chan->type,
458 ret = __iio_add_chan_devattr(postfix,
465 &indio_dev->event_interface->
471 postfix = kasprintf(GFP_KERNEL, "%s_%s_value",
472 iio_ev_type_text[i/IIO_EV_DIR_MAX],
473 iio_ev_dir_text[i%IIO_EV_DIR_MAX]);
474 if (postfix == NULL) {
478 ret = __iio_add_chan_devattr(postfix, chan,
484 &indio_dev->event_interface->
497 static int iio_device_add_event_sysfs(struct iio_dev *indio_dev,
498 struct iio_chan_spec const *chan)
500 if (chan->event_mask)
501 return iio_device_add_event_sysfs_old(indio_dev, chan);
503 return iio_device_add_event_sysfs_new(indio_dev, chan);
506 static inline int __iio_add_event_config_attrs(struct iio_dev *indio_dev)
508 int j, ret, attrcount = 0;
510 /* Dynically created from the channels array */
511 for (j = 0; j < indio_dev->num_channels; j++) {
512 ret = iio_device_add_event_sysfs(indio_dev,
513 &indio_dev->channels[j]);
521 static bool iio_check_for_dynamic_events(struct iio_dev *indio_dev)
525 for (j = 0; j < indio_dev->num_channels; j++) {
526 if (indio_dev->channels[j].event_mask != 0)
528 if (indio_dev->channels[j].num_event_specs != 0)
534 static void iio_setup_ev_int(struct iio_event_interface *ev_int)
536 INIT_KFIFO(ev_int->det_events);
537 init_waitqueue_head(&ev_int->wait);
540 static const char *iio_event_group_name = "events";
541 int iio_device_register_eventset(struct iio_dev *indio_dev)
543 struct iio_dev_attr *p;
544 int ret = 0, attrcount_orig = 0, attrcount, attrn;
545 struct attribute **attr;
547 if (!(indio_dev->info->event_attrs ||
548 iio_check_for_dynamic_events(indio_dev)))
551 indio_dev->event_interface =
552 kzalloc(sizeof(struct iio_event_interface), GFP_KERNEL);
553 if (indio_dev->event_interface == NULL) {
558 INIT_LIST_HEAD(&indio_dev->event_interface->dev_attr_list);
560 iio_setup_ev_int(indio_dev->event_interface);
561 if (indio_dev->info->event_attrs != NULL) {
562 attr = indio_dev->info->event_attrs->attrs;
563 while (*attr++ != NULL)
566 attrcount = attrcount_orig;
567 if (indio_dev->channels) {
568 ret = __iio_add_event_config_attrs(indio_dev);
570 goto error_free_setup_event_lines;
574 indio_dev->event_interface->group.name = iio_event_group_name;
575 indio_dev->event_interface->group.attrs = kcalloc(attrcount + 1,
576 sizeof(indio_dev->event_interface->group.attrs[0]),
578 if (indio_dev->event_interface->group.attrs == NULL) {
580 goto error_free_setup_event_lines;
582 if (indio_dev->info->event_attrs)
583 memcpy(indio_dev->event_interface->group.attrs,
584 indio_dev->info->event_attrs->attrs,
585 sizeof(indio_dev->event_interface->group.attrs[0])
587 attrn = attrcount_orig;
588 /* Add all elements from the list. */
589 list_for_each_entry(p,
590 &indio_dev->event_interface->dev_attr_list,
592 indio_dev->event_interface->group.attrs[attrn++] =
594 indio_dev->groups[indio_dev->groupcounter++] =
595 &indio_dev->event_interface->group;
599 error_free_setup_event_lines:
600 iio_free_chan_devattr_list(&indio_dev->event_interface->dev_attr_list);
601 kfree(indio_dev->event_interface);
608 * iio_device_wakeup_eventset - Wakes up the event waitqueue
609 * @indio_dev: The IIO device
611 * Wakes up the event waitqueue used for poll() and blocking read().
612 * Should usually be called when the device is unregistered.
614 void iio_device_wakeup_eventset(struct iio_dev *indio_dev)
616 if (indio_dev->event_interface == NULL)
618 wake_up(&indio_dev->event_interface->wait);
621 void iio_device_unregister_eventset(struct iio_dev *indio_dev)
623 if (indio_dev->event_interface == NULL)
625 iio_free_chan_devattr_list(&indio_dev->event_interface->dev_attr_list);
626 kfree(indio_dev->event_interface->group.attrs);
627 kfree(indio_dev->event_interface);