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;
43 struct mutex read_lock;
47 * iio_push_event() - try to add event to the list for userspace reading
48 * @indio_dev: IIO device structure
49 * @ev_code: What event
50 * @timestamp: When the event occurred
52 * Note: The caller must make sure that this function is not running
53 * concurrently for the same indio_dev more than once.
55 int iio_push_event(struct iio_dev *indio_dev, u64 ev_code, s64 timestamp)
57 struct iio_event_interface *ev_int = indio_dev->event_interface;
58 struct iio_event_data ev;
61 /* Does anyone care? */
62 if (test_bit(IIO_BUSY_BIT_POS, &ev_int->flags)) {
65 ev.timestamp = timestamp;
67 copied = kfifo_put(&ev_int->det_events, ev);
69 wake_up_poll(&ev_int->wait, POLLIN);
74 EXPORT_SYMBOL(iio_push_event);
77 * iio_event_poll() - poll the event queue to find out if it has data
79 static unsigned int iio_event_poll(struct file *filep,
80 struct poll_table_struct *wait)
82 struct iio_dev *indio_dev = filep->private_data;
83 struct iio_event_interface *ev_int = indio_dev->event_interface;
84 unsigned int events = 0;
89 poll_wait(filep, &ev_int->wait, wait);
91 if (!kfifo_is_empty(&ev_int->det_events))
92 events = POLLIN | POLLRDNORM;
97 static ssize_t iio_event_chrdev_read(struct file *filep,
102 struct iio_dev *indio_dev = filep->private_data;
103 struct iio_event_interface *ev_int = indio_dev->event_interface;
107 if (!indio_dev->info)
110 if (count < sizeof(struct iio_event_data))
114 if (kfifo_is_empty(&ev_int->det_events)) {
115 if (filep->f_flags & O_NONBLOCK)
118 ret = wait_event_interruptible(ev_int->wait,
119 !kfifo_is_empty(&ev_int->det_events) ||
120 indio_dev->info == NULL);
123 if (indio_dev->info == NULL)
127 if (mutex_lock_interruptible(&ev_int->read_lock))
129 ret = kfifo_to_user(&ev_int->det_events, buf, count, &copied);
130 mutex_unlock(&ev_int->read_lock);
136 * If we couldn't read anything from the fifo (a different
137 * thread might have been faster) we either return -EAGAIN if
138 * the file descriptor is non-blocking, otherwise we go back to
139 * sleep and wait for more data to arrive.
141 if (copied == 0 && (filep->f_flags & O_NONBLOCK))
144 } while (copied == 0);
149 static int iio_event_chrdev_release(struct inode *inode, struct file *filep)
151 struct iio_dev *indio_dev = filep->private_data;
152 struct iio_event_interface *ev_int = indio_dev->event_interface;
154 clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags);
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 if (test_and_set_bit(IIO_BUSY_BIT_POS, &ev_int->flags))
180 iio_device_get(indio_dev);
182 fd = anon_inode_getfd("iio:event", &iio_event_chrdev_fileops,
183 indio_dev, O_RDONLY | O_CLOEXEC);
185 clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags);
186 iio_device_put(indio_dev);
188 kfifo_reset_out(&ev_int->det_events);
194 static const char * const iio_ev_type_text[] = {
195 [IIO_EV_TYPE_THRESH] = "thresh",
196 [IIO_EV_TYPE_MAG] = "mag",
197 [IIO_EV_TYPE_ROC] = "roc",
198 [IIO_EV_TYPE_THRESH_ADAPTIVE] = "thresh_adaptive",
199 [IIO_EV_TYPE_MAG_ADAPTIVE] = "mag_adaptive",
202 static const char * const iio_ev_dir_text[] = {
203 [IIO_EV_DIR_EITHER] = "either",
204 [IIO_EV_DIR_RISING] = "rising",
205 [IIO_EV_DIR_FALLING] = "falling"
208 static const char * const iio_ev_info_text[] = {
209 [IIO_EV_INFO_ENABLE] = "en",
210 [IIO_EV_INFO_VALUE] = "value",
211 [IIO_EV_INFO_HYSTERESIS] = "hysteresis",
214 static enum iio_event_direction iio_ev_attr_dir(struct iio_dev_attr *attr)
216 return attr->c->event_spec[attr->address & 0xffff].dir;
219 static enum iio_event_type iio_ev_attr_type(struct iio_dev_attr *attr)
221 return attr->c->event_spec[attr->address & 0xffff].type;
224 static enum iio_event_info iio_ev_attr_info(struct iio_dev_attr *attr)
226 return (attr->address >> 16) & 0xffff;
229 static ssize_t iio_ev_state_store(struct device *dev,
230 struct device_attribute *attr,
234 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
235 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
239 ret = strtobool(buf, &val);
243 ret = indio_dev->info->write_event_config(indio_dev,
244 this_attr->c, iio_ev_attr_type(this_attr),
245 iio_ev_attr_dir(this_attr), val);
247 return (ret < 0) ? ret : len;
250 static ssize_t iio_ev_state_show(struct device *dev,
251 struct device_attribute *attr,
254 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
255 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
258 val = indio_dev->info->read_event_config(indio_dev,
259 this_attr->c, iio_ev_attr_type(this_attr),
260 iio_ev_attr_dir(this_attr));
264 return sprintf(buf, "%d\n", val);
267 static ssize_t iio_ev_value_show(struct device *dev,
268 struct device_attribute *attr,
271 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
272 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
276 ret = indio_dev->info->read_event_value(indio_dev,
277 this_attr->c, iio_ev_attr_type(this_attr),
278 iio_ev_attr_dir(this_attr), iio_ev_attr_info(this_attr),
282 return iio_format_value(buf, ret, val, val2);
285 static ssize_t iio_ev_value_store(struct device *dev,
286 struct device_attribute *attr,
290 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
291 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
295 if (!indio_dev->info->write_event_value)
298 ret = iio_str_to_fixpoint(buf, 100000, &val, &val2);
301 ret = indio_dev->info->write_event_value(indio_dev,
302 this_attr->c, iio_ev_attr_type(this_attr),
303 iio_ev_attr_dir(this_attr), iio_ev_attr_info(this_attr),
311 static int iio_device_add_event(struct iio_dev *indio_dev,
312 const struct iio_chan_spec *chan, unsigned int spec_index,
313 enum iio_event_type type, enum iio_event_direction dir,
314 enum iio_shared_by shared_by, const unsigned long *mask)
316 ssize_t (*show)(struct device *, struct device_attribute *, char *);
317 ssize_t (*store)(struct device *, struct device_attribute *,
318 const char *, size_t);
319 unsigned int attrcount = 0;
324 for_each_set_bit(i, mask, sizeof(*mask)) {
325 postfix = kasprintf(GFP_KERNEL, "%s_%s_%s",
326 iio_ev_type_text[type], iio_ev_dir_text[dir],
327 iio_ev_info_text[i]);
331 if (i == IIO_EV_INFO_ENABLE) {
332 show = iio_ev_state_show;
333 store = iio_ev_state_store;
335 show = iio_ev_value_show;
336 store = iio_ev_value_store;
339 ret = __iio_add_chan_devattr(postfix, chan, show, store,
340 (i << 16) | spec_index, shared_by, &indio_dev->dev,
341 &indio_dev->event_interface->dev_attr_list);
353 static int iio_device_add_event_sysfs(struct iio_dev *indio_dev,
354 struct iio_chan_spec const *chan)
356 int ret = 0, i, attrcount = 0;
357 enum iio_event_direction dir;
358 enum iio_event_type type;
360 for (i = 0; i < chan->num_event_specs; i++) {
361 type = chan->event_spec[i].type;
362 dir = chan->event_spec[i].dir;
364 ret = iio_device_add_event(indio_dev, chan, i, type, dir,
365 IIO_SEPARATE, &chan->event_spec[i].mask_separate);
370 ret = iio_device_add_event(indio_dev, chan, i, type, dir,
372 &chan->event_spec[i].mask_shared_by_type);
377 ret = iio_device_add_event(indio_dev, chan, i, type, dir,
379 &chan->event_spec[i].mask_shared_by_dir);
384 ret = iio_device_add_event(indio_dev, chan, i, type, dir,
386 &chan->event_spec[i].mask_shared_by_all);
395 static inline int __iio_add_event_config_attrs(struct iio_dev *indio_dev)
397 int j, ret, attrcount = 0;
399 /* Dynically created from the channels array */
400 for (j = 0; j < indio_dev->num_channels; j++) {
401 ret = iio_device_add_event_sysfs(indio_dev,
402 &indio_dev->channels[j]);
410 static bool iio_check_for_dynamic_events(struct iio_dev *indio_dev)
414 for (j = 0; j < indio_dev->num_channels; j++) {
415 if (indio_dev->channels[j].num_event_specs != 0)
421 static void iio_setup_ev_int(struct iio_event_interface *ev_int)
423 INIT_KFIFO(ev_int->det_events);
424 init_waitqueue_head(&ev_int->wait);
425 mutex_init(&ev_int->read_lock);
428 static const char *iio_event_group_name = "events";
429 int iio_device_register_eventset(struct iio_dev *indio_dev)
431 struct iio_dev_attr *p;
432 int ret = 0, attrcount_orig = 0, attrcount, attrn;
433 struct attribute **attr;
435 if (!(indio_dev->info->event_attrs ||
436 iio_check_for_dynamic_events(indio_dev)))
439 indio_dev->event_interface =
440 kzalloc(sizeof(struct iio_event_interface), GFP_KERNEL);
441 if (indio_dev->event_interface == NULL)
444 INIT_LIST_HEAD(&indio_dev->event_interface->dev_attr_list);
446 iio_setup_ev_int(indio_dev->event_interface);
447 if (indio_dev->info->event_attrs != NULL) {
448 attr = indio_dev->info->event_attrs->attrs;
449 while (*attr++ != NULL)
452 attrcount = attrcount_orig;
453 if (indio_dev->channels) {
454 ret = __iio_add_event_config_attrs(indio_dev);
456 goto error_free_setup_event_lines;
460 indio_dev->event_interface->group.name = iio_event_group_name;
461 indio_dev->event_interface->group.attrs = kcalloc(attrcount + 1,
462 sizeof(indio_dev->event_interface->group.attrs[0]),
464 if (indio_dev->event_interface->group.attrs == NULL) {
466 goto error_free_setup_event_lines;
468 if (indio_dev->info->event_attrs)
469 memcpy(indio_dev->event_interface->group.attrs,
470 indio_dev->info->event_attrs->attrs,
471 sizeof(indio_dev->event_interface->group.attrs[0])
473 attrn = attrcount_orig;
474 /* Add all elements from the list. */
475 list_for_each_entry(p,
476 &indio_dev->event_interface->dev_attr_list,
478 indio_dev->event_interface->group.attrs[attrn++] =
480 indio_dev->groups[indio_dev->groupcounter++] =
481 &indio_dev->event_interface->group;
485 error_free_setup_event_lines:
486 iio_free_chan_devattr_list(&indio_dev->event_interface->dev_attr_list);
487 kfree(indio_dev->event_interface);
492 * iio_device_wakeup_eventset - Wakes up the event waitqueue
493 * @indio_dev: The IIO device
495 * Wakes up the event waitqueue used for poll() and blocking read().
496 * Should usually be called when the device is unregistered.
498 void iio_device_wakeup_eventset(struct iio_dev *indio_dev)
500 if (indio_dev->event_interface == NULL)
502 wake_up(&indio_dev->event_interface->wait);
505 void iio_device_unregister_eventset(struct iio_dev *indio_dev)
507 if (indio_dev->event_interface == NULL)
509 iio_free_chan_devattr_list(&indio_dev->event_interface->dev_attr_list);
510 kfree(indio_dev->event_interface->group.attrs);
511 kfree(indio_dev->event_interface);