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",
200 [IIO_EV_TYPE_CHANGE
] = "change",
203 static const char * const iio_ev_dir_text
[] = {
204 [IIO_EV_DIR_EITHER
] = "either",
205 [IIO_EV_DIR_RISING
] = "rising",
206 [IIO_EV_DIR_FALLING
] = "falling"
209 static const char * const iio_ev_info_text
[] = {
210 [IIO_EV_INFO_ENABLE
] = "en",
211 [IIO_EV_INFO_VALUE
] = "value",
212 [IIO_EV_INFO_HYSTERESIS
] = "hysteresis",
213 [IIO_EV_INFO_PERIOD
] = "period",
214 [IIO_EV_INFO_HIGH_PASS_FILTER_3DB
] = "high_pass_filter_3db",
215 [IIO_EV_INFO_LOW_PASS_FILTER_3DB
] = "low_pass_filter_3db",
218 static enum iio_event_direction
iio_ev_attr_dir(struct iio_dev_attr
*attr
)
220 return attr
->c
->event_spec
[attr
->address
& 0xffff].dir
;
223 static enum iio_event_type
iio_ev_attr_type(struct iio_dev_attr
*attr
)
225 return attr
->c
->event_spec
[attr
->address
& 0xffff].type
;
228 static enum iio_event_info
iio_ev_attr_info(struct iio_dev_attr
*attr
)
230 return (attr
->address
>> 16) & 0xffff;
233 static ssize_t
iio_ev_state_store(struct device
*dev
,
234 struct device_attribute
*attr
,
238 struct iio_dev
*indio_dev
= dev_to_iio_dev(dev
);
239 struct iio_dev_attr
*this_attr
= to_iio_dev_attr(attr
);
243 ret
= strtobool(buf
, &val
);
247 ret
= indio_dev
->info
->write_event_config(indio_dev
,
248 this_attr
->c
, iio_ev_attr_type(this_attr
),
249 iio_ev_attr_dir(this_attr
), val
);
251 return (ret
< 0) ? ret
: len
;
254 static ssize_t
iio_ev_state_show(struct device
*dev
,
255 struct device_attribute
*attr
,
258 struct iio_dev
*indio_dev
= dev_to_iio_dev(dev
);
259 struct iio_dev_attr
*this_attr
= to_iio_dev_attr(attr
);
262 val
= indio_dev
->info
->read_event_config(indio_dev
,
263 this_attr
->c
, iio_ev_attr_type(this_attr
),
264 iio_ev_attr_dir(this_attr
));
268 return sprintf(buf
, "%d\n", val
);
271 static ssize_t
iio_ev_value_show(struct device
*dev
,
272 struct device_attribute
*attr
,
275 struct iio_dev
*indio_dev
= dev_to_iio_dev(dev
);
276 struct iio_dev_attr
*this_attr
= to_iio_dev_attr(attr
);
277 int val
, val2
, val_arr
[2];
280 ret
= indio_dev
->info
->read_event_value(indio_dev
,
281 this_attr
->c
, iio_ev_attr_type(this_attr
),
282 iio_ev_attr_dir(this_attr
), iio_ev_attr_info(this_attr
),
288 return iio_format_value(buf
, ret
, 2, val_arr
);
291 static ssize_t
iio_ev_value_store(struct device
*dev
,
292 struct device_attribute
*attr
,
296 struct iio_dev
*indio_dev
= dev_to_iio_dev(dev
);
297 struct iio_dev_attr
*this_attr
= to_iio_dev_attr(attr
);
301 if (!indio_dev
->info
->write_event_value
)
304 ret
= iio_str_to_fixpoint(buf
, 100000, &val
, &val2
);
307 ret
= indio_dev
->info
->write_event_value(indio_dev
,
308 this_attr
->c
, iio_ev_attr_type(this_attr
),
309 iio_ev_attr_dir(this_attr
), iio_ev_attr_info(this_attr
),
317 static int iio_device_add_event(struct iio_dev
*indio_dev
,
318 const struct iio_chan_spec
*chan
, unsigned int spec_index
,
319 enum iio_event_type type
, enum iio_event_direction dir
,
320 enum iio_shared_by shared_by
, const unsigned long *mask
)
322 ssize_t (*show
)(struct device
*, struct device_attribute
*, char *);
323 ssize_t (*store
)(struct device
*, struct device_attribute
*,
324 const char *, size_t);
325 unsigned int attrcount
= 0;
330 for_each_set_bit(i
, mask
, sizeof(*mask
)*8) {
331 if (i
>= ARRAY_SIZE(iio_ev_info_text
))
333 if (dir
!= IIO_EV_DIR_NONE
)
334 postfix
= kasprintf(GFP_KERNEL
, "%s_%s_%s",
335 iio_ev_type_text
[type
],
336 iio_ev_dir_text
[dir
],
337 iio_ev_info_text
[i
]);
339 postfix
= kasprintf(GFP_KERNEL
, "%s_%s",
340 iio_ev_type_text
[type
],
341 iio_ev_info_text
[i
]);
345 if (i
== IIO_EV_INFO_ENABLE
) {
346 show
= iio_ev_state_show
;
347 store
= iio_ev_state_store
;
349 show
= iio_ev_value_show
;
350 store
= iio_ev_value_store
;
353 ret
= __iio_add_chan_devattr(postfix
, chan
, show
, store
,
354 (i
<< 16) | spec_index
, shared_by
, &indio_dev
->dev
,
355 &indio_dev
->event_interface
->dev_attr_list
);
358 if ((ret
== -EBUSY
) && (shared_by
!= IIO_SEPARATE
))
370 static int iio_device_add_event_sysfs(struct iio_dev
*indio_dev
,
371 struct iio_chan_spec
const *chan
)
373 int ret
= 0, i
, attrcount
= 0;
374 enum iio_event_direction dir
;
375 enum iio_event_type type
;
377 for (i
= 0; i
< chan
->num_event_specs
; i
++) {
378 type
= chan
->event_spec
[i
].type
;
379 dir
= chan
->event_spec
[i
].dir
;
381 ret
= iio_device_add_event(indio_dev
, chan
, i
, type
, dir
,
382 IIO_SEPARATE
, &chan
->event_spec
[i
].mask_separate
);
387 ret
= iio_device_add_event(indio_dev
, chan
, i
, type
, dir
,
389 &chan
->event_spec
[i
].mask_shared_by_type
);
394 ret
= iio_device_add_event(indio_dev
, chan
, i
, type
, dir
,
396 &chan
->event_spec
[i
].mask_shared_by_dir
);
401 ret
= iio_device_add_event(indio_dev
, chan
, i
, type
, dir
,
403 &chan
->event_spec
[i
].mask_shared_by_all
);
412 static inline int __iio_add_event_config_attrs(struct iio_dev
*indio_dev
)
414 int j
, ret
, attrcount
= 0;
416 /* Dynamically created from the channels array */
417 for (j
= 0; j
< indio_dev
->num_channels
; j
++) {
418 ret
= iio_device_add_event_sysfs(indio_dev
,
419 &indio_dev
->channels
[j
]);
427 static bool iio_check_for_dynamic_events(struct iio_dev
*indio_dev
)
431 for (j
= 0; j
< indio_dev
->num_channels
; j
++) {
432 if (indio_dev
->channels
[j
].num_event_specs
!= 0)
438 static void iio_setup_ev_int(struct iio_event_interface
*ev_int
)
440 INIT_KFIFO(ev_int
->det_events
);
441 init_waitqueue_head(&ev_int
->wait
);
442 mutex_init(&ev_int
->read_lock
);
445 static const char *iio_event_group_name
= "events";
446 int iio_device_register_eventset(struct iio_dev
*indio_dev
)
448 struct iio_dev_attr
*p
;
449 int ret
= 0, attrcount_orig
= 0, attrcount
, attrn
;
450 struct attribute
**attr
;
452 if (!(indio_dev
->info
->event_attrs
||
453 iio_check_for_dynamic_events(indio_dev
)))
456 indio_dev
->event_interface
=
457 kzalloc(sizeof(struct iio_event_interface
), GFP_KERNEL
);
458 if (indio_dev
->event_interface
== NULL
)
461 INIT_LIST_HEAD(&indio_dev
->event_interface
->dev_attr_list
);
463 iio_setup_ev_int(indio_dev
->event_interface
);
464 if (indio_dev
->info
->event_attrs
!= NULL
) {
465 attr
= indio_dev
->info
->event_attrs
->attrs
;
466 while (*attr
++ != NULL
)
469 attrcount
= attrcount_orig
;
470 if (indio_dev
->channels
) {
471 ret
= __iio_add_event_config_attrs(indio_dev
);
473 goto error_free_setup_event_lines
;
477 indio_dev
->event_interface
->group
.name
= iio_event_group_name
;
478 indio_dev
->event_interface
->group
.attrs
= kcalloc(attrcount
+ 1,
479 sizeof(indio_dev
->event_interface
->group
.attrs
[0]),
481 if (indio_dev
->event_interface
->group
.attrs
== NULL
) {
483 goto error_free_setup_event_lines
;
485 if (indio_dev
->info
->event_attrs
)
486 memcpy(indio_dev
->event_interface
->group
.attrs
,
487 indio_dev
->info
->event_attrs
->attrs
,
488 sizeof(indio_dev
->event_interface
->group
.attrs
[0])
490 attrn
= attrcount_orig
;
491 /* Add all elements from the list. */
492 list_for_each_entry(p
,
493 &indio_dev
->event_interface
->dev_attr_list
,
495 indio_dev
->event_interface
->group
.attrs
[attrn
++] =
497 indio_dev
->groups
[indio_dev
->groupcounter
++] =
498 &indio_dev
->event_interface
->group
;
502 error_free_setup_event_lines
:
503 iio_free_chan_devattr_list(&indio_dev
->event_interface
->dev_attr_list
);
504 kfree(indio_dev
->event_interface
);
505 indio_dev
->event_interface
= NULL
;
510 * iio_device_wakeup_eventset - Wakes up the event waitqueue
511 * @indio_dev: The IIO device
513 * Wakes up the event waitqueue used for poll() and blocking read().
514 * Should usually be called when the device is unregistered.
516 void iio_device_wakeup_eventset(struct iio_dev
*indio_dev
)
518 if (indio_dev
->event_interface
== NULL
)
520 wake_up(&indio_dev
->event_interface
->wait
);
523 void iio_device_unregister_eventset(struct iio_dev
*indio_dev
)
525 if (indio_dev
->event_interface
== NULL
)
527 iio_free_chan_devattr_list(&indio_dev
->event_interface
->dev_attr_list
);
528 kfree(indio_dev
->event_interface
->group
.attrs
);
529 kfree(indio_dev
->event_interface
);