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
;
45 int iio_push_event(struct iio_dev
*indio_dev
, u64 ev_code
, s64 timestamp
)
47 struct iio_event_interface
*ev_int
= indio_dev
->event_interface
;
48 struct iio_event_data ev
;
52 /* Does anyone care? */
53 spin_lock_irqsave(&ev_int
->wait
.lock
, flags
);
54 if (test_bit(IIO_BUSY_BIT_POS
, &ev_int
->flags
)) {
57 ev
.timestamp
= timestamp
;
59 copied
= kfifo_put(&ev_int
->det_events
, &ev
);
61 wake_up_locked_poll(&ev_int
->wait
, POLLIN
);
63 spin_unlock_irqrestore(&ev_int
->wait
.lock
, flags
);
67 EXPORT_SYMBOL(iio_push_event
);
70 * iio_event_poll() - poll the event queue to find out if it has data
72 static unsigned int iio_event_poll(struct file
*filep
,
73 struct poll_table_struct
*wait
)
75 struct iio_event_interface
*ev_int
= filep
->private_data
;
76 unsigned int events
= 0;
78 poll_wait(filep
, &ev_int
->wait
, wait
);
80 spin_lock_irq(&ev_int
->wait
.lock
);
81 if (!kfifo_is_empty(&ev_int
->det_events
))
82 events
= POLLIN
| POLLRDNORM
;
83 spin_unlock_irq(&ev_int
->wait
.lock
);
88 static ssize_t
iio_event_chrdev_read(struct file
*filep
,
93 struct iio_event_interface
*ev_int
= filep
->private_data
;
97 if (count
< sizeof(struct iio_event_data
))
100 spin_lock_irq(&ev_int
->wait
.lock
);
101 if (kfifo_is_empty(&ev_int
->det_events
)) {
102 if (filep
->f_flags
& O_NONBLOCK
) {
106 /* Blocking on device; waiting for something to be there */
107 ret
= wait_event_interruptible_locked_irq(ev_int
->wait
,
108 !kfifo_is_empty(&ev_int
->det_events
));
111 /* Single access device so no one else can get the data */
114 ret
= kfifo_to_user(&ev_int
->det_events
, buf
, count
, &copied
);
117 spin_unlock_irq(&ev_int
->wait
.lock
);
119 return ret
? ret
: copied
;
122 static int iio_event_chrdev_release(struct inode
*inode
, struct file
*filep
)
124 struct iio_event_interface
*ev_int
= filep
->private_data
;
126 spin_lock_irq(&ev_int
->wait
.lock
);
127 __clear_bit(IIO_BUSY_BIT_POS
, &ev_int
->flags
);
129 * In order to maintain a clean state for reopening,
130 * clear out any awaiting events. The mask will prevent
131 * any new __iio_push_event calls running.
133 kfifo_reset_out(&ev_int
->det_events
);
134 spin_unlock_irq(&ev_int
->wait
.lock
);
139 static const struct file_operations iio_event_chrdev_fileops
= {
140 .read
= iio_event_chrdev_read
,
141 .poll
= iio_event_poll
,
142 .release
= iio_event_chrdev_release
,
143 .owner
= THIS_MODULE
,
144 .llseek
= noop_llseek
,
147 int iio_event_getfd(struct iio_dev
*indio_dev
)
149 struct iio_event_interface
*ev_int
= indio_dev
->event_interface
;
155 spin_lock_irq(&ev_int
->wait
.lock
);
156 if (__test_and_set_bit(IIO_BUSY_BIT_POS
, &ev_int
->flags
)) {
157 spin_unlock_irq(&ev_int
->wait
.lock
);
160 spin_unlock_irq(&ev_int
->wait
.lock
);
161 fd
= anon_inode_getfd("iio:event",
162 &iio_event_chrdev_fileops
, ev_int
, O_RDONLY
);
164 spin_lock_irq(&ev_int
->wait
.lock
);
165 __clear_bit(IIO_BUSY_BIT_POS
, &ev_int
->flags
);
166 spin_unlock_irq(&ev_int
->wait
.lock
);
171 static const char * const iio_ev_type_text
[] = {
172 [IIO_EV_TYPE_THRESH
] = "thresh",
173 [IIO_EV_TYPE_MAG
] = "mag",
174 [IIO_EV_TYPE_ROC
] = "roc",
175 [IIO_EV_TYPE_THRESH_ADAPTIVE
] = "thresh_adaptive",
176 [IIO_EV_TYPE_MAG_ADAPTIVE
] = "mag_adaptive",
179 static const char * const iio_ev_dir_text
[] = {
180 [IIO_EV_DIR_EITHER
] = "either",
181 [IIO_EV_DIR_RISING
] = "rising",
182 [IIO_EV_DIR_FALLING
] = "falling"
185 static ssize_t
iio_ev_state_store(struct device
*dev
,
186 struct device_attribute
*attr
,
190 struct iio_dev
*indio_dev
= dev_to_iio_dev(dev
);
191 struct iio_dev_attr
*this_attr
= to_iio_dev_attr(attr
);
195 ret
= strtobool(buf
, &val
);
199 ret
= indio_dev
->info
->write_event_config(indio_dev
,
202 return (ret
< 0) ? ret
: len
;
205 static ssize_t
iio_ev_state_show(struct device
*dev
,
206 struct device_attribute
*attr
,
209 struct iio_dev
*indio_dev
= dev_to_iio_dev(dev
);
210 struct iio_dev_attr
*this_attr
= to_iio_dev_attr(attr
);
211 int val
= indio_dev
->info
->read_event_config(indio_dev
,
217 return sprintf(buf
, "%d\n", val
);
220 static ssize_t
iio_ev_value_show(struct device
*dev
,
221 struct device_attribute
*attr
,
224 struct iio_dev
*indio_dev
= dev_to_iio_dev(dev
);
225 struct iio_dev_attr
*this_attr
= to_iio_dev_attr(attr
);
228 ret
= indio_dev
->info
->read_event_value(indio_dev
,
229 this_attr
->address
, &val
);
233 return sprintf(buf
, "%d\n", val
);
236 static ssize_t
iio_ev_value_store(struct device
*dev
,
237 struct device_attribute
*attr
,
241 struct iio_dev
*indio_dev
= dev_to_iio_dev(dev
);
242 struct iio_dev_attr
*this_attr
= to_iio_dev_attr(attr
);
246 if (!indio_dev
->info
->write_event_value
)
249 ret
= kstrtoint(buf
, 10, &val
);
253 ret
= indio_dev
->info
->write_event_value(indio_dev
, this_attr
->address
,
261 static int iio_device_add_event_sysfs(struct iio_dev
*indio_dev
,
262 struct iio_chan_spec
const *chan
)
264 int ret
= 0, i
, attrcount
= 0;
267 if (!chan
->event_mask
)
270 for_each_set_bit(i
, &chan
->event_mask
, sizeof(chan
->event_mask
)*8) {
271 postfix
= kasprintf(GFP_KERNEL
, "%s_%s_en",
272 iio_ev_type_text
[i
/IIO_EV_DIR_MAX
],
273 iio_ev_dir_text
[i
%IIO_EV_DIR_MAX
]);
274 if (postfix
== NULL
) {
279 mask
= IIO_MOD_EVENT_CODE(chan
->type
, 0, chan
->channel
,
282 else if (chan
->differential
)
283 mask
= IIO_EVENT_CODE(chan
->type
,
291 mask
= IIO_UNMOD_EVENT_CODE(chan
->type
,
296 ret
= __iio_add_chan_devattr(postfix
,
303 &indio_dev
->event_interface
->
309 postfix
= kasprintf(GFP_KERNEL
, "%s_%s_value",
310 iio_ev_type_text
[i
/IIO_EV_DIR_MAX
],
311 iio_ev_dir_text
[i
%IIO_EV_DIR_MAX
]);
312 if (postfix
== NULL
) {
316 ret
= __iio_add_chan_devattr(postfix
, chan
,
322 &indio_dev
->event_interface
->
334 static inline void __iio_remove_event_config_attrs(struct iio_dev
*indio_dev
)
336 struct iio_dev_attr
*p
, *n
;
337 list_for_each_entry_safe(p
, n
,
338 &indio_dev
->event_interface
->
340 kfree(p
->dev_attr
.attr
.name
);
345 static inline int __iio_add_event_config_attrs(struct iio_dev
*indio_dev
)
347 int j
, ret
, attrcount
= 0;
349 /* Dynically created from the channels array */
350 for (j
= 0; j
< indio_dev
->num_channels
; j
++) {
351 ret
= iio_device_add_event_sysfs(indio_dev
,
352 &indio_dev
->channels
[j
]);
360 static bool iio_check_for_dynamic_events(struct iio_dev
*indio_dev
)
364 for (j
= 0; j
< indio_dev
->num_channels
; j
++)
365 if (indio_dev
->channels
[j
].event_mask
!= 0)
370 static void iio_setup_ev_int(struct iio_event_interface
*ev_int
)
372 INIT_KFIFO(ev_int
->det_events
);
373 init_waitqueue_head(&ev_int
->wait
);
376 static const char *iio_event_group_name
= "events";
377 int iio_device_register_eventset(struct iio_dev
*indio_dev
)
379 struct iio_dev_attr
*p
;
380 int ret
= 0, attrcount_orig
= 0, attrcount
, attrn
;
381 struct attribute
**attr
;
383 if (!(indio_dev
->info
->event_attrs
||
384 iio_check_for_dynamic_events(indio_dev
)))
387 indio_dev
->event_interface
=
388 kzalloc(sizeof(struct iio_event_interface
), GFP_KERNEL
);
389 if (indio_dev
->event_interface
== NULL
) {
394 INIT_LIST_HEAD(&indio_dev
->event_interface
->dev_attr_list
);
396 iio_setup_ev_int(indio_dev
->event_interface
);
397 if (indio_dev
->info
->event_attrs
!= NULL
) {
398 attr
= indio_dev
->info
->event_attrs
->attrs
;
399 while (*attr
++ != NULL
)
402 attrcount
= attrcount_orig
;
403 if (indio_dev
->channels
) {
404 ret
= __iio_add_event_config_attrs(indio_dev
);
406 goto error_free_setup_event_lines
;
410 indio_dev
->event_interface
->group
.name
= iio_event_group_name
;
411 indio_dev
->event_interface
->group
.attrs
= kcalloc(attrcount
+ 1,
412 sizeof(indio_dev
->event_interface
->group
.attrs
[0]),
414 if (indio_dev
->event_interface
->group
.attrs
== NULL
) {
416 goto error_free_setup_event_lines
;
418 if (indio_dev
->info
->event_attrs
)
419 memcpy(indio_dev
->event_interface
->group
.attrs
,
420 indio_dev
->info
->event_attrs
->attrs
,
421 sizeof(indio_dev
->event_interface
->group
.attrs
[0])
423 attrn
= attrcount_orig
;
424 /* Add all elements from the list. */
425 list_for_each_entry(p
,
426 &indio_dev
->event_interface
->dev_attr_list
,
428 indio_dev
->event_interface
->group
.attrs
[attrn
++] =
430 indio_dev
->groups
[indio_dev
->groupcounter
++] =
431 &indio_dev
->event_interface
->group
;
435 error_free_setup_event_lines
:
436 __iio_remove_event_config_attrs(indio_dev
);
437 kfree(indio_dev
->event_interface
);
443 void iio_device_unregister_eventset(struct iio_dev
*indio_dev
)
445 if (indio_dev
->event_interface
== NULL
)
447 __iio_remove_event_config_attrs(indio_dev
);
448 kfree(indio_dev
->event_interface
->group
.attrs
);
449 kfree(indio_dev
->event_interface
);