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1/* Industrial I/O event handling
2 *
3 * Copyright (c) 2008 Jonathan Cameron
4 *
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.
8 *
9 * Based on elements of hwmon and input subsystems.
10 */
11
12#include <linux/anon_inodes.h>
13#include <linux/device.h>
14#include <linux/fs.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>
24#include "iio_core.h"
25#include <linux/iio/sysfs.h>
26#include <linux/iio/events.h>
27
28/**
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 */
36struct iio_event_interface {
37 wait_queue_head_t wait;
38 DECLARE_KFIFO(det_events, struct iio_event_data, 16);
39
40 struct list_head dev_attr_list;
41 unsigned long flags;
42 struct attribute_group group;
43};
44
45int iio_push_event(struct iio_dev *indio_dev, u64 ev_code, s64 timestamp)
46{
47 struct iio_event_interface *ev_int = indio_dev->event_interface;
48 struct iio_event_data ev;
49 int copied;
50
51 /* Does anyone care? */
52 spin_lock(&ev_int->wait.lock);
53 if (test_bit(IIO_BUSY_BIT_POS, &ev_int->flags)) {
54
55 ev.id = ev_code;
56 ev.timestamp = timestamp;
57
58 copied = kfifo_put(&ev_int->det_events, &ev);
59 if (copied != 0)
60 wake_up_locked_poll(&ev_int->wait, POLLIN);
61 }
62 spin_unlock(&ev_int->wait.lock);
63
64 return 0;
65}
66EXPORT_SYMBOL(iio_push_event);
67
68/**
69 * iio_event_poll() - poll the event queue to find out if it has data
70 */
71static unsigned int iio_event_poll(struct file *filep,
72 struct poll_table_struct *wait)
73{
74 struct iio_event_interface *ev_int = filep->private_data;
75 unsigned int events = 0;
76
77 poll_wait(filep, &ev_int->wait, wait);
78
79 spin_lock(&ev_int->wait.lock);
80 if (!kfifo_is_empty(&ev_int->det_events))
81 events = POLLIN | POLLRDNORM;
82 spin_unlock(&ev_int->wait.lock);
83
84 return events;
85}
86
87static ssize_t iio_event_chrdev_read(struct file *filep,
88 char __user *buf,
89 size_t count,
90 loff_t *f_ps)
91{
92 struct iio_event_interface *ev_int = filep->private_data;
93 unsigned int copied;
94 int ret;
95
96 if (count < sizeof(struct iio_event_data))
97 return -EINVAL;
98
99 spin_lock(&ev_int->wait.lock);
100 if (kfifo_is_empty(&ev_int->det_events)) {
101 if (filep->f_flags & O_NONBLOCK) {
102 ret = -EAGAIN;
103 goto error_unlock;
104 }
105 /* Blocking on device; waiting for something to be there */
106 ret = wait_event_interruptible_locked(ev_int->wait,
107 !kfifo_is_empty(&ev_int->det_events));
108 if (ret)
109 goto error_unlock;
110 /* Single access device so no one else can get the data */
111 }
112
113 ret = kfifo_to_user(&ev_int->det_events, buf, count, &copied);
114
115error_unlock:
116 spin_unlock(&ev_int->wait.lock);
117
118 return ret ? ret : copied;
119}
120
121static int iio_event_chrdev_release(struct inode *inode, struct file *filep)
122{
123 struct iio_event_interface *ev_int = filep->private_data;
124
125 spin_lock(&ev_int->wait.lock);
126 __clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags);
127 /*
128 * In order to maintain a clean state for reopening,
129 * clear out any awaiting events. The mask will prevent
130 * any new __iio_push_event calls running.
131 */
132 kfifo_reset_out(&ev_int->det_events);
133 spin_unlock(&ev_int->wait.lock);
134
135 return 0;
136}
137
138static const struct file_operations iio_event_chrdev_fileops = {
139 .read = iio_event_chrdev_read,
140 .poll = iio_event_poll,
141 .release = iio_event_chrdev_release,
142 .owner = THIS_MODULE,
143 .llseek = noop_llseek,
144};
145
146int iio_event_getfd(struct iio_dev *indio_dev)
147{
148 struct iio_event_interface *ev_int = indio_dev->event_interface;
149 int fd;
150
151 if (ev_int == NULL)
152 return -ENODEV;
153
154 spin_lock(&ev_int->wait.lock);
155 if (__test_and_set_bit(IIO_BUSY_BIT_POS, &ev_int->flags)) {
156 spin_unlock(&ev_int->wait.lock);
157 return -EBUSY;
158 }
159 spin_unlock(&ev_int->wait.lock);
160 fd = anon_inode_getfd("iio:event",
161 &iio_event_chrdev_fileops, ev_int, O_RDONLY);
162 if (fd < 0) {
163 spin_lock(&ev_int->wait.lock);
164 __clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags);
165 spin_unlock(&ev_int->wait.lock);
166 }
167 return fd;
168}
169
170static const char * const iio_ev_type_text[] = {
171 [IIO_EV_TYPE_THRESH] = "thresh",
172 [IIO_EV_TYPE_MAG] = "mag",
173 [IIO_EV_TYPE_ROC] = "roc",
174 [IIO_EV_TYPE_THRESH_ADAPTIVE] = "thresh_adaptive",
175 [IIO_EV_TYPE_MAG_ADAPTIVE] = "mag_adaptive",
176};
177
178static const char * const iio_ev_dir_text[] = {
179 [IIO_EV_DIR_EITHER] = "either",
180 [IIO_EV_DIR_RISING] = "rising",
181 [IIO_EV_DIR_FALLING] = "falling"
182};
183
184static ssize_t iio_ev_state_store(struct device *dev,
185 struct device_attribute *attr,
186 const char *buf,
187 size_t len)
188{
189 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
190 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
191 int ret;
192 bool val;
193
194 ret = strtobool(buf, &val);
195 if (ret < 0)
196 return ret;
197
198 ret = indio_dev->info->write_event_config(indio_dev,
199 this_attr->address,
200 val);
201 return (ret < 0) ? ret : len;
202}
203
204static ssize_t iio_ev_state_show(struct device *dev,
205 struct device_attribute *attr,
206 char *buf)
207{
208 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
209 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
210 int val = indio_dev->info->read_event_config(indio_dev,
211 this_attr->address);
212
213 if (val < 0)
214 return val;
215 else
216 return sprintf(buf, "%d\n", val);
217}
218
219static ssize_t iio_ev_value_show(struct device *dev,
220 struct device_attribute *attr,
221 char *buf)
222{
223 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
224 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
225 int val, ret;
226
227 ret = indio_dev->info->read_event_value(indio_dev,
228 this_attr->address, &val);
229 if (ret < 0)
230 return ret;
231
232 return sprintf(buf, "%d\n", val);
233}
234
235static ssize_t iio_ev_value_store(struct device *dev,
236 struct device_attribute *attr,
237 const char *buf,
238 size_t len)
239{
240 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
241 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
242 unsigned long val;
243 int ret;
244
245 if (!indio_dev->info->write_event_value)
246 return -EINVAL;
247
248 ret = strict_strtoul(buf, 10, &val);
249 if (ret)
250 return ret;
251
252 ret = indio_dev->info->write_event_value(indio_dev, this_attr->address,
253 val);
254 if (ret < 0)
255 return ret;
256
257 return len;
258}
259
260static int iio_device_add_event_sysfs(struct iio_dev *indio_dev,
261 struct iio_chan_spec const *chan)
262{
263 int ret = 0, i, attrcount = 0;
264 u64 mask = 0;
265 char *postfix;
266 if (!chan->event_mask)
267 return 0;
268
269 for_each_set_bit(i, &chan->event_mask, sizeof(chan->event_mask)*8) {
270 postfix = kasprintf(GFP_KERNEL, "%s_%s_en",
271 iio_ev_type_text[i/IIO_EV_DIR_MAX],
272 iio_ev_dir_text[i%IIO_EV_DIR_MAX]);
273 if (postfix == NULL) {
274 ret = -ENOMEM;
275 goto error_ret;
276 }
277 if (chan->modified)
278 mask = IIO_MOD_EVENT_CODE(chan->type, 0, chan->channel,
279 i/IIO_EV_DIR_MAX,
280 i%IIO_EV_DIR_MAX);
281 else if (chan->differential)
282 mask = IIO_EVENT_CODE(chan->type,
283 0, 0,
284 i%IIO_EV_DIR_MAX,
285 i/IIO_EV_DIR_MAX,
286 0,
287 chan->channel,
288 chan->channel2);
289 else
290 mask = IIO_UNMOD_EVENT_CODE(chan->type,
291 chan->channel,
292 i/IIO_EV_DIR_MAX,
293 i%IIO_EV_DIR_MAX);
294
295 ret = __iio_add_chan_devattr(postfix,
296 chan,
297 &iio_ev_state_show,
298 iio_ev_state_store,
299 mask,
300 0,
301 &indio_dev->dev,
302 &indio_dev->event_interface->
303 dev_attr_list);
304 kfree(postfix);
305 if (ret)
306 goto error_ret;
307 attrcount++;
308 postfix = kasprintf(GFP_KERNEL, "%s_%s_value",
309 iio_ev_type_text[i/IIO_EV_DIR_MAX],
310 iio_ev_dir_text[i%IIO_EV_DIR_MAX]);
311 if (postfix == NULL) {
312 ret = -ENOMEM;
313 goto error_ret;
314 }
315 ret = __iio_add_chan_devattr(postfix, chan,
316 iio_ev_value_show,
317 iio_ev_value_store,
318 mask,
319 0,
320 &indio_dev->dev,
321 &indio_dev->event_interface->
322 dev_attr_list);
323 kfree(postfix);
324 if (ret)
325 goto error_ret;
326 attrcount++;
327 }
328 ret = attrcount;
329error_ret:
330 return ret;
331}
332
333static inline void __iio_remove_event_config_attrs(struct iio_dev *indio_dev)
334{
335 struct iio_dev_attr *p, *n;
336 list_for_each_entry_safe(p, n,
337 &indio_dev->event_interface->
338 dev_attr_list, l) {
339 kfree(p->dev_attr.attr.name);
340 kfree(p);
341 }
342}
343
344static inline int __iio_add_event_config_attrs(struct iio_dev *indio_dev)
345{
346 int j, ret, attrcount = 0;
347
348 INIT_LIST_HEAD(&indio_dev->event_interface->dev_attr_list);
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]);
353 if (ret < 0)
354 goto error_clear_attrs;
355 attrcount += ret;
356 }
357 return attrcount;
358
359error_clear_attrs:
360 __iio_remove_event_config_attrs(indio_dev);
361
362 return ret;
363}
364
365static bool iio_check_for_dynamic_events(struct iio_dev *indio_dev)
366{
367 int j;
368
369 for (j = 0; j < indio_dev->num_channels; j++)
370 if (indio_dev->channels[j].event_mask != 0)
371 return true;
372 return false;
373}
374
375static void iio_setup_ev_int(struct iio_event_interface *ev_int)
376{
377 INIT_KFIFO(ev_int->det_events);
378 init_waitqueue_head(&ev_int->wait);
379}
380
381static const char *iio_event_group_name = "events";
382int iio_device_register_eventset(struct iio_dev *indio_dev)
383{
384 struct iio_dev_attr *p;
385 int ret = 0, attrcount_orig = 0, attrcount, attrn;
386 struct attribute **attr;
387
388 if (!(indio_dev->info->event_attrs ||
389 iio_check_for_dynamic_events(indio_dev)))
390 return 0;
391
392 indio_dev->event_interface =
393 kzalloc(sizeof(struct iio_event_interface), GFP_KERNEL);
394 if (indio_dev->event_interface == NULL) {
395 ret = -ENOMEM;
396 goto error_ret;
397 }
398
399 iio_setup_ev_int(indio_dev->event_interface);
400 if (indio_dev->info->event_attrs != NULL) {
401 attr = indio_dev->info->event_attrs->attrs;
402 while (*attr++ != NULL)
403 attrcount_orig++;
404 }
405 attrcount = attrcount_orig;
406 if (indio_dev->channels) {
407 ret = __iio_add_event_config_attrs(indio_dev);
408 if (ret < 0)
409 goto error_free_setup_event_lines;
410 attrcount += ret;
411 }
412
413 indio_dev->event_interface->group.name = iio_event_group_name;
414 indio_dev->event_interface->group.attrs = kcalloc(attrcount + 1,
415 sizeof(indio_dev->event_interface->group.attrs[0]),
416 GFP_KERNEL);
417 if (indio_dev->event_interface->group.attrs == NULL) {
418 ret = -ENOMEM;
419 goto error_free_setup_event_lines;
420 }
421 if (indio_dev->info->event_attrs)
422 memcpy(indio_dev->event_interface->group.attrs,
423 indio_dev->info->event_attrs->attrs,
424 sizeof(indio_dev->event_interface->group.attrs[0])
425 *attrcount_orig);
426 attrn = attrcount_orig;
427 /* Add all elements from the list. */
428 list_for_each_entry(p,
429 &indio_dev->event_interface->dev_attr_list,
430 l)
431 indio_dev->event_interface->group.attrs[attrn++] =
432 &p->dev_attr.attr;
433 indio_dev->groups[indio_dev->groupcounter++] =
434 &indio_dev->event_interface->group;
435
436 return 0;
437
438error_free_setup_event_lines:
439 __iio_remove_event_config_attrs(indio_dev);
440 kfree(indio_dev->event_interface);
441error_ret:
442
443 return ret;
444}
445
446void iio_device_unregister_eventset(struct iio_dev *indio_dev)
447{
448 if (indio_dev->event_interface == NULL)
449 return;
450 __iio_remove_event_config_attrs(indio_dev);
451 kfree(indio_dev->event_interface->group.attrs);
452 kfree(indio_dev->event_interface);
453}