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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 | */ | |
36 | struct 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 | ||
45 | int 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 | unsigned long flags; | |
50 | int copied; | |
51 | ||
52 | /* Does anyone care? */ | |
53 | spin_lock_irqsave(&ev_int->wait.lock, flags); | |
54 | if (test_bit(IIO_BUSY_BIT_POS, &ev_int->flags)) { | |
55 | ||
56 | ev.id = ev_code; | |
57 | ev.timestamp = timestamp; | |
58 | ||
59 | copied = kfifo_put(&ev_int->det_events, &ev); | |
60 | if (copied != 0) | |
61 | wake_up_locked_poll(&ev_int->wait, POLLIN); | |
62 | } | |
63 | spin_unlock_irqrestore(&ev_int->wait.lock, flags); | |
64 | ||
65 | return 0; | |
66 | } | |
67 | EXPORT_SYMBOL(iio_push_event); | |
68 | ||
69 | /** | |
70 | * iio_event_poll() - poll the event queue to find out if it has data | |
71 | */ | |
72 | static unsigned int iio_event_poll(struct file *filep, | |
73 | struct poll_table_struct *wait) | |
74 | { | |
75 | struct iio_dev *indio_dev = filep->private_data; | |
76 | struct iio_event_interface *ev_int = indio_dev->event_interface; | |
77 | unsigned int events = 0; | |
78 | ||
79 | poll_wait(filep, &ev_int->wait, wait); | |
80 | ||
81 | spin_lock_irq(&ev_int->wait.lock); | |
82 | if (!kfifo_is_empty(&ev_int->det_events)) | |
83 | events = POLLIN | POLLRDNORM; | |
84 | spin_unlock_irq(&ev_int->wait.lock); | |
85 | ||
86 | return events; | |
87 | } | |
88 | ||
89 | static ssize_t iio_event_chrdev_read(struct file *filep, | |
90 | char __user *buf, | |
91 | size_t count, | |
92 | loff_t *f_ps) | |
93 | { | |
94 | struct iio_dev *indio_dev = filep->private_data; | |
95 | struct iio_event_interface *ev_int = indio_dev->event_interface; | |
96 | unsigned int copied; | |
97 | int ret; | |
98 | ||
99 | if (count < sizeof(struct iio_event_data)) | |
100 | return -EINVAL; | |
101 | ||
102 | spin_lock_irq(&ev_int->wait.lock); | |
103 | if (kfifo_is_empty(&ev_int->det_events)) { | |
104 | if (filep->f_flags & O_NONBLOCK) { | |
105 | ret = -EAGAIN; | |
106 | goto error_unlock; | |
107 | } | |
108 | /* Blocking on device; waiting for something to be there */ | |
109 | ret = wait_event_interruptible_locked_irq(ev_int->wait, | |
110 | !kfifo_is_empty(&ev_int->det_events)); | |
111 | if (ret) | |
112 | goto error_unlock; | |
113 | /* Single access device so no one else can get the data */ | |
114 | } | |
115 | ||
116 | ret = kfifo_to_user(&ev_int->det_events, buf, count, &copied); | |
117 | ||
118 | error_unlock: | |
119 | spin_unlock_irq(&ev_int->wait.lock); | |
120 | ||
121 | return ret ? ret : copied; | |
122 | } | |
123 | ||
124 | static int iio_event_chrdev_release(struct inode *inode, struct file *filep) | |
125 | { | |
126 | struct iio_dev *indio_dev = filep->private_data; | |
127 | struct iio_event_interface *ev_int = indio_dev->event_interface; | |
128 | ||
129 | spin_lock_irq(&ev_int->wait.lock); | |
130 | __clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags); | |
131 | /* | |
132 | * In order to maintain a clean state for reopening, | |
133 | * clear out any awaiting events. The mask will prevent | |
134 | * any new __iio_push_event calls running. | |
135 | */ | |
136 | kfifo_reset_out(&ev_int->det_events); | |
137 | spin_unlock_irq(&ev_int->wait.lock); | |
138 | ||
139 | iio_device_put(indio_dev); | |
140 | ||
141 | return 0; | |
142 | } | |
143 | ||
144 | static const struct file_operations iio_event_chrdev_fileops = { | |
145 | .read = iio_event_chrdev_read, | |
146 | .poll = iio_event_poll, | |
147 | .release = iio_event_chrdev_release, | |
148 | .owner = THIS_MODULE, | |
149 | .llseek = noop_llseek, | |
150 | }; | |
151 | ||
152 | int iio_event_getfd(struct iio_dev *indio_dev) | |
153 | { | |
154 | struct iio_event_interface *ev_int = indio_dev->event_interface; | |
155 | int fd; | |
156 | ||
157 | if (ev_int == NULL) | |
158 | return -ENODEV; | |
159 | ||
160 | spin_lock_irq(&ev_int->wait.lock); | |
161 | if (__test_and_set_bit(IIO_BUSY_BIT_POS, &ev_int->flags)) { | |
162 | spin_unlock_irq(&ev_int->wait.lock); | |
163 | return -EBUSY; | |
164 | } | |
165 | spin_unlock_irq(&ev_int->wait.lock); | |
166 | iio_device_get(indio_dev); | |
167 | ||
168 | fd = anon_inode_getfd("iio:event", &iio_event_chrdev_fileops, | |
169 | indio_dev, O_RDONLY); | |
170 | if (fd < 0) { | |
171 | spin_lock_irq(&ev_int->wait.lock); | |
172 | __clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags); | |
173 | spin_unlock_irq(&ev_int->wait.lock); | |
174 | iio_device_put(indio_dev); | |
175 | } | |
176 | return fd; | |
177 | } | |
178 | ||
179 | static const char * const iio_ev_type_text[] = { | |
180 | [IIO_EV_TYPE_THRESH] = "thresh", | |
181 | [IIO_EV_TYPE_MAG] = "mag", | |
182 | [IIO_EV_TYPE_ROC] = "roc", | |
183 | [IIO_EV_TYPE_THRESH_ADAPTIVE] = "thresh_adaptive", | |
184 | [IIO_EV_TYPE_MAG_ADAPTIVE] = "mag_adaptive", | |
185 | }; | |
186 | ||
187 | static const char * const iio_ev_dir_text[] = { | |
188 | [IIO_EV_DIR_EITHER] = "either", | |
189 | [IIO_EV_DIR_RISING] = "rising", | |
190 | [IIO_EV_DIR_FALLING] = "falling" | |
191 | }; | |
192 | ||
193 | static ssize_t iio_ev_state_store(struct device *dev, | |
194 | struct device_attribute *attr, | |
195 | const char *buf, | |
196 | size_t len) | |
197 | { | |
198 | struct iio_dev *indio_dev = dev_to_iio_dev(dev); | |
199 | struct iio_dev_attr *this_attr = to_iio_dev_attr(attr); | |
200 | int ret; | |
201 | bool val; | |
202 | ||
203 | ret = strtobool(buf, &val); | |
204 | if (ret < 0) | |
205 | return ret; | |
206 | ||
207 | ret = indio_dev->info->write_event_config(indio_dev, | |
208 | this_attr->address, | |
209 | val); | |
210 | return (ret < 0) ? ret : len; | |
211 | } | |
212 | ||
213 | static ssize_t iio_ev_state_show(struct device *dev, | |
214 | struct device_attribute *attr, | |
215 | char *buf) | |
216 | { | |
217 | struct iio_dev *indio_dev = dev_to_iio_dev(dev); | |
218 | struct iio_dev_attr *this_attr = to_iio_dev_attr(attr); | |
219 | int val = indio_dev->info->read_event_config(indio_dev, | |
220 | this_attr->address); | |
221 | ||
222 | if (val < 0) | |
223 | return val; | |
224 | else | |
225 | return sprintf(buf, "%d\n", val); | |
226 | } | |
227 | ||
228 | static ssize_t iio_ev_value_show(struct device *dev, | |
229 | struct device_attribute *attr, | |
230 | char *buf) | |
231 | { | |
232 | struct iio_dev *indio_dev = dev_to_iio_dev(dev); | |
233 | struct iio_dev_attr *this_attr = to_iio_dev_attr(attr); | |
234 | int val, ret; | |
235 | ||
236 | ret = indio_dev->info->read_event_value(indio_dev, | |
237 | this_attr->address, &val); | |
238 | if (ret < 0) | |
239 | return ret; | |
240 | ||
241 | return sprintf(buf, "%d\n", val); | |
242 | } | |
243 | ||
244 | static ssize_t iio_ev_value_store(struct device *dev, | |
245 | struct device_attribute *attr, | |
246 | const char *buf, | |
247 | size_t len) | |
248 | { | |
249 | struct iio_dev *indio_dev = dev_to_iio_dev(dev); | |
250 | struct iio_dev_attr *this_attr = to_iio_dev_attr(attr); | |
251 | int val; | |
252 | int ret; | |
253 | ||
254 | if (!indio_dev->info->write_event_value) | |
255 | return -EINVAL; | |
256 | ||
257 | ret = kstrtoint(buf, 10, &val); | |
258 | if (ret) | |
259 | return ret; | |
260 | ||
261 | ret = indio_dev->info->write_event_value(indio_dev, this_attr->address, | |
262 | val); | |
263 | if (ret < 0) | |
264 | return ret; | |
265 | ||
266 | return len; | |
267 | } | |
268 | ||
269 | static int iio_device_add_event_sysfs(struct iio_dev *indio_dev, | |
270 | struct iio_chan_spec const *chan) | |
271 | { | |
272 | int ret = 0, i, attrcount = 0; | |
273 | u64 mask = 0; | |
274 | char *postfix; | |
275 | if (!chan->event_mask) | |
276 | return 0; | |
277 | ||
278 | for_each_set_bit(i, &chan->event_mask, sizeof(chan->event_mask)*8) { | |
279 | postfix = kasprintf(GFP_KERNEL, "%s_%s_en", | |
280 | iio_ev_type_text[i/IIO_EV_DIR_MAX], | |
281 | iio_ev_dir_text[i%IIO_EV_DIR_MAX]); | |
282 | if (postfix == NULL) { | |
283 | ret = -ENOMEM; | |
284 | goto error_ret; | |
285 | } | |
286 | if (chan->modified) | |
287 | mask = IIO_MOD_EVENT_CODE(chan->type, 0, chan->channel2, | |
288 | i/IIO_EV_DIR_MAX, | |
289 | i%IIO_EV_DIR_MAX); | |
290 | else if (chan->differential) | |
291 | mask = IIO_EVENT_CODE(chan->type, | |
292 | 0, 0, | |
293 | i%IIO_EV_DIR_MAX, | |
294 | i/IIO_EV_DIR_MAX, | |
295 | 0, | |
296 | chan->channel, | |
297 | chan->channel2); | |
298 | else | |
299 | mask = IIO_UNMOD_EVENT_CODE(chan->type, | |
300 | chan->channel, | |
301 | i/IIO_EV_DIR_MAX, | |
302 | i%IIO_EV_DIR_MAX); | |
303 | ||
304 | ret = __iio_add_chan_devattr(postfix, | |
305 | chan, | |
306 | &iio_ev_state_show, | |
307 | iio_ev_state_store, | |
308 | mask, | |
309 | 0, | |
310 | &indio_dev->dev, | |
311 | &indio_dev->event_interface-> | |
312 | dev_attr_list); | |
313 | kfree(postfix); | |
314 | if (ret) | |
315 | goto error_ret; | |
316 | attrcount++; | |
317 | postfix = kasprintf(GFP_KERNEL, "%s_%s_value", | |
318 | iio_ev_type_text[i/IIO_EV_DIR_MAX], | |
319 | iio_ev_dir_text[i%IIO_EV_DIR_MAX]); | |
320 | if (postfix == NULL) { | |
321 | ret = -ENOMEM; | |
322 | goto error_ret; | |
323 | } | |
324 | ret = __iio_add_chan_devattr(postfix, chan, | |
325 | iio_ev_value_show, | |
326 | iio_ev_value_store, | |
327 | mask, | |
328 | 0, | |
329 | &indio_dev->dev, | |
330 | &indio_dev->event_interface-> | |
331 | dev_attr_list); | |
332 | kfree(postfix); | |
333 | if (ret) | |
334 | goto error_ret; | |
335 | attrcount++; | |
336 | } | |
337 | ret = attrcount; | |
338 | error_ret: | |
339 | return ret; | |
340 | } | |
341 | ||
342 | static inline void __iio_remove_event_config_attrs(struct iio_dev *indio_dev) | |
343 | { | |
344 | struct iio_dev_attr *p, *n; | |
345 | list_for_each_entry_safe(p, n, | |
346 | &indio_dev->event_interface-> | |
347 | dev_attr_list, l) { | |
348 | kfree(p->dev_attr.attr.name); | |
349 | kfree(p); | |
350 | } | |
351 | } | |
352 | ||
353 | static inline int __iio_add_event_config_attrs(struct iio_dev *indio_dev) | |
354 | { | |
355 | int j, ret, attrcount = 0; | |
356 | ||
357 | /* Dynically created from the channels array */ | |
358 | for (j = 0; j < indio_dev->num_channels; j++) { | |
359 | ret = iio_device_add_event_sysfs(indio_dev, | |
360 | &indio_dev->channels[j]); | |
361 | if (ret < 0) | |
362 | return ret; | |
363 | attrcount += ret; | |
364 | } | |
365 | return attrcount; | |
366 | } | |
367 | ||
368 | static bool iio_check_for_dynamic_events(struct iio_dev *indio_dev) | |
369 | { | |
370 | int j; | |
371 | ||
372 | for (j = 0; j < indio_dev->num_channels; j++) | |
373 | if (indio_dev->channels[j].event_mask != 0) | |
374 | return true; | |
375 | return false; | |
376 | } | |
377 | ||
378 | static void iio_setup_ev_int(struct iio_event_interface *ev_int) | |
379 | { | |
380 | INIT_KFIFO(ev_int->det_events); | |
381 | init_waitqueue_head(&ev_int->wait); | |
382 | } | |
383 | ||
384 | static const char *iio_event_group_name = "events"; | |
385 | int iio_device_register_eventset(struct iio_dev *indio_dev) | |
386 | { | |
387 | struct iio_dev_attr *p; | |
388 | int ret = 0, attrcount_orig = 0, attrcount, attrn; | |
389 | struct attribute **attr; | |
390 | ||
391 | if (!(indio_dev->info->event_attrs || | |
392 | iio_check_for_dynamic_events(indio_dev))) | |
393 | return 0; | |
394 | ||
395 | indio_dev->event_interface = | |
396 | kzalloc(sizeof(struct iio_event_interface), GFP_KERNEL); | |
397 | if (indio_dev->event_interface == NULL) { | |
398 | ret = -ENOMEM; | |
399 | goto error_ret; | |
400 | } | |
401 | ||
402 | INIT_LIST_HEAD(&indio_dev->event_interface->dev_attr_list); | |
403 | ||
404 | iio_setup_ev_int(indio_dev->event_interface); | |
405 | if (indio_dev->info->event_attrs != NULL) { | |
406 | attr = indio_dev->info->event_attrs->attrs; | |
407 | while (*attr++ != NULL) | |
408 | attrcount_orig++; | |
409 | } | |
410 | attrcount = attrcount_orig; | |
411 | if (indio_dev->channels) { | |
412 | ret = __iio_add_event_config_attrs(indio_dev); | |
413 | if (ret < 0) | |
414 | goto error_free_setup_event_lines; | |
415 | attrcount += ret; | |
416 | } | |
417 | ||
418 | indio_dev->event_interface->group.name = iio_event_group_name; | |
419 | indio_dev->event_interface->group.attrs = kcalloc(attrcount + 1, | |
420 | sizeof(indio_dev->event_interface->group.attrs[0]), | |
421 | GFP_KERNEL); | |
422 | if (indio_dev->event_interface->group.attrs == NULL) { | |
423 | ret = -ENOMEM; | |
424 | goto error_free_setup_event_lines; | |
425 | } | |
426 | if (indio_dev->info->event_attrs) | |
427 | memcpy(indio_dev->event_interface->group.attrs, | |
428 | indio_dev->info->event_attrs->attrs, | |
429 | sizeof(indio_dev->event_interface->group.attrs[0]) | |
430 | *attrcount_orig); | |
431 | attrn = attrcount_orig; | |
432 | /* Add all elements from the list. */ | |
433 | list_for_each_entry(p, | |
434 | &indio_dev->event_interface->dev_attr_list, | |
435 | l) | |
436 | indio_dev->event_interface->group.attrs[attrn++] = | |
437 | &p->dev_attr.attr; | |
438 | indio_dev->groups[indio_dev->groupcounter++] = | |
439 | &indio_dev->event_interface->group; | |
440 | ||
441 | return 0; | |
442 | ||
443 | error_free_setup_event_lines: | |
444 | __iio_remove_event_config_attrs(indio_dev); | |
445 | kfree(indio_dev->event_interface); | |
446 | error_ret: | |
447 | ||
448 | return ret; | |
449 | } | |
450 | ||
451 | void iio_device_unregister_eventset(struct iio_dev *indio_dev) | |
452 | { | |
453 | if (indio_dev->event_interface == NULL) | |
454 | return; | |
455 | __iio_remove_event_config_attrs(indio_dev); | |
456 | kfree(indio_dev->event_interface->group.attrs); | |
457 | kfree(indio_dev->event_interface); | |
458 | } |