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1637db44 JC |
1 | /* The industrial I/O core, trigger handling functions |
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 | ||
10 | #include <linux/kernel.h> | |
11 | #include <linux/module.h> | |
12 | #include <linux/idr.h> | |
13 | #include <linux/err.h> | |
14 | #include <linux/device.h> | |
15 | #include <linux/interrupt.h> | |
16 | #include <linux/list.h> | |
5a0e3ad6 | 17 | #include <linux/slab.h> |
1637db44 JC |
18 | |
19 | #include "iio.h" | |
20 | #include "trigger.h" | |
21 | ||
22 | /* RFC - Question of approach | |
23 | * Make the common case (single sensor single trigger) | |
24 | * simple by starting trigger capture from when first sensors | |
25 | * is added. | |
26 | * | |
27 | * Complex simultaneous start requires use of 'hold' functionality | |
28 | * of the trigger. (not implemented) | |
29 | * | |
30 | * Any other suggestions? | |
31 | */ | |
32 | ||
33 | ||
34 | static DEFINE_IDR(iio_trigger_idr); | |
35 | static DEFINE_SPINLOCK(iio_trigger_idr_lock); | |
36 | ||
37 | /* Single list of all available triggers */ | |
38 | static LIST_HEAD(iio_trigger_list); | |
39 | static DEFINE_MUTEX(iio_trigger_list_lock); | |
40 | ||
41 | /** | |
42 | * iio_trigger_register_sysfs() - create a device for this trigger | |
43 | * @trig_info: the trigger | |
44 | * | |
45 | * Also adds any control attribute registered by the trigger driver | |
46 | **/ | |
47 | static int iio_trigger_register_sysfs(struct iio_trigger *trig_info) | |
48 | { | |
49 | int ret = 0; | |
50 | ||
51 | if (trig_info->control_attrs) | |
52 | ret = sysfs_create_group(&trig_info->dev.kobj, | |
53 | trig_info->control_attrs); | |
54 | ||
55 | return ret; | |
56 | } | |
57 | ||
58 | static void iio_trigger_unregister_sysfs(struct iio_trigger *trig_info) | |
59 | { | |
60 | if (trig_info->control_attrs) | |
61 | sysfs_remove_group(&trig_info->dev.kobj, | |
62 | trig_info->control_attrs); | |
63 | } | |
64 | ||
65 | ||
66 | /** | |
67 | * iio_trigger_register_id() - get a unique id for this trigger | |
68 | * @trig_info: the trigger | |
69 | **/ | |
70 | static int iio_trigger_register_id(struct iio_trigger *trig_info) | |
71 | { | |
72 | int ret = 0; | |
73 | ||
74 | idr_again: | |
75 | if (unlikely(idr_pre_get(&iio_trigger_idr, GFP_KERNEL) == 0)) | |
76 | return -ENOMEM; | |
77 | ||
78 | spin_lock(&iio_trigger_idr_lock); | |
79 | ret = idr_get_new(&iio_trigger_idr, NULL, &trig_info->id); | |
80 | spin_unlock(&iio_trigger_idr_lock); | |
81 | if (unlikely(ret == -EAGAIN)) | |
82 | goto idr_again; | |
83 | else if (likely(!ret)) | |
84 | trig_info->id = trig_info->id & MAX_ID_MASK; | |
85 | ||
86 | return ret; | |
87 | } | |
88 | ||
89 | /** | |
90 | * iio_trigger_unregister_id() - free up unique id for use by another trigger | |
91 | * @trig_info: the trigger | |
92 | **/ | |
93 | static void iio_trigger_unregister_id(struct iio_trigger *trig_info) | |
94 | { | |
95 | spin_lock(&iio_trigger_idr_lock); | |
96 | idr_remove(&iio_trigger_idr, trig_info->id); | |
97 | spin_unlock(&iio_trigger_idr_lock); | |
98 | } | |
99 | ||
100 | int iio_trigger_register(struct iio_trigger *trig_info) | |
101 | { | |
102 | int ret; | |
103 | ||
104 | ret = iio_trigger_register_id(trig_info); | |
105 | if (ret) | |
106 | goto error_ret; | |
107 | /* Set the name used for the sysfs directory etc */ | |
108 | dev_set_name(&trig_info->dev, "trigger%ld", | |
109 | (unsigned long) trig_info->id); | |
110 | ||
111 | ret = device_add(&trig_info->dev); | |
112 | if (ret) | |
113 | goto error_unregister_id; | |
114 | ||
115 | ret = iio_trigger_register_sysfs(trig_info); | |
116 | if (ret) | |
117 | goto error_device_del; | |
118 | ||
119 | /* Add to list of available triggers held by the IIO core */ | |
120 | mutex_lock(&iio_trigger_list_lock); | |
121 | list_add_tail(&trig_info->list, &iio_trigger_list); | |
122 | mutex_unlock(&iio_trigger_list_lock); | |
123 | ||
124 | return 0; | |
125 | ||
126 | error_device_del: | |
127 | device_del(&trig_info->dev); | |
128 | error_unregister_id: | |
129 | iio_trigger_unregister_id(trig_info); | |
130 | error_ret: | |
131 | return ret; | |
132 | } | |
133 | EXPORT_SYMBOL(iio_trigger_register); | |
134 | ||
135 | void iio_trigger_unregister(struct iio_trigger *trig_info) | |
136 | { | |
137 | struct iio_trigger *cursor; | |
138 | ||
139 | mutex_lock(&iio_trigger_list_lock); | |
140 | list_for_each_entry(cursor, &iio_trigger_list, list) | |
141 | if (cursor == trig_info) { | |
142 | list_del(&cursor->list); | |
143 | break; | |
144 | } | |
145 | mutex_unlock(&iio_trigger_list_lock); | |
146 | ||
147 | iio_trigger_unregister_sysfs(trig_info); | |
148 | iio_trigger_unregister_id(trig_info); | |
149 | /* Possible issue in here */ | |
150 | device_unregister(&trig_info->dev); | |
151 | } | |
152 | EXPORT_SYMBOL(iio_trigger_unregister); | |
153 | ||
154 | struct iio_trigger *iio_trigger_find_by_name(const char *name, size_t len) | |
155 | { | |
156 | struct iio_trigger *trig; | |
157 | bool found = false; | |
158 | ||
159 | mutex_lock(&iio_trigger_list_lock); | |
160 | list_for_each_entry(trig, &iio_trigger_list, list) { | |
161 | if (strncmp(trig->name, name, len) == 0) { | |
162 | found = true; | |
163 | break; | |
164 | } | |
165 | } | |
166 | mutex_unlock(&iio_trigger_list_lock); | |
167 | ||
168 | return found ? trig : NULL; | |
169 | }; | |
170 | EXPORT_SYMBOL(iio_trigger_find_by_name); | |
171 | ||
172 | void iio_trigger_poll(struct iio_trigger *trig) | |
173 | { | |
174 | struct iio_poll_func *pf_cursor; | |
175 | ||
176 | list_for_each_entry(pf_cursor, &trig->pollfunc_list, list) { | |
177 | if (pf_cursor->poll_func_immediate) { | |
178 | pf_cursor->poll_func_immediate(pf_cursor->private_data); | |
179 | trig->use_count++; | |
180 | } | |
181 | } | |
182 | list_for_each_entry(pf_cursor, &trig->pollfunc_list, list) { | |
183 | if (pf_cursor->poll_func_main) { | |
184 | pf_cursor->poll_func_main(pf_cursor->private_data); | |
185 | trig->use_count++; | |
186 | } | |
187 | } | |
188 | } | |
189 | EXPORT_SYMBOL(iio_trigger_poll); | |
190 | ||
191 | void iio_trigger_notify_done(struct iio_trigger *trig) | |
192 | { | |
193 | trig->use_count--; | |
194 | if (trig->use_count == 0 && trig->try_reenable) | |
195 | if (trig->try_reenable(trig)) { | |
196 | /* Missed and interrupt so launch new poll now */ | |
197 | trig->timestamp = 0; | |
198 | iio_trigger_poll(trig); | |
199 | } | |
200 | } | |
201 | EXPORT_SYMBOL(iio_trigger_notify_done); | |
202 | ||
203 | /** | |
204 | * iio_trigger_read_name() - retrieve useful identifying name | |
205 | **/ | |
206 | ssize_t iio_trigger_read_name(struct device *dev, | |
207 | struct device_attribute *attr, | |
208 | char *buf) | |
209 | { | |
210 | struct iio_trigger *trig = dev_get_drvdata(dev); | |
211 | return sprintf(buf, "%s\n", trig->name); | |
212 | } | |
213 | EXPORT_SYMBOL(iio_trigger_read_name); | |
214 | ||
215 | /* Trigger Consumer related functions */ | |
216 | ||
217 | /* Complexity in here. With certain triggers (datardy) an acknowledgement | |
218 | * may be needed if the pollfuncs do not include the data read for the | |
219 | * triggering device. | |
220 | * This is not currently handled. Alternative of not enabling trigger unless | |
221 | * the relevant function is in there may be the best option. | |
222 | */ | |
223 | /* Worth protecting against double additions?*/ | |
224 | int iio_trigger_attach_poll_func(struct iio_trigger *trig, | |
225 | struct iio_poll_func *pf) | |
226 | { | |
227 | int ret = 0; | |
228 | unsigned long flags; | |
229 | ||
230 | spin_lock_irqsave(&trig->pollfunc_list_lock, flags); | |
231 | list_add_tail(&pf->list, &trig->pollfunc_list); | |
232 | spin_unlock_irqrestore(&trig->pollfunc_list_lock, flags); | |
233 | ||
234 | if (trig->set_trigger_state) | |
235 | ret = trig->set_trigger_state(trig, true); | |
236 | if (ret) { | |
237 | printk(KERN_ERR "set trigger state failed\n"); | |
238 | list_del(&pf->list); | |
239 | } | |
240 | return ret; | |
241 | } | |
242 | EXPORT_SYMBOL(iio_trigger_attach_poll_func); | |
243 | ||
244 | int iio_trigger_dettach_poll_func(struct iio_trigger *trig, | |
245 | struct iio_poll_func *pf) | |
246 | { | |
247 | struct iio_poll_func *pf_cursor; | |
248 | unsigned long flags; | |
249 | int ret = -EINVAL; | |
250 | ||
251 | spin_lock_irqsave(&trig->pollfunc_list_lock, flags); | |
252 | list_for_each_entry(pf_cursor, &trig->pollfunc_list, list) | |
253 | if (pf_cursor == pf) { | |
254 | ret = 0; | |
255 | break; | |
256 | } | |
257 | if (!ret) { | |
258 | if (list_is_singular(&trig->pollfunc_list) | |
259 | && trig->set_trigger_state) { | |
260 | spin_unlock_irqrestore(&trig->pollfunc_list_lock, | |
261 | flags); | |
262 | /* May sleep hence cannot hold the spin lock */ | |
263 | ret = trig->set_trigger_state(trig, false); | |
264 | if (ret) | |
265 | goto error_ret; | |
266 | spin_lock_irqsave(&trig->pollfunc_list_lock, flags); | |
267 | } | |
268 | /* | |
269 | * Now we can delete safe in the knowledge that, if this is | |
270 | * the last pollfunc then we have disabled the trigger anyway | |
271 | * and so nothing should be able to call the pollfunc. | |
272 | */ | |
273 | list_del(&pf_cursor->list); | |
274 | } | |
275 | spin_unlock_irqrestore(&trig->pollfunc_list_lock, flags); | |
276 | ||
277 | error_ret: | |
278 | return ret; | |
279 | } | |
280 | EXPORT_SYMBOL(iio_trigger_dettach_poll_func); | |
281 | ||
282 | /** | |
283 | * iio_trigger_read_currrent() trigger consumer sysfs query which trigger | |
284 | * | |
285 | * For trigger consumers the current_trigger interface allows the trigger | |
286 | * used by the device to be queried. | |
287 | **/ | |
288 | static ssize_t iio_trigger_read_current(struct device *dev, | |
289 | struct device_attribute *attr, | |
290 | char *buf) | |
291 | { | |
292 | struct iio_dev *dev_info = dev_get_drvdata(dev); | |
293 | int len = 0; | |
294 | if (dev_info->trig) | |
295 | len = snprintf(buf, | |
296 | IIO_TRIGGER_NAME_LENGTH, | |
297 | "%s\n", | |
298 | dev_info->trig->name); | |
299 | return len; | |
300 | } | |
301 | ||
302 | /** | |
303 | * iio_trigger_write_current() trigger consumer sysfs set current trigger | |
304 | * | |
305 | * For trigger consumers the current_trigger interface allows the trigger | |
306 | * used for this device to be specified at run time based on the triggers | |
307 | * name. | |
308 | **/ | |
309 | static ssize_t iio_trigger_write_current(struct device *dev, | |
310 | struct device_attribute *attr, | |
311 | const char *buf, | |
312 | size_t len) | |
313 | { | |
314 | struct iio_dev *dev_info = dev_get_drvdata(dev); | |
315 | struct iio_trigger *oldtrig = dev_info->trig; | |
316 | mutex_lock(&dev_info->mlock); | |
317 | if (dev_info->currentmode == INDIO_RING_TRIGGERED) { | |
318 | mutex_unlock(&dev_info->mlock); | |
319 | return -EBUSY; | |
320 | } | |
321 | mutex_unlock(&dev_info->mlock); | |
322 | ||
323 | len = len < IIO_TRIGGER_NAME_LENGTH ? len : IIO_TRIGGER_NAME_LENGTH; | |
324 | ||
325 | dev_info->trig = iio_trigger_find_by_name(buf, len); | |
326 | if (oldtrig && dev_info->trig != oldtrig) | |
327 | iio_put_trigger(oldtrig); | |
328 | if (dev_info->trig) | |
329 | iio_get_trigger(dev_info->trig); | |
330 | ||
331 | return len; | |
332 | } | |
333 | ||
334 | DEVICE_ATTR(current_trigger, S_IRUGO | S_IWUSR, | |
335 | iio_trigger_read_current, | |
336 | iio_trigger_write_current); | |
337 | ||
338 | static struct attribute *iio_trigger_consumer_attrs[] = { | |
339 | &dev_attr_current_trigger.attr, | |
340 | NULL, | |
341 | }; | |
342 | ||
343 | static const struct attribute_group iio_trigger_consumer_attr_group = { | |
344 | .name = "trigger", | |
345 | .attrs = iio_trigger_consumer_attrs, | |
346 | }; | |
347 | ||
348 | static void iio_trig_release(struct device *device) | |
349 | { | |
350 | struct iio_trigger *trig = to_iio_trigger(device); | |
351 | kfree(trig); | |
352 | iio_put(); | |
353 | } | |
354 | ||
355 | static struct device_type iio_trig_type = { | |
356 | .release = iio_trig_release, | |
357 | }; | |
358 | ||
359 | struct iio_trigger *iio_allocate_trigger(void) | |
360 | { | |
361 | struct iio_trigger *trig; | |
362 | trig = kzalloc(sizeof *trig, GFP_KERNEL); | |
363 | if (trig) { | |
364 | trig->dev.type = &iio_trig_type; | |
365 | trig->dev.class = &iio_class; | |
366 | device_initialize(&trig->dev); | |
367 | dev_set_drvdata(&trig->dev, (void *)trig); | |
368 | spin_lock_init(&trig->pollfunc_list_lock); | |
369 | INIT_LIST_HEAD(&trig->list); | |
370 | INIT_LIST_HEAD(&trig->pollfunc_list); | |
371 | iio_get(); | |
372 | } | |
373 | return trig; | |
374 | } | |
375 | EXPORT_SYMBOL(iio_allocate_trigger); | |
376 | ||
377 | void iio_free_trigger(struct iio_trigger *trig) | |
378 | { | |
379 | if (trig) | |
380 | put_device(&trig->dev); | |
381 | } | |
382 | EXPORT_SYMBOL(iio_free_trigger); | |
383 | ||
384 | int iio_device_register_trigger_consumer(struct iio_dev *dev_info) | |
385 | { | |
386 | int ret; | |
387 | ret = sysfs_create_group(&dev_info->dev.kobj, | |
388 | &iio_trigger_consumer_attr_group); | |
389 | return ret; | |
390 | } | |
391 | EXPORT_SYMBOL(iio_device_register_trigger_consumer); | |
392 | ||
393 | int iio_device_unregister_trigger_consumer(struct iio_dev *dev_info) | |
394 | { | |
395 | sysfs_remove_group(&dev_info->dev.kobj, | |
396 | &iio_trigger_consumer_attr_group); | |
397 | return 0; | |
398 | } | |
399 | EXPORT_SYMBOL(iio_device_unregister_trigger_consumer); | |
400 |