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