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/idr.h> 12 #include <linux/err.h> 13 #include <linux/device.h> 14 #include <linux/interrupt.h> 15 #include <linux/list.h> 16 #include <linux/slab.h> 17 18 #include <linux/iio/iio.h> 19 #include <linux/iio/trigger.h> 20 #include "iio_core.h" 21 #include "iio_core_trigger.h" 22 #include <linux/iio/trigger_consumer.h> 23 24 /* RFC - Question of approach 25 * Make the common case (single sensor single trigger) 26 * simple by starting trigger capture from when first sensors 27 * is added. 28 * 29 * Complex simultaneous start requires use of 'hold' functionality 30 * of the trigger. (not implemented) 31 * 32 * Any other suggestions? 33 */ 34 35 static DEFINE_IDA(iio_trigger_ida); 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_read_name() - retrieve useful identifying name 43 **/ 44 static ssize_t iio_trigger_read_name(struct device *dev, 45 struct device_attribute *attr, 46 char *buf) 47 { 48 struct iio_trigger *trig = dev_get_drvdata(dev); 49 return sprintf(buf, "%s\n", trig->name); 50 } 51 52 static DEVICE_ATTR(name, S_IRUGO, iio_trigger_read_name, NULL); 53 54 /** 55 * iio_trigger_register_sysfs() - create a device for this trigger 56 * @trig_info: the trigger 57 * 58 * Also adds any control attribute registered by the trigger driver 59 **/ 60 static int iio_trigger_register_sysfs(struct iio_trigger *trig_info) 61 { 62 return sysfs_add_file_to_group(&trig_info->dev.kobj, 63 &dev_attr_name.attr, 64 NULL); 65 } 66 67 static void iio_trigger_unregister_sysfs(struct iio_trigger *trig_info) 68 { 69 sysfs_remove_file_from_group(&trig_info->dev.kobj, 70 &dev_attr_name.attr, 71 NULL); 72 } 73 74 int iio_trigger_register(struct iio_trigger *trig_info) 75 { 76 int ret; 77 78 trig_info->id = ida_simple_get(&iio_trigger_ida, 0, 0, GFP_KERNEL); 79 if (trig_info->id < 0) { 80 ret = trig_info->id; 81 goto error_ret; 82 } 83 /* Set the name used for the sysfs directory etc */ 84 dev_set_name(&trig_info->dev, "trigger%ld", 85 (unsigned long) trig_info->id); 86 87 ret = device_add(&trig_info->dev); 88 if (ret) 89 goto error_unregister_id; 90 91 ret = iio_trigger_register_sysfs(trig_info); 92 if (ret) 93 goto error_device_del; 94 95 /* Add to list of available triggers held by the IIO core */ 96 mutex_lock(&iio_trigger_list_lock); 97 list_add_tail(&trig_info->list, &iio_trigger_list); 98 mutex_unlock(&iio_trigger_list_lock); 99 100 return 0; 101 102 error_device_del: 103 device_del(&trig_info->dev); 104 error_unregister_id: 105 ida_simple_remove(&iio_trigger_ida, trig_info->id); 106 error_ret: 107 return ret; 108 } 109 EXPORT_SYMBOL(iio_trigger_register); 110 111 void iio_trigger_unregister(struct iio_trigger *trig_info) 112 { 113 mutex_lock(&iio_trigger_list_lock); 114 list_del(&trig_info->list); 115 mutex_unlock(&iio_trigger_list_lock); 116 117 iio_trigger_unregister_sysfs(trig_info); 118 ida_simple_remove(&iio_trigger_ida, trig_info->id); 119 /* Possible issue in here */ 120 device_unregister(&trig_info->dev); 121 } 122 EXPORT_SYMBOL(iio_trigger_unregister); 123 124 static struct iio_trigger *iio_trigger_find_by_name(const char *name, 125 size_t len) 126 { 127 struct iio_trigger *trig = NULL, *iter; 128 129 mutex_lock(&iio_trigger_list_lock); 130 list_for_each_entry(iter, &iio_trigger_list, list) 131 if (sysfs_streq(iter->name, name)) { 132 trig = iter; 133 break; 134 } 135 mutex_unlock(&iio_trigger_list_lock); 136 137 return trig; 138 } 139 140 void iio_trigger_poll(struct iio_trigger *trig, s64 time) 141 { 142 int i; 143 if (!trig->use_count) 144 for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) 145 if (trig->subirqs[i].enabled) { 146 trig->use_count++; 147 generic_handle_irq(trig->subirq_base + i); 148 } 149 } 150 EXPORT_SYMBOL(iio_trigger_poll); 151 152 irqreturn_t iio_trigger_generic_data_rdy_poll(int irq, void *private) 153 { 154 iio_trigger_poll(private, iio_get_time_ns()); 155 return IRQ_HANDLED; 156 } 157 EXPORT_SYMBOL(iio_trigger_generic_data_rdy_poll); 158 159 void iio_trigger_poll_chained(struct iio_trigger *trig, s64 time) 160 { 161 int i; 162 if (!trig->use_count) 163 for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) 164 if (trig->subirqs[i].enabled) { 165 trig->use_count++; 166 handle_nested_irq(trig->subirq_base + i); 167 } 168 } 169 EXPORT_SYMBOL(iio_trigger_poll_chained); 170 171 void iio_trigger_notify_done(struct iio_trigger *trig) 172 { 173 trig->use_count--; 174 if (trig->use_count == 0 && trig->ops && trig->ops->try_reenable) 175 if (trig->ops->try_reenable(trig)) 176 /* Missed and interrupt so launch new poll now */ 177 iio_trigger_poll(trig, 0); 178 } 179 EXPORT_SYMBOL(iio_trigger_notify_done); 180 181 /* Trigger Consumer related functions */ 182 static int iio_trigger_get_irq(struct iio_trigger *trig) 183 { 184 int ret; 185 mutex_lock(&trig->pool_lock); 186 ret = bitmap_find_free_region(trig->pool, 187 CONFIG_IIO_CONSUMERS_PER_TRIGGER, 188 ilog2(1)); 189 mutex_unlock(&trig->pool_lock); 190 if (ret >= 0) 191 ret += trig->subirq_base; 192 193 return ret; 194 } 195 196 static void iio_trigger_put_irq(struct iio_trigger *trig, int irq) 197 { 198 mutex_lock(&trig->pool_lock); 199 clear_bit(irq - trig->subirq_base, trig->pool); 200 mutex_unlock(&trig->pool_lock); 201 } 202 203 /* Complexity in here. With certain triggers (datardy) an acknowledgement 204 * may be needed if the pollfuncs do not include the data read for the 205 * triggering device. 206 * This is not currently handled. Alternative of not enabling trigger unless 207 * the relevant function is in there may be the best option. 208 */ 209 /* Worth protecting against double additions?*/ 210 static int iio_trigger_attach_poll_func(struct iio_trigger *trig, 211 struct iio_poll_func *pf) 212 { 213 int ret = 0; 214 bool notinuse 215 = bitmap_empty(trig->pool, CONFIG_IIO_CONSUMERS_PER_TRIGGER); 216 217 /* Prevent the module being removed whilst attached to a trigger */ 218 __module_get(pf->indio_dev->info->driver_module); 219 pf->irq = iio_trigger_get_irq(trig); 220 ret = request_threaded_irq(pf->irq, pf->h, pf->thread, 221 pf->type, pf->name, 222 pf); 223 if (ret < 0) { 224 module_put(pf->indio_dev->info->driver_module); 225 return ret; 226 } 227 228 if (trig->ops && trig->ops->set_trigger_state && notinuse) { 229 ret = trig->ops->set_trigger_state(trig, true); 230 if (ret < 0) 231 module_put(pf->indio_dev->info->driver_module); 232 } 233 234 return ret; 235 } 236 237 static int iio_trigger_dettach_poll_func(struct iio_trigger *trig, 238 struct iio_poll_func *pf) 239 { 240 int ret = 0; 241 bool no_other_users 242 = (bitmap_weight(trig->pool, 243 CONFIG_IIO_CONSUMERS_PER_TRIGGER) 244 == 1); 245 if (trig->ops && trig->ops->set_trigger_state && no_other_users) { 246 ret = trig->ops->set_trigger_state(trig, false); 247 if (ret) 248 goto error_ret; 249 } 250 iio_trigger_put_irq(trig, pf->irq); 251 free_irq(pf->irq, pf); 252 module_put(pf->indio_dev->info->driver_module); 253 254 error_ret: 255 return ret; 256 } 257 258 irqreturn_t iio_pollfunc_store_time(int irq, void *p) 259 { 260 struct iio_poll_func *pf = p; 261 pf->timestamp = iio_get_time_ns(); 262 return IRQ_WAKE_THREAD; 263 } 264 EXPORT_SYMBOL(iio_pollfunc_store_time); 265 266 struct iio_poll_func 267 *iio_alloc_pollfunc(irqreturn_t (*h)(int irq, void *p), 268 irqreturn_t (*thread)(int irq, void *p), 269 int type, 270 struct iio_dev *indio_dev, 271 const char *fmt, 272 ...) 273 { 274 va_list vargs; 275 struct iio_poll_func *pf; 276 277 pf = kmalloc(sizeof *pf, GFP_KERNEL); 278 if (pf == NULL) 279 return NULL; 280 va_start(vargs, fmt); 281 pf->name = kvasprintf(GFP_KERNEL, fmt, vargs); 282 va_end(vargs); 283 if (pf->name == NULL) { 284 kfree(pf); 285 return NULL; 286 } 287 pf->h = h; 288 pf->thread = thread; 289 pf->type = type; 290 pf->indio_dev = indio_dev; 291 292 return pf; 293 } 294 EXPORT_SYMBOL_GPL(iio_alloc_pollfunc); 295 296 void iio_dealloc_pollfunc(struct iio_poll_func *pf) 297 { 298 kfree(pf->name); 299 kfree(pf); 300 } 301 EXPORT_SYMBOL_GPL(iio_dealloc_pollfunc); 302 303 /** 304 * iio_trigger_read_current() - trigger consumer sysfs query which trigger 305 * 306 * For trigger consumers the current_trigger interface allows the trigger 307 * used by the device to be queried. 308 **/ 309 static ssize_t iio_trigger_read_current(struct device *dev, 310 struct device_attribute *attr, 311 char *buf) 312 { 313 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 314 315 if (indio_dev->trig) 316 return sprintf(buf, "%s\n", indio_dev->trig->name); 317 return 0; 318 } 319 320 /** 321 * iio_trigger_write_current() trigger consumer sysfs set current trigger 322 * 323 * For trigger consumers the current_trigger interface allows the trigger 324 * used for this device to be specified at run time based on the triggers 325 * name. 326 **/ 327 static ssize_t iio_trigger_write_current(struct device *dev, 328 struct device_attribute *attr, 329 const char *buf, 330 size_t len) 331 { 332 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 333 struct iio_trigger *oldtrig = indio_dev->trig; 334 struct iio_trigger *trig; 335 int ret; 336 337 mutex_lock(&indio_dev->mlock); 338 if (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED) { 339 mutex_unlock(&indio_dev->mlock); 340 return -EBUSY; 341 } 342 mutex_unlock(&indio_dev->mlock); 343 344 trig = iio_trigger_find_by_name(buf, len); 345 if (oldtrig == trig) 346 return len; 347 348 if (trig && indio_dev->info->validate_trigger) { 349 ret = indio_dev->info->validate_trigger(indio_dev, trig); 350 if (ret) 351 return ret; 352 } 353 354 if (trig && trig->ops && trig->ops->validate_device) { 355 ret = trig->ops->validate_device(trig, indio_dev); 356 if (ret) 357 return ret; 358 } 359 360 indio_dev->trig = trig; 361 362 if (oldtrig && indio_dev->trig != oldtrig) 363 iio_trigger_put(oldtrig); 364 if (indio_dev->trig) 365 iio_trigger_get(indio_dev->trig); 366 367 return len; 368 } 369 370 static DEVICE_ATTR(current_trigger, S_IRUGO | S_IWUSR, 371 iio_trigger_read_current, 372 iio_trigger_write_current); 373 374 static struct attribute *iio_trigger_consumer_attrs[] = { 375 &dev_attr_current_trigger.attr, 376 NULL, 377 }; 378 379 static const struct attribute_group iio_trigger_consumer_attr_group = { 380 .name = "trigger", 381 .attrs = iio_trigger_consumer_attrs, 382 }; 383 384 static void iio_trig_release(struct device *device) 385 { 386 struct iio_trigger *trig = to_iio_trigger(device); 387 int i; 388 389 if (trig->subirq_base) { 390 for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) { 391 irq_modify_status(trig->subirq_base + i, 392 IRQ_NOAUTOEN, 393 IRQ_NOREQUEST | IRQ_NOPROBE); 394 irq_set_chip(trig->subirq_base + i, 395 NULL); 396 irq_set_handler(trig->subirq_base + i, 397 NULL); 398 } 399 400 irq_free_descs(trig->subirq_base, 401 CONFIG_IIO_CONSUMERS_PER_TRIGGER); 402 } 403 kfree(trig->name); 404 kfree(trig); 405 } 406 407 static struct device_type iio_trig_type = { 408 .release = iio_trig_release, 409 }; 410 411 static void iio_trig_subirqmask(struct irq_data *d) 412 { 413 struct irq_chip *chip = irq_data_get_irq_chip(d); 414 struct iio_trigger *trig 415 = container_of(chip, 416 struct iio_trigger, subirq_chip); 417 trig->subirqs[d->irq - trig->subirq_base].enabled = false; 418 } 419 420 static void iio_trig_subirqunmask(struct irq_data *d) 421 { 422 struct irq_chip *chip = irq_data_get_irq_chip(d); 423 struct iio_trigger *trig 424 = container_of(chip, 425 struct iio_trigger, subirq_chip); 426 trig->subirqs[d->irq - trig->subirq_base].enabled = true; 427 } 428 429 struct iio_trigger *iio_trigger_alloc(const char *fmt, ...) 430 { 431 va_list vargs; 432 struct iio_trigger *trig; 433 trig = kzalloc(sizeof *trig, GFP_KERNEL); 434 if (trig) { 435 int i; 436 trig->dev.type = &iio_trig_type; 437 trig->dev.bus = &iio_bus_type; 438 device_initialize(&trig->dev); 439 dev_set_drvdata(&trig->dev, (void *)trig); 440 441 mutex_init(&trig->pool_lock); 442 trig->subirq_base 443 = irq_alloc_descs(-1, 0, 444 CONFIG_IIO_CONSUMERS_PER_TRIGGER, 445 0); 446 if (trig->subirq_base < 0) { 447 kfree(trig); 448 return NULL; 449 } 450 va_start(vargs, fmt); 451 trig->name = kvasprintf(GFP_KERNEL, fmt, vargs); 452 va_end(vargs); 453 if (trig->name == NULL) { 454 irq_free_descs(trig->subirq_base, 455 CONFIG_IIO_CONSUMERS_PER_TRIGGER); 456 kfree(trig); 457 return NULL; 458 } 459 trig->subirq_chip.name = trig->name; 460 trig->subirq_chip.irq_mask = &iio_trig_subirqmask; 461 trig->subirq_chip.irq_unmask = &iio_trig_subirqunmask; 462 for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) { 463 irq_set_chip(trig->subirq_base + i, 464 &trig->subirq_chip); 465 irq_set_handler(trig->subirq_base + i, 466 &handle_simple_irq); 467 irq_modify_status(trig->subirq_base + i, 468 IRQ_NOREQUEST | IRQ_NOAUTOEN, 469 IRQ_NOPROBE); 470 } 471 get_device(&trig->dev); 472 } 473 return trig; 474 } 475 EXPORT_SYMBOL(iio_trigger_alloc); 476 477 void iio_trigger_free(struct iio_trigger *trig) 478 { 479 if (trig) 480 put_device(&trig->dev); 481 } 482 EXPORT_SYMBOL(iio_trigger_free); 483 484 void iio_device_register_trigger_consumer(struct iio_dev *indio_dev) 485 { 486 indio_dev->groups[indio_dev->groupcounter++] = 487 &iio_trigger_consumer_attr_group; 488 } 489 490 void iio_device_unregister_trigger_consumer(struct iio_dev *indio_dev) 491 { 492 /* Clean up and associated but not attached triggers references */ 493 if (indio_dev->trig) 494 iio_trigger_put(indio_dev->trig); 495 } 496 497 int iio_triggered_buffer_postenable(struct iio_dev *indio_dev) 498 { 499 return iio_trigger_attach_poll_func(indio_dev->trig, 500 indio_dev->pollfunc); 501 } 502 EXPORT_SYMBOL(iio_triggered_buffer_postenable); 503 504 int iio_triggered_buffer_predisable(struct iio_dev *indio_dev) 505 { 506 return iio_trigger_dettach_poll_func(indio_dev->trig, 507 indio_dev->pollfunc); 508 } 509 EXPORT_SYMBOL(iio_triggered_buffer_predisable); 510