drivers/iio/industrialio-trigger.c

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