drivers/iio/industrialio-event.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* Industrial I/O event handling
   3  *
   4  * Copyright (c) 2008 Jonathan Cameron
   5  *
   6  * Based on elements of hwmon and input subsystems.
   7  */
   8
   9 #include <linux/anon_inodes.h>
  10 #include <linux/device.h>
  11 #include <linux/fs.h>
  12 #include <linux/kernel.h>
  13 #include <linux/kfifo.h>
  14 #include <linux/module.h>
  15 #include <linux/poll.h>
  16 #include <linux/sched.h>
  17 #include <linux/slab.h>
  18 #include <linux/uaccess.h>
  19 #include <linux/wait.h>
  20 #include <linux/iio/iio.h>
  21 #include <linux/iio/iio-opaque.h>
  22 #include "iio_core.h"
  23 #include <linux/iio/sysfs.h>
  24 #include <linux/iio/events.h>
  25
  26 /**
  27  * struct iio_event_interface - chrdev interface for an event line
  28  * @wait:               wait queue to allow blocking reads of events
  29  * @det_events:         list of detected events
  30  * @dev_attr_list:      list of event interface sysfs attribute
  31  * @flags:              file operations related flags including busy flag.
  32  * @group:              event interface sysfs attribute group
  33  * @read_lock:          lock to protect kfifo read operations
  34  * @ioctl_handler:      handler for event ioctl() calls
  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         struct mutex            read_lock;
  44         struct iio_ioctl_handler        ioctl_handler;
  45 };
  46
  47 bool iio_event_enabled(const struct iio_event_interface *ev_int)
  48 {
  49         return !!test_bit(IIO_BUSY_BIT_POS, &ev_int->flags);
  50 }
  51
  52 /**
  53  * iio_push_event() - try to add event to the list for userspace reading
  54  * @indio_dev:          IIO device structure
  55  * @ev_code:            What event
  56  * @timestamp:          When the event occurred
  57  *
  58  * Note: The caller must make sure that this function is not running
  59  * concurrently for the same indio_dev more than once.
  60  *
  61  * This function may be safely used as soon as a valid reference to iio_dev has
  62  * been obtained via iio_device_alloc(), but any events that are submitted
  63  * before iio_device_register() has successfully completed will be silently
  64  * discarded.
  65  **/
  66 int iio_push_event(struct iio_dev *indio_dev, u64 ev_code, s64 timestamp)
  67 {
  68         struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
  69         struct iio_event_interface *ev_int = iio_dev_opaque->event_interface;
  70         struct iio_event_data ev;
  71         int copied;
  72
  73         if (!ev_int)
  74                 return 0;
  75
  76         /* Does anyone care? */
  77         if (iio_event_enabled(ev_int)) {
  78
  79                 ev.id = ev_code;
  80                 ev.timestamp = timestamp;
  81
  82                 copied = kfifo_put(&ev_int->det_events, ev);
  83                 if (copied != 0)
  84                         wake_up_poll(&ev_int->wait, EPOLLIN);
  85         }
  86
  87         return 0;
  88 }
  89 EXPORT_SYMBOL(iio_push_event);
  90
  91 /**
  92  * iio_event_poll() - poll the event queue to find out if it has data
  93  * @filep:      File structure pointer to identify the device
  94  * @wait:       Poll table pointer to add the wait queue on
  95  *
  96  * Return: (EPOLLIN | EPOLLRDNORM) if data is available for reading
  97  *         or a negative error code on failure
  98  */
  99 static __poll_t iio_event_poll(struct file *filep,
 100                              struct poll_table_struct *wait)
 101 {
 102         struct iio_dev *indio_dev = filep->private_data;
 103         struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
 104         struct iio_event_interface *ev_int = iio_dev_opaque->event_interface;
 105         __poll_t events = 0;
 106
 107         if (!indio_dev->info)
 108                 return events;
 109
 110         poll_wait(filep, &ev_int->wait, wait);
 111
 112         if (!kfifo_is_empty(&ev_int->det_events))
 113                 events = EPOLLIN | EPOLLRDNORM;
 114
 115         return events;
 116 }
 117
 118 static ssize_t iio_event_chrdev_read(struct file *filep,
 119                                      char __user *buf,
 120                                      size_t count,
 121                                      loff_t *f_ps)
 122 {
 123         struct iio_dev *indio_dev = filep->private_data;
 124         struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
 125         struct iio_event_interface *ev_int = iio_dev_opaque->event_interface;
 126         unsigned int copied;
 127         int ret;
 128
 129         if (!indio_dev->info)
 130                 return -ENODEV;
 131
 132         if (count < sizeof(struct iio_event_data))
 133                 return -EINVAL;
 134
 135         do {
 136                 if (kfifo_is_empty(&ev_int->det_events)) {
 137                         if (filep->f_flags & O_NONBLOCK)
 138                                 return -EAGAIN;
 139
 140                         ret = wait_event_interruptible(ev_int->wait,
 141                                         !kfifo_is_empty(&ev_int->det_events) ||
 142                                         indio_dev->info == NULL);
 143                         if (ret)
 144                                 return ret;
 145                         if (indio_dev->info == NULL)
 146                                 return -ENODEV;
 147                 }
 148
 149                 if (mutex_lock_interruptible(&ev_int->read_lock))
 150                         return -ERESTARTSYS;
 151                 ret = kfifo_to_user(&ev_int->det_events, buf, count, &copied);
 152                 mutex_unlock(&ev_int->read_lock);
 153
 154                 if (ret)
 155                         return ret;
 156
 157                 /*
 158                  * If we couldn't read anything from the fifo (a different
 159                  * thread might have been faster) we either return -EAGAIN if
 160                  * the file descriptor is non-blocking, otherwise we go back to
 161                  * sleep and wait for more data to arrive.
 162                  */
 163                 if (copied == 0 && (filep->f_flags & O_NONBLOCK))
 164                         return -EAGAIN;
 165
 166         } while (copied == 0);
 167
 168         return copied;
 169 }
 170
 171 static int iio_event_chrdev_release(struct inode *inode, struct file *filep)
 172 {
 173         struct iio_dev *indio_dev = filep->private_data;
 174         struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
 175         struct iio_event_interface *ev_int = iio_dev_opaque->event_interface;
 176
 177         clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags);
 178
 179         iio_device_put(indio_dev);
 180
 181         return 0;
 182 }
 183
 184 static const struct file_operations iio_event_chrdev_fileops = {
 185         .read =  iio_event_chrdev_read,
 186         .poll =  iio_event_poll,
 187         .release = iio_event_chrdev_release,
 188         .owner = THIS_MODULE,
 189         .llseek = noop_llseek,
 190 };
 191
 192 static int iio_event_getfd(struct iio_dev *indio_dev)
 193 {
 194         struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
 195         struct iio_event_interface *ev_int = iio_dev_opaque->event_interface;
 196         int fd;
 197
 198         if (ev_int == NULL)
 199                 return -ENODEV;
 200
 201         fd = mutex_lock_interruptible(&iio_dev_opaque->mlock);
 202         if (fd)
 203                 return fd;
 204
 205         if (test_and_set_bit(IIO_BUSY_BIT_POS, &ev_int->flags)) {
 206                 fd = -EBUSY;
 207                 goto unlock;
 208         }
 209
 210         iio_device_get(indio_dev);
 211
 212         fd = anon_inode_getfd("iio:event", &iio_event_chrdev_fileops,
 213                                 indio_dev, O_RDONLY | O_CLOEXEC);
 214         if (fd < 0) {
 215                 clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags);
 216                 iio_device_put(indio_dev);
 217         } else {
 218                 kfifo_reset_out(&ev_int->det_events);
 219         }
 220
 221 unlock:
 222         mutex_unlock(&iio_dev_opaque->mlock);
 223         return fd;
 224 }
 225
 226 static const char * const iio_ev_type_text[] = {
 227         [IIO_EV_TYPE_THRESH] = "thresh",
 228         [IIO_EV_TYPE_MAG] = "mag",
 229         [IIO_EV_TYPE_ROC] = "roc",
 230         [IIO_EV_TYPE_THRESH_ADAPTIVE] = "thresh_adaptive",
 231         [IIO_EV_TYPE_MAG_ADAPTIVE] = "mag_adaptive",
 232         [IIO_EV_TYPE_CHANGE] = "change",
 233         [IIO_EV_TYPE_MAG_REFERENCED] = "mag_referenced",
 234         [IIO_EV_TYPE_GESTURE] = "gesture",
 235 };
 236
 237 static const char * const iio_ev_dir_text[] = {
 238         [IIO_EV_DIR_EITHER] = "either",
 239         [IIO_EV_DIR_RISING] = "rising",
 240         [IIO_EV_DIR_FALLING] = "falling",
 241         [IIO_EV_DIR_SINGLETAP] = "singletap",
 242         [IIO_EV_DIR_DOUBLETAP] = "doubletap",
 243 };
 244
 245 static const char * const iio_ev_info_text[] = {
 246         [IIO_EV_INFO_ENABLE] = "en",
 247         [IIO_EV_INFO_VALUE] = "value",
 248         [IIO_EV_INFO_HYSTERESIS] = "hysteresis",
 249         [IIO_EV_INFO_PERIOD] = "period",
 250         [IIO_EV_INFO_HIGH_PASS_FILTER_3DB] = "high_pass_filter_3db",
 251         [IIO_EV_INFO_LOW_PASS_FILTER_3DB] = "low_pass_filter_3db",
 252         [IIO_EV_INFO_TIMEOUT] = "timeout",
 253         [IIO_EV_INFO_RESET_TIMEOUT] = "reset_timeout",
 254         [IIO_EV_INFO_TAP2_MIN_DELAY] = "tap2_min_delay",
 255         [IIO_EV_INFO_RUNNING_PERIOD] = "runningperiod",
 256         [IIO_EV_INFO_RUNNING_COUNT] = "runningcount",
 257 };
 258
 259 static enum iio_event_direction iio_ev_attr_dir(struct iio_dev_attr *attr)
 260 {
 261         return attr->c->event_spec[attr->address & 0xffff].dir;
 262 }
 263
 264 static enum iio_event_type iio_ev_attr_type(struct iio_dev_attr *attr)
 265 {
 266         return attr->c->event_spec[attr->address & 0xffff].type;
 267 }
 268
 269 static enum iio_event_info iio_ev_attr_info(struct iio_dev_attr *attr)
 270 {
 271         return (attr->address >> 16) & 0xffff;
 272 }
 273
 274 static ssize_t iio_ev_state_store(struct device *dev,
 275                                   struct device_attribute *attr,
 276                                   const char *buf,
 277                                   size_t len)
 278 {
 279         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 280         struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
 281         int ret;
 282         bool val;
 283
 284         ret = kstrtobool(buf, &val);
 285         if (ret < 0)
 286                 return ret;
 287
 288         if (!indio_dev->info->write_event_config)
 289                 return -EINVAL;
 290
 291         ret = indio_dev->info->write_event_config(indio_dev,
 292                 this_attr->c, iio_ev_attr_type(this_attr),
 293                 iio_ev_attr_dir(this_attr), val);
 294
 295         return (ret < 0) ? ret : len;
 296 }
 297
 298 static ssize_t iio_ev_state_show(struct device *dev,
 299                                  struct device_attribute *attr,
 300                                  char *buf)
 301 {
 302         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 303         struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
 304         int val;
 305
 306         if (!indio_dev->info->read_event_config)
 307                 return -EINVAL;
 308
 309         val = indio_dev->info->read_event_config(indio_dev,
 310                 this_attr->c, iio_ev_attr_type(this_attr),
 311                 iio_ev_attr_dir(this_attr));
 312         if (val < 0)
 313                 return val;
 314         else
 315                 return sysfs_emit(buf, "%d\n", val);
 316 }
 317
 318 static ssize_t iio_ev_value_show(struct device *dev,
 319                                  struct device_attribute *attr,
 320                                  char *buf)
 321 {
 322         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 323         struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
 324         int val, val2, val_arr[2];
 325         int ret;
 326
 327         if (!indio_dev->info->read_event_value)
 328                 return -EINVAL;
 329
 330         ret = indio_dev->info->read_event_value(indio_dev,
 331                 this_attr->c, iio_ev_attr_type(this_attr),
 332                 iio_ev_attr_dir(this_attr), iio_ev_attr_info(this_attr),
 333                 &val, &val2);
 334         if (ret < 0)
 335                 return ret;
 336         val_arr[0] = val;
 337         val_arr[1] = val2;
 338         return iio_format_value(buf, ret, 2, val_arr);
 339 }
 340
 341 static ssize_t iio_ev_value_store(struct device *dev,
 342                                   struct device_attribute *attr,
 343                                   const char *buf,
 344                                   size_t len)
 345 {
 346         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 347         struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
 348         int val, val2;
 349         int ret;
 350
 351         if (!indio_dev->info->write_event_value)
 352                 return -EINVAL;
 353
 354         ret = iio_str_to_fixpoint(buf, 100000, &val, &val2);
 355         if (ret)
 356                 return ret;
 357         ret = indio_dev->info->write_event_value(indio_dev,
 358                 this_attr->c, iio_ev_attr_type(this_attr),
 359                 iio_ev_attr_dir(this_attr), iio_ev_attr_info(this_attr),
 360                 val, val2);
 361         if (ret < 0)
 362                 return ret;
 363
 364         return len;
 365 }
 366
 367 static ssize_t iio_ev_label_show(struct device *dev,
 368                                  struct device_attribute *attr,
 369                                  char *buf)
 370 {
 371         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 372         struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
 373
 374         if (indio_dev->info->read_event_label)
 375                 return indio_dev->info->read_event_label(indio_dev,
 376                                  this_attr->c, iio_ev_attr_type(this_attr),
 377                                  iio_ev_attr_dir(this_attr), buf);
 378
 379         return -EINVAL;
 380 }
 381
 382 static int iio_device_add_event(struct iio_dev *indio_dev,
 383         const struct iio_chan_spec *chan, unsigned int spec_index,
 384         enum iio_event_type type, enum iio_event_direction dir,
 385         enum iio_shared_by shared_by, const unsigned long *mask)
 386 {
 387         struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
 388         ssize_t (*show)(struct device *dev, struct device_attribute *attr,
 389                 char *buf);
 390         ssize_t (*store)(struct device *dev, struct device_attribute *attr,
 391                 const char *buf, size_t len);
 392         unsigned int attrcount = 0;
 393         unsigned int i;
 394         char *postfix;
 395         int ret;
 396
 397         for_each_set_bit(i, mask, sizeof(*mask)*8) {
 398                 if (i >= ARRAY_SIZE(iio_ev_info_text))
 399                         return -EINVAL;
 400                 if (dir != IIO_EV_DIR_NONE)
 401                         postfix = kasprintf(GFP_KERNEL, "%s_%s_%s",
 402                                         iio_ev_type_text[type],
 403                                         iio_ev_dir_text[dir],
 404                                         iio_ev_info_text[i]);
 405                 else
 406                         postfix = kasprintf(GFP_KERNEL, "%s_%s",
 407                                         iio_ev_type_text[type],
 408                                         iio_ev_info_text[i]);
 409                 if (postfix == NULL)
 410                         return -ENOMEM;
 411
 412                 if (i == IIO_EV_INFO_ENABLE) {
 413                         show = iio_ev_state_show;
 414                         store = iio_ev_state_store;
 415                 } else {
 416                         show = iio_ev_value_show;
 417                         store = iio_ev_value_store;
 418                 }
 419
 420                 ret = __iio_add_chan_devattr(postfix, chan, show, store,
 421                          (i << 16) | spec_index, shared_by, &indio_dev->dev,
 422                          NULL,
 423                         &iio_dev_opaque->event_interface->dev_attr_list);
 424                 kfree(postfix);
 425
 426                 if ((ret == -EBUSY) && (shared_by != IIO_SEPARATE))
 427                         continue;
 428
 429                 if (ret)
 430                         return ret;
 431
 432                 attrcount++;
 433         }
 434
 435         return attrcount;
 436 }
 437
 438 static int iio_device_add_event_label(struct iio_dev *indio_dev,
 439                                       const struct iio_chan_spec *chan,
 440                                       unsigned int spec_index,
 441                                       enum iio_event_type type,
 442                                       enum iio_event_direction dir)
 443 {
 444         struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
 445         char *postfix;
 446         int ret;
 447
 448         if (!indio_dev->info->read_event_label)
 449                 return 0;
 450
 451         if (dir != IIO_EV_DIR_NONE)
 452                 postfix = kasprintf(GFP_KERNEL, "%s_%s_label",
 453                                 iio_ev_type_text[type],
 454                                 iio_ev_dir_text[dir]);
 455         else
 456                 postfix = kasprintf(GFP_KERNEL, "%s_label",
 457                                 iio_ev_type_text[type]);
 458         if (postfix == NULL)
 459                 return -ENOMEM;
 460
 461         ret = __iio_add_chan_devattr(postfix, chan, &iio_ev_label_show, NULL,
 462                                 spec_index, IIO_SEPARATE, &indio_dev->dev, NULL,
 463                                 &iio_dev_opaque->event_interface->dev_attr_list);
 464
 465         kfree(postfix);
 466
 467         if (ret < 0)
 468                 return ret;
 469
 470         return 1;
 471 }
 472
 473 static int iio_device_add_event_sysfs(struct iio_dev *indio_dev,
 474         struct iio_chan_spec const *chan)
 475 {
 476         int ret = 0, i, attrcount = 0;
 477         enum iio_event_direction dir;
 478         enum iio_event_type type;
 479
 480         for (i = 0; i < chan->num_event_specs; i++) {
 481                 type = chan->event_spec[i].type;
 482                 dir = chan->event_spec[i].dir;
 483
 484                 ret = iio_device_add_event(indio_dev, chan, i, type, dir,
 485                         IIO_SEPARATE, &chan->event_spec[i].mask_separate);
 486                 if (ret < 0)
 487                         return ret;
 488                 attrcount += ret;
 489
 490                 ret = iio_device_add_event(indio_dev, chan, i, type, dir,
 491                         IIO_SHARED_BY_TYPE,
 492                         &chan->event_spec[i].mask_shared_by_type);
 493                 if (ret < 0)
 494                         return ret;
 495                 attrcount += ret;
 496
 497                 ret = iio_device_add_event(indio_dev, chan, i, type, dir,
 498                         IIO_SHARED_BY_DIR,
 499                         &chan->event_spec[i].mask_shared_by_dir);
 500                 if (ret < 0)
 501                         return ret;
 502                 attrcount += ret;
 503
 504                 ret = iio_device_add_event(indio_dev, chan, i, type, dir,
 505                         IIO_SHARED_BY_ALL,
 506                         &chan->event_spec[i].mask_shared_by_all);
 507                 if (ret < 0)
 508                         return ret;
 509                 attrcount += ret;
 510
 511                 ret = iio_device_add_event_label(indio_dev, chan, i, type, dir);
 512                 if (ret < 0)
 513                         return ret;
 514                 attrcount += ret;
 515         }
 516         ret = attrcount;
 517         return ret;
 518 }
 519
 520 static inline int __iio_add_event_config_attrs(struct iio_dev *indio_dev)
 521 {
 522         int j, ret, attrcount = 0;
 523
 524         /* Dynamically created from the channels array */
 525         for (j = 0; j < indio_dev->num_channels; j++) {
 526                 ret = iio_device_add_event_sysfs(indio_dev,
 527                                                  &indio_dev->channels[j]);
 528                 if (ret < 0)
 529                         return ret;
 530                 attrcount += ret;
 531         }
 532         return attrcount;
 533 }
 534
 535 static bool iio_check_for_dynamic_events(struct iio_dev *indio_dev)
 536 {
 537         int j;
 538
 539         for (j = 0; j < indio_dev->num_channels; j++) {
 540                 if (indio_dev->channels[j].num_event_specs != 0)
 541                         return true;
 542         }
 543         return false;
 544 }
 545
 546 static void iio_setup_ev_int(struct iio_event_interface *ev_int)
 547 {
 548         INIT_KFIFO(ev_int->det_events);
 549         init_waitqueue_head(&ev_int->wait);
 550         mutex_init(&ev_int->read_lock);
 551 }
 552
 553 static long iio_event_ioctl(struct iio_dev *indio_dev, struct file *filp,
 554                             unsigned int cmd, unsigned long arg)
 555 {
 556         int __user *ip = (int __user *)arg;
 557         int fd;
 558
 559         if (cmd == IIO_GET_EVENT_FD_IOCTL) {
 560                 fd = iio_event_getfd(indio_dev);
 561                 if (fd < 0)
 562                         return fd;
 563                 if (copy_to_user(ip, &fd, sizeof(fd)))
 564                         return -EFAULT;
 565                 return 0;
 566         }
 567
 568         return IIO_IOCTL_UNHANDLED;
 569 }
 570
 571 static const char *iio_event_group_name = "events";
 572 int iio_device_register_eventset(struct iio_dev *indio_dev)
 573 {
 574         struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
 575         struct iio_event_interface *ev_int;
 576         struct iio_dev_attr *p;
 577         int ret = 0, attrcount_orig = 0, attrcount, attrn;
 578         struct attribute **attr;
 579
 580         if (!(indio_dev->info->event_attrs ||
 581               iio_check_for_dynamic_events(indio_dev)))
 582                 return 0;
 583
 584         ev_int = kzalloc(sizeof(*ev_int), GFP_KERNEL);
 585         if (!ev_int)
 586                 return -ENOMEM;
 587
 588         iio_dev_opaque->event_interface = ev_int;
 589
 590         INIT_LIST_HEAD(&ev_int->dev_attr_list);
 591
 592         iio_setup_ev_int(ev_int);
 593         if (indio_dev->info->event_attrs != NULL) {
 594                 attr = indio_dev->info->event_attrs->attrs;
 595                 while (*attr++ != NULL)
 596                         attrcount_orig++;
 597         }
 598         attrcount = attrcount_orig;
 599         if (indio_dev->channels) {
 600                 ret = __iio_add_event_config_attrs(indio_dev);
 601                 if (ret < 0)
 602                         goto error_free_setup_event_lines;
 603                 attrcount += ret;
 604         }
 605
 606         ev_int->group.name = iio_event_group_name;
 607         ev_int->group.attrs = kcalloc(attrcount + 1,
 608                                       sizeof(ev_int->group.attrs[0]),
 609                                       GFP_KERNEL);
 610         if (ev_int->group.attrs == NULL) {
 611                 ret = -ENOMEM;
 612                 goto error_free_setup_event_lines;
 613         }
 614         if (indio_dev->info->event_attrs)
 615                 memcpy(ev_int->group.attrs,
 616                        indio_dev->info->event_attrs->attrs,
 617                        sizeof(ev_int->group.attrs[0]) * attrcount_orig);
 618         attrn = attrcount_orig;
 619         /* Add all elements from the list. */
 620         list_for_each_entry(p, &ev_int->dev_attr_list, l)
 621                 ev_int->group.attrs[attrn++] = &p->dev_attr.attr;
 622
 623         ret = iio_device_register_sysfs_group(indio_dev, &ev_int->group);
 624         if (ret)
 625                 goto error_free_group_attrs;
 626
 627         ev_int->ioctl_handler.ioctl = iio_event_ioctl;
 628         iio_device_ioctl_handler_register(&iio_dev_opaque->indio_dev,
 629                                           &ev_int->ioctl_handler);
 630
 631         return 0;
 632
 633 error_free_group_attrs:
 634         kfree(ev_int->group.attrs);
 635 error_free_setup_event_lines:
 636         iio_free_chan_devattr_list(&ev_int->dev_attr_list);
 637         kfree(ev_int);
 638         iio_dev_opaque->event_interface = NULL;
 639         return ret;
 640 }
 641
 642 /**
 643  * iio_device_wakeup_eventset - Wakes up the event waitqueue
 644  * @indio_dev: The IIO device
 645  *
 646  * Wakes up the event waitqueue used for poll() and blocking read().
 647  * Should usually be called when the device is unregistered.
 648  */
 649 void iio_device_wakeup_eventset(struct iio_dev *indio_dev)
 650 {
 651         struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
 652
 653         if (iio_dev_opaque->event_interface == NULL)
 654                 return;
 655         wake_up(&iio_dev_opaque->event_interface->wait);
 656 }
 657
 658 void iio_device_unregister_eventset(struct iio_dev *indio_dev)
 659 {
 660         struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
 661         struct iio_event_interface *ev_int = iio_dev_opaque->event_interface;
 662
 663         if (ev_int == NULL)
 664                 return;
 665
 666         iio_device_ioctl_handler_unregister(&ev_int->ioctl_handler);
 667         iio_free_chan_devattr_list(&ev_int->dev_attr_list);
 668         kfree(ev_int->group.attrs);
 669         kfree(ev_int);
 670         iio_dev_opaque->event_interface = NULL;
 671 }