drivers/iio/industrialio-event.c

   1 /* Industrial I/O event handling
   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  * Based on elements of hwmon and input subsystems.
  10  */
  11
  12 #include <linux/anon_inodes.h>
  13 #include <linux/device.h>
  14 #include <linux/fs.h>
  15 #include <linux/kernel.h>
  16 #include <linux/kfifo.h>
  17 #include <linux/module.h>
  18 #include <linux/poll.h>
  19 #include <linux/sched.h>
  20 #include <linux/slab.h>
  21 #include <linux/uaccess.h>
  22 #include <linux/wait.h>
  23 #include <linux/iio/iio.h>
  24 #include "iio_core.h"
  25 #include <linux/iio/sysfs.h>
  26 #include <linux/iio/events.h>
  27
  28 /**
  29  * struct iio_event_interface - chrdev interface for an event line
  30  * @wait:               wait queue to allow blocking reads of events
  31  * @det_events:         list of detected events
  32  * @dev_attr_list:      list of event interface sysfs attribute
  33  * @flags:              file operations related flags including busy flag.
  34  * @group:              event interface sysfs attribute group
  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 };
  44
  45 int iio_push_event(struct iio_dev *indio_dev, u64 ev_code, s64 timestamp)
  46 {
  47         struct iio_event_interface *ev_int = indio_dev->event_interface;
  48         struct iio_event_data ev;
  49         unsigned long flags;
  50         int copied;
  51
  52         /* Does anyone care? */
  53         spin_lock_irqsave(&ev_int->wait.lock, flags);
  54         if (test_bit(IIO_BUSY_BIT_POS, &ev_int->flags)) {
  55
  56                 ev.id = ev_code;
  57                 ev.timestamp = timestamp;
  58
  59                 copied = kfifo_put(&ev_int->det_events, ev);
  60                 if (copied != 0)
  61                         wake_up_locked_poll(&ev_int->wait, POLLIN);
  62         }
  63         spin_unlock_irqrestore(&ev_int->wait.lock, flags);
  64
  65         return 0;
  66 }
  67 EXPORT_SYMBOL(iio_push_event);
  68
  69 /**
  70  * iio_event_poll() - poll the event queue to find out if it has data
  71  */
  72 static unsigned int iio_event_poll(struct file *filep,
  73                              struct poll_table_struct *wait)
  74 {
  75         struct iio_dev *indio_dev = filep->private_data;
  76         struct iio_event_interface *ev_int = indio_dev->event_interface;
  77         unsigned int events = 0;
  78
  79         if (!indio_dev->info)
  80                 return -ENODEV;
  81
  82         poll_wait(filep, &ev_int->wait, wait);
  83
  84         spin_lock_irq(&ev_int->wait.lock);
  85         if (!kfifo_is_empty(&ev_int->det_events))
  86                 events = POLLIN | POLLRDNORM;
  87         spin_unlock_irq(&ev_int->wait.lock);
  88
  89         return events;
  90 }
  91
  92 static ssize_t iio_event_chrdev_read(struct file *filep,
  93                                      char __user *buf,
  94                                      size_t count,
  95                                      loff_t *f_ps)
  96 {
  97         struct iio_dev *indio_dev = filep->private_data;
  98         struct iio_event_interface *ev_int = indio_dev->event_interface;
  99         unsigned int copied;
 100         int ret;
 101
 102         if (!indio_dev->info)
 103                 return -ENODEV;
 104
 105         if (count < sizeof(struct iio_event_data))
 106                 return -EINVAL;
 107
 108         spin_lock_irq(&ev_int->wait.lock);
 109         if (kfifo_is_empty(&ev_int->det_events)) {
 110                 if (filep->f_flags & O_NONBLOCK) {
 111                         ret = -EAGAIN;
 112                         goto error_unlock;
 113                 }
 114                 /* Blocking on device; waiting for something to be there */
 115                 ret = wait_event_interruptible_locked_irq(ev_int->wait,
 116                                         !kfifo_is_empty(&ev_int->det_events) ||
 117                                         indio_dev->info == NULL);
 118                 if (ret)
 119                         goto error_unlock;
 120                 if (indio_dev->info == NULL) {
 121                         ret = -ENODEV;
 122                         goto error_unlock;
 123                 }
 124                 /* Single access device so no one else can get the data */
 125         }
 126
 127         ret = kfifo_to_user(&ev_int->det_events, buf, count, &copied);
 128
 129 error_unlock:
 130         spin_unlock_irq(&ev_int->wait.lock);
 131
 132         return ret ? ret : copied;
 133 }
 134
 135 static int iio_event_chrdev_release(struct inode *inode, struct file *filep)
 136 {
 137         struct iio_dev *indio_dev = filep->private_data;
 138         struct iio_event_interface *ev_int = indio_dev->event_interface;
 139
 140         spin_lock_irq(&ev_int->wait.lock);
 141         __clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags);
 142         /*
 143          * In order to maintain a clean state for reopening,
 144          * clear out any awaiting events. The mask will prevent
 145          * any new __iio_push_event calls running.
 146          */
 147         kfifo_reset_out(&ev_int->det_events);
 148         spin_unlock_irq(&ev_int->wait.lock);
 149
 150         iio_device_put(indio_dev);
 151
 152         return 0;
 153 }
 154
 155 static const struct file_operations iio_event_chrdev_fileops = {
 156         .read =  iio_event_chrdev_read,
 157         .poll =  iio_event_poll,
 158         .release = iio_event_chrdev_release,
 159         .owner = THIS_MODULE,
 160         .llseek = noop_llseek,
 161 };
 162
 163 int iio_event_getfd(struct iio_dev *indio_dev)
 164 {
 165         struct iio_event_interface *ev_int = indio_dev->event_interface;
 166         int fd;
 167
 168         if (ev_int == NULL)
 169                 return -ENODEV;
 170
 171         spin_lock_irq(&ev_int->wait.lock);
 172         if (__test_and_set_bit(IIO_BUSY_BIT_POS, &ev_int->flags)) {
 173                 spin_unlock_irq(&ev_int->wait.lock);
 174                 return -EBUSY;
 175         }
 176         spin_unlock_irq(&ev_int->wait.lock);
 177         iio_device_get(indio_dev);
 178
 179         fd = anon_inode_getfd("iio:event", &iio_event_chrdev_fileops,
 180                                 indio_dev, O_RDONLY | O_CLOEXEC);
 181         if (fd < 0) {
 182                 spin_lock_irq(&ev_int->wait.lock);
 183                 __clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags);
 184                 spin_unlock_irq(&ev_int->wait.lock);
 185                 iio_device_put(indio_dev);
 186         }
 187         return fd;
 188 }
 189
 190 static const char * const iio_ev_type_text[] = {
 191         [IIO_EV_TYPE_THRESH] = "thresh",
 192         [IIO_EV_TYPE_MAG] = "mag",
 193         [IIO_EV_TYPE_ROC] = "roc",
 194         [IIO_EV_TYPE_THRESH_ADAPTIVE] = "thresh_adaptive",
 195         [IIO_EV_TYPE_MAG_ADAPTIVE] = "mag_adaptive",
 196 };
 197
 198 static const char * const iio_ev_dir_text[] = {
 199         [IIO_EV_DIR_EITHER] = "either",
 200         [IIO_EV_DIR_RISING] = "rising",
 201         [IIO_EV_DIR_FALLING] = "falling"
 202 };
 203
 204 static const char * const iio_ev_info_text[] = {
 205         [IIO_EV_INFO_ENABLE] = "en",
 206         [IIO_EV_INFO_VALUE] = "value",
 207         [IIO_EV_INFO_HYSTERESIS] = "hysteresis",
 208 };
 209
 210 static enum iio_event_direction iio_ev_attr_dir(struct iio_dev_attr *attr)
 211 {
 212         return attr->c->event_spec[attr->address & 0xffff].dir;
 213 }
 214
 215 static enum iio_event_type iio_ev_attr_type(struct iio_dev_attr *attr)
 216 {
 217         return attr->c->event_spec[attr->address & 0xffff].type;
 218 }
 219
 220 static enum iio_event_info iio_ev_attr_info(struct iio_dev_attr *attr)
 221 {
 222         return (attr->address >> 16) & 0xffff;
 223 }
 224
 225 static ssize_t iio_ev_state_store(struct device *dev,
 226                                   struct device_attribute *attr,
 227                                   const char *buf,
 228                                   size_t len)
 229 {
 230         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 231         struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
 232         int ret;
 233         bool val;
 234
 235         ret = strtobool(buf, &val);
 236         if (ret < 0)
 237                 return ret;
 238
 239         if (indio_dev->info->write_event_config)
 240                 ret = indio_dev->info->write_event_config(indio_dev,
 241                         this_attr->address, val);
 242         else
 243                 ret = indio_dev->info->write_event_config_new(indio_dev,
 244                         this_attr->c, iio_ev_attr_type(this_attr),
 245                         iio_ev_attr_dir(this_attr), val);
 246
 247         return (ret < 0) ? ret : len;
 248 }
 249
 250 static ssize_t iio_ev_state_show(struct device *dev,
 251                                  struct device_attribute *attr,
 252                                  char *buf)
 253 {
 254         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 255         struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
 256         int val;
 257
 258         if (indio_dev->info->read_event_config)
 259                 val = indio_dev->info->read_event_config(indio_dev,
 260                         this_attr->address);
 261         else
 262                 val = indio_dev->info->read_event_config_new(indio_dev,
 263                         this_attr->c, iio_ev_attr_type(this_attr),
 264                         iio_ev_attr_dir(this_attr));
 265         if (val < 0)
 266                 return val;
 267         else
 268                 return sprintf(buf, "%d\n", val);
 269 }
 270
 271 static ssize_t iio_ev_value_show(struct device *dev,
 272                                  struct device_attribute *attr,
 273                                  char *buf)
 274 {
 275         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 276         struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
 277         int val, val2;
 278         int ret;
 279
 280         if (indio_dev->info->read_event_value) {
 281                 ret = indio_dev->info->read_event_value(indio_dev,
 282                         this_attr->address, &val);
 283                 if (ret < 0)
 284                         return ret;
 285                 return sprintf(buf, "%d\n", val);
 286         } else {
 287                 ret = indio_dev->info->read_event_value_new(indio_dev,
 288                         this_attr->c, iio_ev_attr_type(this_attr),
 289                         iio_ev_attr_dir(this_attr), iio_ev_attr_info(this_attr),
 290                         &val, &val2);
 291                 if (ret < 0)
 292                         return ret;
 293                 return iio_format_value(buf, ret, val, val2);
 294         }
 295 }
 296
 297 static ssize_t iio_ev_value_store(struct device *dev,
 298                                   struct device_attribute *attr,
 299                                   const char *buf,
 300                                   size_t len)
 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, val2;
 305         int ret;
 306
 307         if (!indio_dev->info->write_event_value &&
 308                 !indio_dev->info->write_event_value_new)
 309                 return -EINVAL;
 310
 311         if (indio_dev->info->write_event_value) {
 312                 ret = kstrtoint(buf, 10, &val);
 313                 if (ret)
 314                         return ret;
 315                 ret = indio_dev->info->write_event_value(indio_dev,
 316                         this_attr->address, val);
 317         } else {
 318                 ret = iio_str_to_fixpoint(buf, 100000, &val, &val2);
 319                 if (ret)
 320                         return ret;
 321                 ret = indio_dev->info->write_event_value_new(indio_dev,
 322                         this_attr->c, iio_ev_attr_type(this_attr),
 323                         iio_ev_attr_dir(this_attr), iio_ev_attr_info(this_attr),
 324                         val, val2);
 325         }
 326         if (ret < 0)
 327                 return ret;
 328
 329         return len;
 330 }
 331
 332 static int iio_device_add_event(struct iio_dev *indio_dev,
 333         const struct iio_chan_spec *chan, unsigned int spec_index,
 334         enum iio_event_type type, enum iio_event_direction dir,
 335         enum iio_shared_by shared_by, const unsigned long *mask)
 336 {
 337         ssize_t (*show)(struct device *, struct device_attribute *, char *);
 338         ssize_t (*store)(struct device *, struct device_attribute *,
 339                 const char *, size_t);
 340         unsigned int attrcount = 0;
 341         unsigned int i;
 342         char *postfix;
 343         int ret;
 344
 345         for_each_set_bit(i, mask, sizeof(*mask)) {
 346                 postfix = kasprintf(GFP_KERNEL, "%s_%s_%s",
 347                                 iio_ev_type_text[type], iio_ev_dir_text[dir],
 348                                 iio_ev_info_text[i]);
 349                 if (postfix == NULL)
 350                         return -ENOMEM;
 351
 352                 if (i == IIO_EV_INFO_ENABLE) {
 353                         show = iio_ev_state_show;
 354                         store = iio_ev_state_store;
 355                 } else {
 356                         show = iio_ev_value_show;
 357                         store = iio_ev_value_store;
 358                 }
 359
 360                 ret = __iio_add_chan_devattr(postfix, chan, show, store,
 361                          (i << 16) | spec_index, shared_by, &indio_dev->dev,
 362                         &indio_dev->event_interface->dev_attr_list);
 363                 kfree(postfix);
 364
 365                 if (ret)
 366                         return ret;
 367
 368                 attrcount++;
 369         }
 370
 371         return attrcount;
 372 }
 373
 374 static int iio_device_add_event_sysfs_new(struct iio_dev *indio_dev,
 375         struct iio_chan_spec const *chan)
 376 {
 377         int ret = 0, i, attrcount = 0;
 378         enum iio_event_direction dir;
 379         enum iio_event_type type;
 380
 381         for (i = 0; i < chan->num_event_specs; i++) {
 382                 type = chan->event_spec[i].type;
 383                 dir = chan->event_spec[i].dir;
 384
 385                 ret = iio_device_add_event(indio_dev, chan, i, type, dir,
 386                         IIO_SEPARATE, &chan->event_spec[i].mask_separate);
 387                 if (ret < 0)
 388                         goto error_ret;
 389                 attrcount += ret;
 390
 391                 ret = iio_device_add_event(indio_dev, chan, i, type, dir,
 392                         IIO_SHARED_BY_TYPE,
 393                         &chan->event_spec[i].mask_shared_by_type);
 394                 if (ret < 0)
 395                         goto error_ret;
 396                 attrcount += ret;
 397
 398                 ret = iio_device_add_event(indio_dev, chan, i, type, dir,
 399                         IIO_SHARED_BY_DIR,
 400                         &chan->event_spec[i].mask_shared_by_dir);
 401                 if (ret < 0)
 402                         goto error_ret;
 403                 attrcount += ret;
 404
 405                 ret = iio_device_add_event(indio_dev, chan, i, type, dir,
 406                         IIO_SHARED_BY_ALL,
 407                         &chan->event_spec[i].mask_shared_by_all);
 408                 if (ret < 0)
 409                         goto error_ret;
 410                 attrcount += ret;
 411         }
 412         ret = attrcount;
 413 error_ret:
 414         return ret;
 415 }
 416
 417 static int iio_device_add_event_sysfs_old(struct iio_dev *indio_dev,
 418                                       struct iio_chan_spec const *chan)
 419 {
 420         int ret = 0, i, attrcount = 0;
 421         u64 mask = 0;
 422         char *postfix;
 423         if (!chan->event_mask)
 424                 return 0;
 425
 426         for_each_set_bit(i, &chan->event_mask, sizeof(chan->event_mask)*8) {
 427                 postfix = kasprintf(GFP_KERNEL, "%s_%s_en",
 428                                     iio_ev_type_text[i/IIO_EV_DIR_MAX],
 429                                     iio_ev_dir_text[i%IIO_EV_DIR_MAX]);
 430                 if (postfix == NULL) {
 431                         ret = -ENOMEM;
 432                         goto error_ret;
 433                 }
 434                 if (chan->modified)
 435                         mask = IIO_MOD_EVENT_CODE(chan->type, 0, chan->channel2,
 436                                                   i/IIO_EV_DIR_MAX,
 437                                                   i%IIO_EV_DIR_MAX);
 438                 else if (chan->differential)
 439                         mask = IIO_EVENT_CODE(chan->type,
 440                                               0, 0,
 441                                               i%IIO_EV_DIR_MAX,
 442                                               i/IIO_EV_DIR_MAX,
 443                                               0,
 444                                               chan->channel,
 445                                               chan->channel2);
 446                 else
 447                         mask = IIO_UNMOD_EVENT_CODE(chan->type,
 448                                                     chan->channel,
 449                                                     i/IIO_EV_DIR_MAX,
 450                                                     i%IIO_EV_DIR_MAX);
 451
 452                 ret = __iio_add_chan_devattr(postfix,
 453                                              chan,
 454                                              &iio_ev_state_show,
 455                                              iio_ev_state_store,
 456                                              mask,
 457                                              0,
 458                                              &indio_dev->dev,
 459                                              &indio_dev->event_interface->
 460                                              dev_attr_list);
 461                 kfree(postfix);
 462                 if (ret)
 463                         goto error_ret;
 464                 attrcount++;
 465                 postfix = kasprintf(GFP_KERNEL, "%s_%s_value",
 466                                     iio_ev_type_text[i/IIO_EV_DIR_MAX],
 467                                     iio_ev_dir_text[i%IIO_EV_DIR_MAX]);
 468                 if (postfix == NULL) {
 469                         ret = -ENOMEM;
 470                         goto error_ret;
 471                 }
 472                 ret = __iio_add_chan_devattr(postfix, chan,
 473                                              iio_ev_value_show,
 474                                              iio_ev_value_store,
 475                                              mask,
 476                                              0,
 477                                              &indio_dev->dev,
 478                                              &indio_dev->event_interface->
 479                                              dev_attr_list);
 480                 kfree(postfix);
 481                 if (ret)
 482                         goto error_ret;
 483                 attrcount++;
 484         }
 485         ret = attrcount;
 486 error_ret:
 487         return ret;
 488 }
 489
 490
 491 static int iio_device_add_event_sysfs(struct iio_dev *indio_dev,
 492                                       struct iio_chan_spec const *chan)
 493 {
 494         if (chan->event_mask)
 495                 return iio_device_add_event_sysfs_old(indio_dev, chan);
 496         else
 497                 return iio_device_add_event_sysfs_new(indio_dev, chan);
 498 }
 499
 500 static inline int __iio_add_event_config_attrs(struct iio_dev *indio_dev)
 501 {
 502         int j, ret, attrcount = 0;
 503
 504         /* Dynically created from the channels array */
 505         for (j = 0; j < indio_dev->num_channels; j++) {
 506                 ret = iio_device_add_event_sysfs(indio_dev,
 507                                                  &indio_dev->channels[j]);
 508                 if (ret < 0)
 509                         return ret;
 510                 attrcount += ret;
 511         }
 512         return attrcount;
 513 }
 514
 515 static bool iio_check_for_dynamic_events(struct iio_dev *indio_dev)
 516 {
 517         int j;
 518
 519         for (j = 0; j < indio_dev->num_channels; j++) {
 520                 if (indio_dev->channels[j].event_mask != 0)
 521                         return true;
 522                 if (indio_dev->channels[j].num_event_specs != 0)
 523                         return true;
 524         }
 525         return false;
 526 }
 527
 528 static void iio_setup_ev_int(struct iio_event_interface *ev_int)
 529 {
 530         INIT_KFIFO(ev_int->det_events);
 531         init_waitqueue_head(&ev_int->wait);
 532 }
 533
 534 static const char *iio_event_group_name = "events";
 535 int iio_device_register_eventset(struct iio_dev *indio_dev)
 536 {
 537         struct iio_dev_attr *p;
 538         int ret = 0, attrcount_orig = 0, attrcount, attrn;
 539         struct attribute **attr;
 540
 541         if (!(indio_dev->info->event_attrs ||
 542               iio_check_for_dynamic_events(indio_dev)))
 543                 return 0;
 544
 545         indio_dev->event_interface =
 546                 kzalloc(sizeof(struct iio_event_interface), GFP_KERNEL);
 547         if (indio_dev->event_interface == NULL) {
 548                 ret = -ENOMEM;
 549                 goto error_ret;
 550         }
 551
 552         INIT_LIST_HEAD(&indio_dev->event_interface->dev_attr_list);
 553
 554         iio_setup_ev_int(indio_dev->event_interface);
 555         if (indio_dev->info->event_attrs != NULL) {
 556                 attr = indio_dev->info->event_attrs->attrs;
 557                 while (*attr++ != NULL)
 558                         attrcount_orig++;
 559         }
 560         attrcount = attrcount_orig;
 561         if (indio_dev->channels) {
 562                 ret = __iio_add_event_config_attrs(indio_dev);
 563                 if (ret < 0)
 564                         goto error_free_setup_event_lines;
 565                 attrcount += ret;
 566         }
 567
 568         indio_dev->event_interface->group.name = iio_event_group_name;
 569         indio_dev->event_interface->group.attrs = kcalloc(attrcount + 1,
 570                                                           sizeof(indio_dev->event_interface->group.attrs[0]),
 571                                                           GFP_KERNEL);
 572         if (indio_dev->event_interface->group.attrs == NULL) {
 573                 ret = -ENOMEM;
 574                 goto error_free_setup_event_lines;
 575         }
 576         if (indio_dev->info->event_attrs)
 577                 memcpy(indio_dev->event_interface->group.attrs,
 578                        indio_dev->info->event_attrs->attrs,
 579                        sizeof(indio_dev->event_interface->group.attrs[0])
 580                        *attrcount_orig);
 581         attrn = attrcount_orig;
 582         /* Add all elements from the list. */
 583         list_for_each_entry(p,
 584                             &indio_dev->event_interface->dev_attr_list,
 585                             l)
 586                 indio_dev->event_interface->group.attrs[attrn++] =
 587                         &p->dev_attr.attr;
 588         indio_dev->groups[indio_dev->groupcounter++] =
 589                 &indio_dev->event_interface->group;
 590
 591         return 0;
 592
 593 error_free_setup_event_lines:
 594         iio_free_chan_devattr_list(&indio_dev->event_interface->dev_attr_list);
 595         kfree(indio_dev->event_interface);
 596 error_ret:
 597
 598         return ret;
 599 }
 600
 601 /**
 602  * iio_device_wakeup_eventset - Wakes up the event waitqueue
 603  * @indio_dev: The IIO device
 604  *
 605  * Wakes up the event waitqueue used for poll() and blocking read().
 606  * Should usually be called when the device is unregistered.
 607  */
 608 void iio_device_wakeup_eventset(struct iio_dev *indio_dev)
 609 {
 610         if (indio_dev->event_interface == NULL)
 611                 return;
 612         wake_up(&indio_dev->event_interface->wait);
 613 }
 614
 615 void iio_device_unregister_eventset(struct iio_dev *indio_dev)
 616 {
 617         if (indio_dev->event_interface == NULL)
 618                 return;
 619         iio_free_chan_devattr_list(&indio_dev->event_interface->dev_attr_list);
 620         kfree(indio_dev->event_interface->group.attrs);
 621         kfree(indio_dev->event_interface);
 622 }