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 ret = indio_dev->info->write_event_config(indio_dev, 289 this_attr->c, iio_ev_attr_type(this_attr), 290 iio_ev_attr_dir(this_attr), val); 291 292 return (ret < 0) ? ret : len; 293 } 294 295 static ssize_t iio_ev_state_show(struct device *dev, 296 struct device_attribute *attr, 297 char *buf) 298 { 299 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 300 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr); 301 int val; 302 303 val = indio_dev->info->read_event_config(indio_dev, 304 this_attr->c, iio_ev_attr_type(this_attr), 305 iio_ev_attr_dir(this_attr)); 306 if (val < 0) 307 return val; 308 else 309 return sysfs_emit(buf, "%d\n", val); 310 } 311 312 static ssize_t iio_ev_value_show(struct device *dev, 313 struct device_attribute *attr, 314 char *buf) 315 { 316 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 317 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr); 318 int val, val2, val_arr[2]; 319 int ret; 320 321 ret = indio_dev->info->read_event_value(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 if (ret < 0) 326 return ret; 327 val_arr[0] = val; 328 val_arr[1] = val2; 329 return iio_format_value(buf, ret, 2, val_arr); 330 } 331 332 static ssize_t iio_ev_value_store(struct device *dev, 333 struct device_attribute *attr, 334 const char *buf, 335 size_t len) 336 { 337 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 338 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr); 339 int val, val2; 340 int ret; 341 342 if (!indio_dev->info->write_event_value) 343 return -EINVAL; 344 345 ret = iio_str_to_fixpoint(buf, 100000, &val, &val2); 346 if (ret) 347 return ret; 348 ret = indio_dev->info->write_event_value(indio_dev, 349 this_attr->c, iio_ev_attr_type(this_attr), 350 iio_ev_attr_dir(this_attr), iio_ev_attr_info(this_attr), 351 val, val2); 352 if (ret < 0) 353 return ret; 354 355 return len; 356 } 357 358 static int iio_device_add_event(struct iio_dev *indio_dev, 359 const struct iio_chan_spec *chan, unsigned int spec_index, 360 enum iio_event_type type, enum iio_event_direction dir, 361 enum iio_shared_by shared_by, const unsigned long *mask) 362 { 363 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev); 364 ssize_t (*show)(struct device *dev, struct device_attribute *attr, 365 char *buf); 366 ssize_t (*store)(struct device *dev, struct device_attribute *attr, 367 const char *buf, size_t len); 368 unsigned int attrcount = 0; 369 unsigned int i; 370 char *postfix; 371 int ret; 372 373 for_each_set_bit(i, mask, sizeof(*mask)*8) { 374 if (i >= ARRAY_SIZE(iio_ev_info_text)) 375 return -EINVAL; 376 if (dir != IIO_EV_DIR_NONE) 377 postfix = kasprintf(GFP_KERNEL, "%s_%s_%s", 378 iio_ev_type_text[type], 379 iio_ev_dir_text[dir], 380 iio_ev_info_text[i]); 381 else 382 postfix = kasprintf(GFP_KERNEL, "%s_%s", 383 iio_ev_type_text[type], 384 iio_ev_info_text[i]); 385 if (postfix == NULL) 386 return -ENOMEM; 387 388 if (i == IIO_EV_INFO_ENABLE) { 389 show = iio_ev_state_show; 390 store = iio_ev_state_store; 391 } else { 392 show = iio_ev_value_show; 393 store = iio_ev_value_store; 394 } 395 396 ret = __iio_add_chan_devattr(postfix, chan, show, store, 397 (i << 16) | spec_index, shared_by, &indio_dev->dev, 398 NULL, 399 &iio_dev_opaque->event_interface->dev_attr_list); 400 kfree(postfix); 401 402 if ((ret == -EBUSY) && (shared_by != IIO_SEPARATE)) 403 continue; 404 405 if (ret) 406 return ret; 407 408 attrcount++; 409 } 410 411 return attrcount; 412 } 413 414 static int iio_device_add_event_sysfs(struct iio_dev *indio_dev, 415 struct iio_chan_spec const *chan) 416 { 417 int ret = 0, i, attrcount = 0; 418 enum iio_event_direction dir; 419 enum iio_event_type type; 420 421 for (i = 0; i < chan->num_event_specs; i++) { 422 type = chan->event_spec[i].type; 423 dir = chan->event_spec[i].dir; 424 425 ret = iio_device_add_event(indio_dev, chan, i, type, dir, 426 IIO_SEPARATE, &chan->event_spec[i].mask_separate); 427 if (ret < 0) 428 return ret; 429 attrcount += ret; 430 431 ret = iio_device_add_event(indio_dev, chan, i, type, dir, 432 IIO_SHARED_BY_TYPE, 433 &chan->event_spec[i].mask_shared_by_type); 434 if (ret < 0) 435 return ret; 436 attrcount += ret; 437 438 ret = iio_device_add_event(indio_dev, chan, i, type, dir, 439 IIO_SHARED_BY_DIR, 440 &chan->event_spec[i].mask_shared_by_dir); 441 if (ret < 0) 442 return ret; 443 attrcount += ret; 444 445 ret = iio_device_add_event(indio_dev, chan, i, type, dir, 446 IIO_SHARED_BY_ALL, 447 &chan->event_spec[i].mask_shared_by_all); 448 if (ret < 0) 449 return ret; 450 attrcount += ret; 451 } 452 ret = attrcount; 453 return ret; 454 } 455 456 static inline int __iio_add_event_config_attrs(struct iio_dev *indio_dev) 457 { 458 int j, ret, attrcount = 0; 459 460 /* Dynamically created from the channels array */ 461 for (j = 0; j < indio_dev->num_channels; j++) { 462 ret = iio_device_add_event_sysfs(indio_dev, 463 &indio_dev->channels[j]); 464 if (ret < 0) 465 return ret; 466 attrcount += ret; 467 } 468 return attrcount; 469 } 470 471 static bool iio_check_for_dynamic_events(struct iio_dev *indio_dev) 472 { 473 int j; 474 475 for (j = 0; j < indio_dev->num_channels; j++) { 476 if (indio_dev->channels[j].num_event_specs != 0) 477 return true; 478 } 479 return false; 480 } 481 482 static void iio_setup_ev_int(struct iio_event_interface *ev_int) 483 { 484 INIT_KFIFO(ev_int->det_events); 485 init_waitqueue_head(&ev_int->wait); 486 mutex_init(&ev_int->read_lock); 487 } 488 489 static long iio_event_ioctl(struct iio_dev *indio_dev, struct file *filp, 490 unsigned int cmd, unsigned long arg) 491 { 492 int __user *ip = (int __user *)arg; 493 int fd; 494 495 if (cmd == IIO_GET_EVENT_FD_IOCTL) { 496 fd = iio_event_getfd(indio_dev); 497 if (fd < 0) 498 return fd; 499 if (copy_to_user(ip, &fd, sizeof(fd))) 500 return -EFAULT; 501 return 0; 502 } 503 504 return IIO_IOCTL_UNHANDLED; 505 } 506 507 static const char *iio_event_group_name = "events"; 508 int iio_device_register_eventset(struct iio_dev *indio_dev) 509 { 510 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev); 511 struct iio_event_interface *ev_int; 512 struct iio_dev_attr *p; 513 int ret = 0, attrcount_orig = 0, attrcount, attrn; 514 struct attribute **attr; 515 516 if (!(indio_dev->info->event_attrs || 517 iio_check_for_dynamic_events(indio_dev))) 518 return 0; 519 520 ev_int = kzalloc(sizeof(struct iio_event_interface), GFP_KERNEL); 521 if (ev_int == NULL) 522 return -ENOMEM; 523 524 iio_dev_opaque->event_interface = ev_int; 525 526 INIT_LIST_HEAD(&ev_int->dev_attr_list); 527 528 iio_setup_ev_int(ev_int); 529 if (indio_dev->info->event_attrs != NULL) { 530 attr = indio_dev->info->event_attrs->attrs; 531 while (*attr++ != NULL) 532 attrcount_orig++; 533 } 534 attrcount = attrcount_orig; 535 if (indio_dev->channels) { 536 ret = __iio_add_event_config_attrs(indio_dev); 537 if (ret < 0) 538 goto error_free_setup_event_lines; 539 attrcount += ret; 540 } 541 542 ev_int->group.name = iio_event_group_name; 543 ev_int->group.attrs = kcalloc(attrcount + 1, 544 sizeof(ev_int->group.attrs[0]), 545 GFP_KERNEL); 546 if (ev_int->group.attrs == NULL) { 547 ret = -ENOMEM; 548 goto error_free_setup_event_lines; 549 } 550 if (indio_dev->info->event_attrs) 551 memcpy(ev_int->group.attrs, 552 indio_dev->info->event_attrs->attrs, 553 sizeof(ev_int->group.attrs[0]) * attrcount_orig); 554 attrn = attrcount_orig; 555 /* Add all elements from the list. */ 556 list_for_each_entry(p, &ev_int->dev_attr_list, l) 557 ev_int->group.attrs[attrn++] = &p->dev_attr.attr; 558 559 ret = iio_device_register_sysfs_group(indio_dev, &ev_int->group); 560 if (ret) 561 goto error_free_group_attrs; 562 563 ev_int->ioctl_handler.ioctl = iio_event_ioctl; 564 iio_device_ioctl_handler_register(&iio_dev_opaque->indio_dev, 565 &ev_int->ioctl_handler); 566 567 return 0; 568 569 error_free_group_attrs: 570 kfree(ev_int->group.attrs); 571 error_free_setup_event_lines: 572 iio_free_chan_devattr_list(&ev_int->dev_attr_list); 573 kfree(ev_int); 574 iio_dev_opaque->event_interface = NULL; 575 return ret; 576 } 577 578 /** 579 * iio_device_wakeup_eventset - Wakes up the event waitqueue 580 * @indio_dev: The IIO device 581 * 582 * Wakes up the event waitqueue used for poll() and blocking read(). 583 * Should usually be called when the device is unregistered. 584 */ 585 void iio_device_wakeup_eventset(struct iio_dev *indio_dev) 586 { 587 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev); 588 589 if (iio_dev_opaque->event_interface == NULL) 590 return; 591 wake_up(&iio_dev_opaque->event_interface->wait); 592 } 593 594 void iio_device_unregister_eventset(struct iio_dev *indio_dev) 595 { 596 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev); 597 struct iio_event_interface *ev_int = iio_dev_opaque->event_interface; 598 599 if (ev_int == NULL) 600 return; 601 602 iio_device_ioctl_handler_unregister(&ev_int->ioctl_handler); 603 iio_free_chan_devattr_list(&ev_int->dev_attr_list); 604 kfree(ev_int->group.attrs); 605 kfree(ev_int); 606 iio_dev_opaque->event_interface = NULL; 607 } 608