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(&indio_dev->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(&indio_dev->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 }; 234 235 static const char * const iio_ev_dir_text[] = { 236 [IIO_EV_DIR_EITHER] = "either", 237 [IIO_EV_DIR_RISING] = "rising", 238 [IIO_EV_DIR_FALLING] = "falling" 239 }; 240 241 static const char * const iio_ev_info_text[] = { 242 [IIO_EV_INFO_ENABLE] = "en", 243 [IIO_EV_INFO_VALUE] = "value", 244 [IIO_EV_INFO_HYSTERESIS] = "hysteresis", 245 [IIO_EV_INFO_PERIOD] = "period", 246 [IIO_EV_INFO_HIGH_PASS_FILTER_3DB] = "high_pass_filter_3db", 247 [IIO_EV_INFO_LOW_PASS_FILTER_3DB] = "low_pass_filter_3db", 248 }; 249 250 static enum iio_event_direction iio_ev_attr_dir(struct iio_dev_attr *attr) 251 { 252 return attr->c->event_spec[attr->address & 0xffff].dir; 253 } 254 255 static enum iio_event_type iio_ev_attr_type(struct iio_dev_attr *attr) 256 { 257 return attr->c->event_spec[attr->address & 0xffff].type; 258 } 259 260 static enum iio_event_info iio_ev_attr_info(struct iio_dev_attr *attr) 261 { 262 return (attr->address >> 16) & 0xffff; 263 } 264 265 static ssize_t iio_ev_state_store(struct device *dev, 266 struct device_attribute *attr, 267 const char *buf, 268 size_t len) 269 { 270 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 271 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr); 272 int ret; 273 bool val; 274 275 ret = strtobool(buf, &val); 276 if (ret < 0) 277 return ret; 278 279 ret = indio_dev->info->write_event_config(indio_dev, 280 this_attr->c, iio_ev_attr_type(this_attr), 281 iio_ev_attr_dir(this_attr), val); 282 283 return (ret < 0) ? ret : len; 284 } 285 286 static ssize_t iio_ev_state_show(struct device *dev, 287 struct device_attribute *attr, 288 char *buf) 289 { 290 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 291 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr); 292 int val; 293 294 val = indio_dev->info->read_event_config(indio_dev, 295 this_attr->c, iio_ev_attr_type(this_attr), 296 iio_ev_attr_dir(this_attr)); 297 if (val < 0) 298 return val; 299 else 300 return sprintf(buf, "%d\n", val); 301 } 302 303 static ssize_t iio_ev_value_show(struct device *dev, 304 struct device_attribute *attr, 305 char *buf) 306 { 307 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 308 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr); 309 int val, val2, val_arr[2]; 310 int ret; 311 312 ret = indio_dev->info->read_event_value(indio_dev, 313 this_attr->c, iio_ev_attr_type(this_attr), 314 iio_ev_attr_dir(this_attr), iio_ev_attr_info(this_attr), 315 &val, &val2); 316 if (ret < 0) 317 return ret; 318 val_arr[0] = val; 319 val_arr[1] = val2; 320 return iio_format_value(buf, ret, 2, val_arr); 321 } 322 323 static ssize_t iio_ev_value_store(struct device *dev, 324 struct device_attribute *attr, 325 const char *buf, 326 size_t len) 327 { 328 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 329 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr); 330 int val, val2; 331 int ret; 332 333 if (!indio_dev->info->write_event_value) 334 return -EINVAL; 335 336 ret = iio_str_to_fixpoint(buf, 100000, &val, &val2); 337 if (ret) 338 return ret; 339 ret = indio_dev->info->write_event_value(indio_dev, 340 this_attr->c, iio_ev_attr_type(this_attr), 341 iio_ev_attr_dir(this_attr), iio_ev_attr_info(this_attr), 342 val, val2); 343 if (ret < 0) 344 return ret; 345 346 return len; 347 } 348 349 static int iio_device_add_event(struct iio_dev *indio_dev, 350 const struct iio_chan_spec *chan, unsigned int spec_index, 351 enum iio_event_type type, enum iio_event_direction dir, 352 enum iio_shared_by shared_by, const unsigned long *mask) 353 { 354 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev); 355 ssize_t (*show)(struct device *, struct device_attribute *, char *); 356 ssize_t (*store)(struct device *, struct device_attribute *, 357 const char *, size_t); 358 unsigned int attrcount = 0; 359 unsigned int i; 360 char *postfix; 361 int ret; 362 363 for_each_set_bit(i, mask, sizeof(*mask)*8) { 364 if (i >= ARRAY_SIZE(iio_ev_info_text)) 365 return -EINVAL; 366 if (dir != IIO_EV_DIR_NONE) 367 postfix = kasprintf(GFP_KERNEL, "%s_%s_%s", 368 iio_ev_type_text[type], 369 iio_ev_dir_text[dir], 370 iio_ev_info_text[i]); 371 else 372 postfix = kasprintf(GFP_KERNEL, "%s_%s", 373 iio_ev_type_text[type], 374 iio_ev_info_text[i]); 375 if (postfix == NULL) 376 return -ENOMEM; 377 378 if (i == IIO_EV_INFO_ENABLE) { 379 show = iio_ev_state_show; 380 store = iio_ev_state_store; 381 } else { 382 show = iio_ev_value_show; 383 store = iio_ev_value_store; 384 } 385 386 ret = __iio_add_chan_devattr(postfix, chan, show, store, 387 (i << 16) | spec_index, shared_by, &indio_dev->dev, 388 &iio_dev_opaque->event_interface->dev_attr_list); 389 kfree(postfix); 390 391 if ((ret == -EBUSY) && (shared_by != IIO_SEPARATE)) 392 continue; 393 394 if (ret) 395 return ret; 396 397 attrcount++; 398 } 399 400 return attrcount; 401 } 402 403 static int iio_device_add_event_sysfs(struct iio_dev *indio_dev, 404 struct iio_chan_spec const *chan) 405 { 406 int ret = 0, i, attrcount = 0; 407 enum iio_event_direction dir; 408 enum iio_event_type type; 409 410 for (i = 0; i < chan->num_event_specs; i++) { 411 type = chan->event_spec[i].type; 412 dir = chan->event_spec[i].dir; 413 414 ret = iio_device_add_event(indio_dev, chan, i, type, dir, 415 IIO_SEPARATE, &chan->event_spec[i].mask_separate); 416 if (ret < 0) 417 return ret; 418 attrcount += ret; 419 420 ret = iio_device_add_event(indio_dev, chan, i, type, dir, 421 IIO_SHARED_BY_TYPE, 422 &chan->event_spec[i].mask_shared_by_type); 423 if (ret < 0) 424 return ret; 425 attrcount += ret; 426 427 ret = iio_device_add_event(indio_dev, chan, i, type, dir, 428 IIO_SHARED_BY_DIR, 429 &chan->event_spec[i].mask_shared_by_dir); 430 if (ret < 0) 431 return ret; 432 attrcount += ret; 433 434 ret = iio_device_add_event(indio_dev, chan, i, type, dir, 435 IIO_SHARED_BY_ALL, 436 &chan->event_spec[i].mask_shared_by_all); 437 if (ret < 0) 438 return ret; 439 attrcount += ret; 440 } 441 ret = attrcount; 442 return ret; 443 } 444 445 static inline int __iio_add_event_config_attrs(struct iio_dev *indio_dev) 446 { 447 int j, ret, attrcount = 0; 448 449 /* Dynamically created from the channels array */ 450 for (j = 0; j < indio_dev->num_channels; j++) { 451 ret = iio_device_add_event_sysfs(indio_dev, 452 &indio_dev->channels[j]); 453 if (ret < 0) 454 return ret; 455 attrcount += ret; 456 } 457 return attrcount; 458 } 459 460 static bool iio_check_for_dynamic_events(struct iio_dev *indio_dev) 461 { 462 int j; 463 464 for (j = 0; j < indio_dev->num_channels; j++) { 465 if (indio_dev->channels[j].num_event_specs != 0) 466 return true; 467 } 468 return false; 469 } 470 471 static void iio_setup_ev_int(struct iio_event_interface *ev_int) 472 { 473 INIT_KFIFO(ev_int->det_events); 474 init_waitqueue_head(&ev_int->wait); 475 mutex_init(&ev_int->read_lock); 476 } 477 478 static long iio_event_ioctl(struct iio_dev *indio_dev, struct file *filp, 479 unsigned int cmd, unsigned long arg) 480 { 481 int __user *ip = (int __user *)arg; 482 int fd; 483 484 if (cmd == IIO_GET_EVENT_FD_IOCTL) { 485 fd = iio_event_getfd(indio_dev); 486 if (fd < 0) 487 return fd; 488 if (copy_to_user(ip, &fd, sizeof(fd))) 489 return -EFAULT; 490 return 0; 491 } 492 493 return IIO_IOCTL_UNHANDLED; 494 } 495 496 static const char *iio_event_group_name = "events"; 497 int iio_device_register_eventset(struct iio_dev *indio_dev) 498 { 499 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev); 500 struct iio_event_interface *ev_int; 501 struct iio_dev_attr *p; 502 int ret = 0, attrcount_orig = 0, attrcount, attrn; 503 struct attribute **attr; 504 505 if (!(indio_dev->info->event_attrs || 506 iio_check_for_dynamic_events(indio_dev))) 507 return 0; 508 509 ev_int = kzalloc(sizeof(struct iio_event_interface), GFP_KERNEL); 510 if (ev_int == NULL) 511 return -ENOMEM; 512 513 iio_dev_opaque->event_interface = ev_int; 514 515 INIT_LIST_HEAD(&ev_int->dev_attr_list); 516 517 iio_setup_ev_int(ev_int); 518 if (indio_dev->info->event_attrs != NULL) { 519 attr = indio_dev->info->event_attrs->attrs; 520 while (*attr++ != NULL) 521 attrcount_orig++; 522 } 523 attrcount = attrcount_orig; 524 if (indio_dev->channels) { 525 ret = __iio_add_event_config_attrs(indio_dev); 526 if (ret < 0) 527 goto error_free_setup_event_lines; 528 attrcount += ret; 529 } 530 531 ev_int->group.name = iio_event_group_name; 532 ev_int->group.attrs = kcalloc(attrcount + 1, 533 sizeof(ev_int->group.attrs[0]), 534 GFP_KERNEL); 535 if (ev_int->group.attrs == NULL) { 536 ret = -ENOMEM; 537 goto error_free_setup_event_lines; 538 } 539 if (indio_dev->info->event_attrs) 540 memcpy(ev_int->group.attrs, 541 indio_dev->info->event_attrs->attrs, 542 sizeof(ev_int->group.attrs[0]) * attrcount_orig); 543 attrn = attrcount_orig; 544 /* Add all elements from the list. */ 545 list_for_each_entry(p, &ev_int->dev_attr_list, l) 546 ev_int->group.attrs[attrn++] = &p->dev_attr.attr; 547 indio_dev->groups[indio_dev->groupcounter++] = &ev_int->group; 548 549 ev_int->ioctl_handler.ioctl = iio_event_ioctl; 550 iio_device_ioctl_handler_register(&iio_dev_opaque->indio_dev, 551 &ev_int->ioctl_handler); 552 553 return 0; 554 555 error_free_setup_event_lines: 556 iio_free_chan_devattr_list(&ev_int->dev_attr_list); 557 kfree(ev_int); 558 iio_dev_opaque->event_interface = NULL; 559 return ret; 560 } 561 562 /** 563 * iio_device_wakeup_eventset - Wakes up the event waitqueue 564 * @indio_dev: The IIO device 565 * 566 * Wakes up the event waitqueue used for poll() and blocking read(). 567 * Should usually be called when the device is unregistered. 568 */ 569 void iio_device_wakeup_eventset(struct iio_dev *indio_dev) 570 { 571 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev); 572 573 if (iio_dev_opaque->event_interface == NULL) 574 return; 575 wake_up(&iio_dev_opaque->event_interface->wait); 576 } 577 578 void iio_device_unregister_eventset(struct iio_dev *indio_dev) 579 { 580 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev); 581 struct iio_event_interface *ev_int = iio_dev_opaque->event_interface; 582 583 if (ev_int == NULL) 584 return; 585 586 iio_device_ioctl_handler_unregister(&ev_int->ioctl_handler); 587 iio_free_chan_devattr_list(&ev_int->dev_attr_list); 588 kfree(ev_int->group.attrs); 589 kfree(ev_int); 590 iio_dev_opaque->event_interface = NULL; 591 } 592