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 */ 35 struct iio_event_interface { 36 wait_queue_head_t wait; 37 DECLARE_KFIFO(det_events, struct iio_event_data, 16); 38 39 struct list_head dev_attr_list; 40 unsigned long flags; 41 struct attribute_group group; 42 struct mutex read_lock; 43 }; 44 45 bool iio_event_enabled(const struct iio_event_interface *ev_int) 46 { 47 return !!test_bit(IIO_BUSY_BIT_POS, &ev_int->flags); 48 } 49 50 /** 51 * iio_push_event() - try to add event to the list for userspace reading 52 * @indio_dev: IIO device structure 53 * @ev_code: What event 54 * @timestamp: When the event occurred 55 * 56 * Note: The caller must make sure that this function is not running 57 * concurrently for the same indio_dev more than once. 58 * 59 * This function may be safely used as soon as a valid reference to iio_dev has 60 * been obtained via iio_device_alloc(), but any events that are submitted 61 * before iio_device_register() has successfully completed will be silently 62 * discarded. 63 **/ 64 int iio_push_event(struct iio_dev *indio_dev, u64 ev_code, s64 timestamp) 65 { 66 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev); 67 struct iio_event_interface *ev_int = iio_dev_opaque->event_interface; 68 struct iio_event_data ev; 69 int copied; 70 71 if (!ev_int) 72 return 0; 73 74 /* Does anyone care? */ 75 if (iio_event_enabled(ev_int)) { 76 77 ev.id = ev_code; 78 ev.timestamp = timestamp; 79 80 copied = kfifo_put(&ev_int->det_events, ev); 81 if (copied != 0) 82 wake_up_poll(&ev_int->wait, EPOLLIN); 83 } 84 85 return 0; 86 } 87 EXPORT_SYMBOL(iio_push_event); 88 89 /** 90 * iio_event_poll() - poll the event queue to find out if it has data 91 * @filep: File structure pointer to identify the device 92 * @wait: Poll table pointer to add the wait queue on 93 * 94 * Return: (EPOLLIN | EPOLLRDNORM) if data is available for reading 95 * or a negative error code on failure 96 */ 97 static __poll_t iio_event_poll(struct file *filep, 98 struct poll_table_struct *wait) 99 { 100 struct iio_dev *indio_dev = filep->private_data; 101 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev); 102 struct iio_event_interface *ev_int = iio_dev_opaque->event_interface; 103 __poll_t events = 0; 104 105 if (!indio_dev->info) 106 return events; 107 108 poll_wait(filep, &ev_int->wait, wait); 109 110 if (!kfifo_is_empty(&ev_int->det_events)) 111 events = EPOLLIN | EPOLLRDNORM; 112 113 return events; 114 } 115 116 static ssize_t iio_event_chrdev_read(struct file *filep, 117 char __user *buf, 118 size_t count, 119 loff_t *f_ps) 120 { 121 struct iio_dev *indio_dev = filep->private_data; 122 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev); 123 struct iio_event_interface *ev_int = iio_dev_opaque->event_interface; 124 unsigned int copied; 125 int ret; 126 127 if (!indio_dev->info) 128 return -ENODEV; 129 130 if (count < sizeof(struct iio_event_data)) 131 return -EINVAL; 132 133 do { 134 if (kfifo_is_empty(&ev_int->det_events)) { 135 if (filep->f_flags & O_NONBLOCK) 136 return -EAGAIN; 137 138 ret = wait_event_interruptible(ev_int->wait, 139 !kfifo_is_empty(&ev_int->det_events) || 140 indio_dev->info == NULL); 141 if (ret) 142 return ret; 143 if (indio_dev->info == NULL) 144 return -ENODEV; 145 } 146 147 if (mutex_lock_interruptible(&ev_int->read_lock)) 148 return -ERESTARTSYS; 149 ret = kfifo_to_user(&ev_int->det_events, buf, count, &copied); 150 mutex_unlock(&ev_int->read_lock); 151 152 if (ret) 153 return ret; 154 155 /* 156 * If we couldn't read anything from the fifo (a different 157 * thread might have been faster) we either return -EAGAIN if 158 * the file descriptor is non-blocking, otherwise we go back to 159 * sleep and wait for more data to arrive. 160 */ 161 if (copied == 0 && (filep->f_flags & O_NONBLOCK)) 162 return -EAGAIN; 163 164 } while (copied == 0); 165 166 return copied; 167 } 168 169 static int iio_event_chrdev_release(struct inode *inode, struct file *filep) 170 { 171 struct iio_dev *indio_dev = filep->private_data; 172 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev); 173 struct iio_event_interface *ev_int = iio_dev_opaque->event_interface; 174 175 clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags); 176 177 iio_device_put(indio_dev); 178 179 return 0; 180 } 181 182 static const struct file_operations iio_event_chrdev_fileops = { 183 .read = iio_event_chrdev_read, 184 .poll = iio_event_poll, 185 .release = iio_event_chrdev_release, 186 .owner = THIS_MODULE, 187 .llseek = noop_llseek, 188 }; 189 190 int iio_event_getfd(struct iio_dev *indio_dev) 191 { 192 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev); 193 struct iio_event_interface *ev_int = iio_dev_opaque->event_interface; 194 int fd; 195 196 if (ev_int == NULL) 197 return -ENODEV; 198 199 fd = mutex_lock_interruptible(&indio_dev->mlock); 200 if (fd) 201 return fd; 202 203 if (test_and_set_bit(IIO_BUSY_BIT_POS, &ev_int->flags)) { 204 fd = -EBUSY; 205 goto unlock; 206 } 207 208 iio_device_get(indio_dev); 209 210 fd = anon_inode_getfd("iio:event", &iio_event_chrdev_fileops, 211 indio_dev, O_RDONLY | O_CLOEXEC); 212 if (fd < 0) { 213 clear_bit(IIO_BUSY_BIT_POS, &ev_int->flags); 214 iio_device_put(indio_dev); 215 } else { 216 kfifo_reset_out(&ev_int->det_events); 217 } 218 219 unlock: 220 mutex_unlock(&indio_dev->mlock); 221 return fd; 222 } 223 224 static const char * const iio_ev_type_text[] = { 225 [IIO_EV_TYPE_THRESH] = "thresh", 226 [IIO_EV_TYPE_MAG] = "mag", 227 [IIO_EV_TYPE_ROC] = "roc", 228 [IIO_EV_TYPE_THRESH_ADAPTIVE] = "thresh_adaptive", 229 [IIO_EV_TYPE_MAG_ADAPTIVE] = "mag_adaptive", 230 [IIO_EV_TYPE_CHANGE] = "change", 231 }; 232 233 static const char * const iio_ev_dir_text[] = { 234 [IIO_EV_DIR_EITHER] = "either", 235 [IIO_EV_DIR_RISING] = "rising", 236 [IIO_EV_DIR_FALLING] = "falling" 237 }; 238 239 static const char * const iio_ev_info_text[] = { 240 [IIO_EV_INFO_ENABLE] = "en", 241 [IIO_EV_INFO_VALUE] = "value", 242 [IIO_EV_INFO_HYSTERESIS] = "hysteresis", 243 [IIO_EV_INFO_PERIOD] = "period", 244 [IIO_EV_INFO_HIGH_PASS_FILTER_3DB] = "high_pass_filter_3db", 245 [IIO_EV_INFO_LOW_PASS_FILTER_3DB] = "low_pass_filter_3db", 246 }; 247 248 static enum iio_event_direction iio_ev_attr_dir(struct iio_dev_attr *attr) 249 { 250 return attr->c->event_spec[attr->address & 0xffff].dir; 251 } 252 253 static enum iio_event_type iio_ev_attr_type(struct iio_dev_attr *attr) 254 { 255 return attr->c->event_spec[attr->address & 0xffff].type; 256 } 257 258 static enum iio_event_info iio_ev_attr_info(struct iio_dev_attr *attr) 259 { 260 return (attr->address >> 16) & 0xffff; 261 } 262 263 static ssize_t iio_ev_state_store(struct device *dev, 264 struct device_attribute *attr, 265 const char *buf, 266 size_t len) 267 { 268 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 269 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr); 270 int ret; 271 bool val; 272 273 ret = strtobool(buf, &val); 274 if (ret < 0) 275 return ret; 276 277 ret = indio_dev->info->write_event_config(indio_dev, 278 this_attr->c, iio_ev_attr_type(this_attr), 279 iio_ev_attr_dir(this_attr), val); 280 281 return (ret < 0) ? ret : len; 282 } 283 284 static ssize_t iio_ev_state_show(struct device *dev, 285 struct device_attribute *attr, 286 char *buf) 287 { 288 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 289 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr); 290 int val; 291 292 val = indio_dev->info->read_event_config(indio_dev, 293 this_attr->c, iio_ev_attr_type(this_attr), 294 iio_ev_attr_dir(this_attr)); 295 if (val < 0) 296 return val; 297 else 298 return sprintf(buf, "%d\n", val); 299 } 300 301 static ssize_t iio_ev_value_show(struct device *dev, 302 struct device_attribute *attr, 303 char *buf) 304 { 305 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 306 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr); 307 int val, val2, val_arr[2]; 308 int ret; 309 310 ret = indio_dev->info->read_event_value(indio_dev, 311 this_attr->c, iio_ev_attr_type(this_attr), 312 iio_ev_attr_dir(this_attr), iio_ev_attr_info(this_attr), 313 &val, &val2); 314 if (ret < 0) 315 return ret; 316 val_arr[0] = val; 317 val_arr[1] = val2; 318 return iio_format_value(buf, ret, 2, val_arr); 319 } 320 321 static ssize_t iio_ev_value_store(struct device *dev, 322 struct device_attribute *attr, 323 const char *buf, 324 size_t len) 325 { 326 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 327 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr); 328 int val, val2; 329 int ret; 330 331 if (!indio_dev->info->write_event_value) 332 return -EINVAL; 333 334 ret = iio_str_to_fixpoint(buf, 100000, &val, &val2); 335 if (ret) 336 return ret; 337 ret = indio_dev->info->write_event_value(indio_dev, 338 this_attr->c, iio_ev_attr_type(this_attr), 339 iio_ev_attr_dir(this_attr), iio_ev_attr_info(this_attr), 340 val, val2); 341 if (ret < 0) 342 return ret; 343 344 return len; 345 } 346 347 static int iio_device_add_event(struct iio_dev *indio_dev, 348 const struct iio_chan_spec *chan, unsigned int spec_index, 349 enum iio_event_type type, enum iio_event_direction dir, 350 enum iio_shared_by shared_by, const unsigned long *mask) 351 { 352 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev); 353 ssize_t (*show)(struct device *, struct device_attribute *, char *); 354 ssize_t (*store)(struct device *, struct device_attribute *, 355 const char *, size_t); 356 unsigned int attrcount = 0; 357 unsigned int i; 358 char *postfix; 359 int ret; 360 361 for_each_set_bit(i, mask, sizeof(*mask)*8) { 362 if (i >= ARRAY_SIZE(iio_ev_info_text)) 363 return -EINVAL; 364 if (dir != IIO_EV_DIR_NONE) 365 postfix = kasprintf(GFP_KERNEL, "%s_%s_%s", 366 iio_ev_type_text[type], 367 iio_ev_dir_text[dir], 368 iio_ev_info_text[i]); 369 else 370 postfix = kasprintf(GFP_KERNEL, "%s_%s", 371 iio_ev_type_text[type], 372 iio_ev_info_text[i]); 373 if (postfix == NULL) 374 return -ENOMEM; 375 376 if (i == IIO_EV_INFO_ENABLE) { 377 show = iio_ev_state_show; 378 store = iio_ev_state_store; 379 } else { 380 show = iio_ev_value_show; 381 store = iio_ev_value_store; 382 } 383 384 ret = __iio_add_chan_devattr(postfix, chan, show, store, 385 (i << 16) | spec_index, shared_by, &indio_dev->dev, 386 &iio_dev_opaque->event_interface->dev_attr_list); 387 kfree(postfix); 388 389 if ((ret == -EBUSY) && (shared_by != IIO_SEPARATE)) 390 continue; 391 392 if (ret) 393 return ret; 394 395 attrcount++; 396 } 397 398 return attrcount; 399 } 400 401 static int iio_device_add_event_sysfs(struct iio_dev *indio_dev, 402 struct iio_chan_spec const *chan) 403 { 404 int ret = 0, i, attrcount = 0; 405 enum iio_event_direction dir; 406 enum iio_event_type type; 407 408 for (i = 0; i < chan->num_event_specs; i++) { 409 type = chan->event_spec[i].type; 410 dir = chan->event_spec[i].dir; 411 412 ret = iio_device_add_event(indio_dev, chan, i, type, dir, 413 IIO_SEPARATE, &chan->event_spec[i].mask_separate); 414 if (ret < 0) 415 return ret; 416 attrcount += ret; 417 418 ret = iio_device_add_event(indio_dev, chan, i, type, dir, 419 IIO_SHARED_BY_TYPE, 420 &chan->event_spec[i].mask_shared_by_type); 421 if (ret < 0) 422 return ret; 423 attrcount += ret; 424 425 ret = iio_device_add_event(indio_dev, chan, i, type, dir, 426 IIO_SHARED_BY_DIR, 427 &chan->event_spec[i].mask_shared_by_dir); 428 if (ret < 0) 429 return ret; 430 attrcount += ret; 431 432 ret = iio_device_add_event(indio_dev, chan, i, type, dir, 433 IIO_SHARED_BY_ALL, 434 &chan->event_spec[i].mask_shared_by_all); 435 if (ret < 0) 436 return ret; 437 attrcount += ret; 438 } 439 ret = attrcount; 440 return ret; 441 } 442 443 static inline int __iio_add_event_config_attrs(struct iio_dev *indio_dev) 444 { 445 int j, ret, attrcount = 0; 446 447 /* Dynamically created from the channels array */ 448 for (j = 0; j < indio_dev->num_channels; j++) { 449 ret = iio_device_add_event_sysfs(indio_dev, 450 &indio_dev->channels[j]); 451 if (ret < 0) 452 return ret; 453 attrcount += ret; 454 } 455 return attrcount; 456 } 457 458 static bool iio_check_for_dynamic_events(struct iio_dev *indio_dev) 459 { 460 int j; 461 462 for (j = 0; j < indio_dev->num_channels; j++) { 463 if (indio_dev->channels[j].num_event_specs != 0) 464 return true; 465 } 466 return false; 467 } 468 469 static void iio_setup_ev_int(struct iio_event_interface *ev_int) 470 { 471 INIT_KFIFO(ev_int->det_events); 472 init_waitqueue_head(&ev_int->wait); 473 mutex_init(&ev_int->read_lock); 474 } 475 476 static const char *iio_event_group_name = "events"; 477 int iio_device_register_eventset(struct iio_dev *indio_dev) 478 { 479 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev); 480 struct iio_dev_attr *p; 481 int ret = 0, attrcount_orig = 0, attrcount, attrn; 482 struct attribute **attr; 483 484 if (!(indio_dev->info->event_attrs || 485 iio_check_for_dynamic_events(indio_dev))) 486 return 0; 487 488 iio_dev_opaque->event_interface = 489 kzalloc(sizeof(struct iio_event_interface), GFP_KERNEL); 490 if (iio_dev_opaque->event_interface == NULL) 491 return -ENOMEM; 492 493 INIT_LIST_HEAD(&iio_dev_opaque->event_interface->dev_attr_list); 494 495 iio_setup_ev_int(iio_dev_opaque->event_interface); 496 if (indio_dev->info->event_attrs != NULL) { 497 attr = indio_dev->info->event_attrs->attrs; 498 while (*attr++ != NULL) 499 attrcount_orig++; 500 } 501 attrcount = attrcount_orig; 502 if (indio_dev->channels) { 503 ret = __iio_add_event_config_attrs(indio_dev); 504 if (ret < 0) 505 goto error_free_setup_event_lines; 506 attrcount += ret; 507 } 508 509 iio_dev_opaque->event_interface->group.name = iio_event_group_name; 510 iio_dev_opaque->event_interface->group.attrs = kcalloc(attrcount + 1, 511 sizeof(iio_dev_opaque->event_interface->group.attrs[0]), 512 GFP_KERNEL); 513 if (iio_dev_opaque->event_interface->group.attrs == NULL) { 514 ret = -ENOMEM; 515 goto error_free_setup_event_lines; 516 } 517 if (indio_dev->info->event_attrs) 518 memcpy(iio_dev_opaque->event_interface->group.attrs, 519 indio_dev->info->event_attrs->attrs, 520 sizeof(iio_dev_opaque->event_interface->group.attrs[0]) 521 *attrcount_orig); 522 attrn = attrcount_orig; 523 /* Add all elements from the list. */ 524 list_for_each_entry(p, 525 &iio_dev_opaque->event_interface->dev_attr_list, 526 l) 527 iio_dev_opaque->event_interface->group.attrs[attrn++] = 528 &p->dev_attr.attr; 529 indio_dev->groups[indio_dev->groupcounter++] = 530 &iio_dev_opaque->event_interface->group; 531 532 return 0; 533 534 error_free_setup_event_lines: 535 iio_free_chan_devattr_list(&iio_dev_opaque->event_interface->dev_attr_list); 536 kfree(iio_dev_opaque->event_interface); 537 iio_dev_opaque->event_interface = NULL; 538 return ret; 539 } 540 541 /** 542 * iio_device_wakeup_eventset - Wakes up the event waitqueue 543 * @indio_dev: The IIO device 544 * 545 * Wakes up the event waitqueue used for poll() and blocking read(). 546 * Should usually be called when the device is unregistered. 547 */ 548 void iio_device_wakeup_eventset(struct iio_dev *indio_dev) 549 { 550 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev); 551 552 if (iio_dev_opaque->event_interface == NULL) 553 return; 554 wake_up(&iio_dev_opaque->event_interface->wait); 555 } 556 557 void iio_device_unregister_eventset(struct iio_dev *indio_dev) 558 { 559 struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev); 560 561 if (iio_dev_opaque->event_interface == NULL) 562 return; 563 iio_free_chan_devattr_list(&iio_dev_opaque->event_interface->dev_attr_list); 564 kfree(iio_dev_opaque->event_interface->group.attrs); 565 kfree(iio_dev_opaque->event_interface); 566 } 567