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