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