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 }; 215 216 static enum iio_event_direction iio_ev_attr_dir(struct iio_dev_attr *attr) 217 { 218 return attr->c->event_spec[attr->address & 0xffff].dir; 219 } 220 221 static enum iio_event_type iio_ev_attr_type(struct iio_dev_attr *attr) 222 { 223 return attr->c->event_spec[attr->address & 0xffff].type; 224 } 225 226 static enum iio_event_info iio_ev_attr_info(struct iio_dev_attr *attr) 227 { 228 return (attr->address >> 16) & 0xffff; 229 } 230 231 static ssize_t iio_ev_state_store(struct device *dev, 232 struct device_attribute *attr, 233 const char *buf, 234 size_t len) 235 { 236 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 237 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr); 238 int ret; 239 bool val; 240 241 ret = strtobool(buf, &val); 242 if (ret < 0) 243 return ret; 244 245 ret = indio_dev->info->write_event_config(indio_dev, 246 this_attr->c, iio_ev_attr_type(this_attr), 247 iio_ev_attr_dir(this_attr), val); 248 249 return (ret < 0) ? ret : len; 250 } 251 252 static ssize_t iio_ev_state_show(struct device *dev, 253 struct device_attribute *attr, 254 char *buf) 255 { 256 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 257 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr); 258 int val; 259 260 val = indio_dev->info->read_event_config(indio_dev, 261 this_attr->c, iio_ev_attr_type(this_attr), 262 iio_ev_attr_dir(this_attr)); 263 if (val < 0) 264 return val; 265 else 266 return sprintf(buf, "%d\n", val); 267 } 268 269 static ssize_t iio_ev_value_show(struct device *dev, 270 struct device_attribute *attr, 271 char *buf) 272 { 273 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 274 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr); 275 int val, val2, val_arr[2]; 276 int ret; 277 278 ret = indio_dev->info->read_event_value(indio_dev, 279 this_attr->c, iio_ev_attr_type(this_attr), 280 iio_ev_attr_dir(this_attr), iio_ev_attr_info(this_attr), 281 &val, &val2); 282 if (ret < 0) 283 return ret; 284 val_arr[0] = val; 285 val_arr[1] = val2; 286 return iio_format_value(buf, ret, 2, val_arr); 287 } 288 289 static ssize_t iio_ev_value_store(struct device *dev, 290 struct device_attribute *attr, 291 const char *buf, 292 size_t len) 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; 297 int ret; 298 299 if (!indio_dev->info->write_event_value) 300 return -EINVAL; 301 302 ret = iio_str_to_fixpoint(buf, 100000, &val, &val2); 303 if (ret) 304 return ret; 305 ret = indio_dev->info->write_event_value(indio_dev, 306 this_attr->c, iio_ev_attr_type(this_attr), 307 iio_ev_attr_dir(this_attr), iio_ev_attr_info(this_attr), 308 val, val2); 309 if (ret < 0) 310 return ret; 311 312 return len; 313 } 314 315 static int iio_device_add_event(struct iio_dev *indio_dev, 316 const struct iio_chan_spec *chan, unsigned int spec_index, 317 enum iio_event_type type, enum iio_event_direction dir, 318 enum iio_shared_by shared_by, const unsigned long *mask) 319 { 320 ssize_t (*show)(struct device *, struct device_attribute *, char *); 321 ssize_t (*store)(struct device *, struct device_attribute *, 322 const char *, size_t); 323 unsigned int attrcount = 0; 324 unsigned int i; 325 char *postfix; 326 int ret; 327 328 for_each_set_bit(i, mask, sizeof(*mask)*8) { 329 if (i >= ARRAY_SIZE(iio_ev_info_text)) 330 return -EINVAL; 331 if (dir != IIO_EV_DIR_NONE) 332 postfix = kasprintf(GFP_KERNEL, "%s_%s_%s", 333 iio_ev_type_text[type], 334 iio_ev_dir_text[dir], 335 iio_ev_info_text[i]); 336 else 337 postfix = kasprintf(GFP_KERNEL, "%s_%s", 338 iio_ev_type_text[type], 339 iio_ev_info_text[i]); 340 if (postfix == NULL) 341 return -ENOMEM; 342 343 if (i == IIO_EV_INFO_ENABLE) { 344 show = iio_ev_state_show; 345 store = iio_ev_state_store; 346 } else { 347 show = iio_ev_value_show; 348 store = iio_ev_value_store; 349 } 350 351 ret = __iio_add_chan_devattr(postfix, chan, show, store, 352 (i << 16) | spec_index, shared_by, &indio_dev->dev, 353 &indio_dev->event_interface->dev_attr_list); 354 kfree(postfix); 355 356 if ((ret == -EBUSY) && (shared_by != IIO_SEPARATE)) 357 continue; 358 359 if (ret) 360 return ret; 361 362 attrcount++; 363 } 364 365 return attrcount; 366 } 367 368 static int iio_device_add_event_sysfs(struct iio_dev *indio_dev, 369 struct iio_chan_spec const *chan) 370 { 371 int ret = 0, i, attrcount = 0; 372 enum iio_event_direction dir; 373 enum iio_event_type type; 374 375 for (i = 0; i < chan->num_event_specs; i++) { 376 type = chan->event_spec[i].type; 377 dir = chan->event_spec[i].dir; 378 379 ret = iio_device_add_event(indio_dev, chan, i, type, dir, 380 IIO_SEPARATE, &chan->event_spec[i].mask_separate); 381 if (ret < 0) 382 return ret; 383 attrcount += ret; 384 385 ret = iio_device_add_event(indio_dev, chan, i, type, dir, 386 IIO_SHARED_BY_TYPE, 387 &chan->event_spec[i].mask_shared_by_type); 388 if (ret < 0) 389 return ret; 390 attrcount += ret; 391 392 ret = iio_device_add_event(indio_dev, chan, i, type, dir, 393 IIO_SHARED_BY_DIR, 394 &chan->event_spec[i].mask_shared_by_dir); 395 if (ret < 0) 396 return ret; 397 attrcount += ret; 398 399 ret = iio_device_add_event(indio_dev, chan, i, type, dir, 400 IIO_SHARED_BY_ALL, 401 &chan->event_spec[i].mask_shared_by_all); 402 if (ret < 0) 403 return ret; 404 attrcount += ret; 405 } 406 ret = attrcount; 407 return ret; 408 } 409 410 static inline int __iio_add_event_config_attrs(struct iio_dev *indio_dev) 411 { 412 int j, ret, attrcount = 0; 413 414 /* Dynamically created from the channels array */ 415 for (j = 0; j < indio_dev->num_channels; j++) { 416 ret = iio_device_add_event_sysfs(indio_dev, 417 &indio_dev->channels[j]); 418 if (ret < 0) 419 return ret; 420 attrcount += ret; 421 } 422 return attrcount; 423 } 424 425 static bool iio_check_for_dynamic_events(struct iio_dev *indio_dev) 426 { 427 int j; 428 429 for (j = 0; j < indio_dev->num_channels; j++) { 430 if (indio_dev->channels[j].num_event_specs != 0) 431 return true; 432 } 433 return false; 434 } 435 436 static void iio_setup_ev_int(struct iio_event_interface *ev_int) 437 { 438 INIT_KFIFO(ev_int->det_events); 439 init_waitqueue_head(&ev_int->wait); 440 mutex_init(&ev_int->read_lock); 441 } 442 443 static const char *iio_event_group_name = "events"; 444 int iio_device_register_eventset(struct iio_dev *indio_dev) 445 { 446 struct iio_dev_attr *p; 447 int ret = 0, attrcount_orig = 0, attrcount, attrn; 448 struct attribute **attr; 449 450 if (!(indio_dev->info->event_attrs || 451 iio_check_for_dynamic_events(indio_dev))) 452 return 0; 453 454 indio_dev->event_interface = 455 kzalloc(sizeof(struct iio_event_interface), GFP_KERNEL); 456 if (indio_dev->event_interface == NULL) 457 return -ENOMEM; 458 459 INIT_LIST_HEAD(&indio_dev->event_interface->dev_attr_list); 460 461 iio_setup_ev_int(indio_dev->event_interface); 462 if (indio_dev->info->event_attrs != NULL) { 463 attr = indio_dev->info->event_attrs->attrs; 464 while (*attr++ != NULL) 465 attrcount_orig++; 466 } 467 attrcount = attrcount_orig; 468 if (indio_dev->channels) { 469 ret = __iio_add_event_config_attrs(indio_dev); 470 if (ret < 0) 471 goto error_free_setup_event_lines; 472 attrcount += ret; 473 } 474 475 indio_dev->event_interface->group.name = iio_event_group_name; 476 indio_dev->event_interface->group.attrs = kcalloc(attrcount + 1, 477 sizeof(indio_dev->event_interface->group.attrs[0]), 478 GFP_KERNEL); 479 if (indio_dev->event_interface->group.attrs == NULL) { 480 ret = -ENOMEM; 481 goto error_free_setup_event_lines; 482 } 483 if (indio_dev->info->event_attrs) 484 memcpy(indio_dev->event_interface->group.attrs, 485 indio_dev->info->event_attrs->attrs, 486 sizeof(indio_dev->event_interface->group.attrs[0]) 487 *attrcount_orig); 488 attrn = attrcount_orig; 489 /* Add all elements from the list. */ 490 list_for_each_entry(p, 491 &indio_dev->event_interface->dev_attr_list, 492 l) 493 indio_dev->event_interface->group.attrs[attrn++] = 494 &p->dev_attr.attr; 495 indio_dev->groups[indio_dev->groupcounter++] = 496 &indio_dev->event_interface->group; 497 498 return 0; 499 500 error_free_setup_event_lines: 501 iio_free_chan_devattr_list(&indio_dev->event_interface->dev_attr_list); 502 kfree(indio_dev->event_interface); 503 indio_dev->event_interface = NULL; 504 return ret; 505 } 506 507 /** 508 * iio_device_wakeup_eventset - Wakes up the event waitqueue 509 * @indio_dev: The IIO device 510 * 511 * Wakes up the event waitqueue used for poll() and blocking read(). 512 * Should usually be called when the device is unregistered. 513 */ 514 void iio_device_wakeup_eventset(struct iio_dev *indio_dev) 515 { 516 if (indio_dev->event_interface == NULL) 517 return; 518 wake_up(&indio_dev->event_interface->wait); 519 } 520 521 void iio_device_unregister_eventset(struct iio_dev *indio_dev) 522 { 523 if (indio_dev->event_interface == NULL) 524 return; 525 iio_free_chan_devattr_list(&indio_dev->event_interface->dev_attr_list); 526 kfree(indio_dev->event_interface->group.attrs); 527 kfree(indio_dev->event_interface); 528 } 529