drivers/staging/iio/industrialio-trigger.c

   1 /* The industrial I/O core, trigger handling functions
   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
  10 #include <linux/kernel.h>
  11 #include <linux/idr.h>
  12 #include <linux/err.h>
  13 #include <linux/device.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/list.h>
  16 #include <linux/slab.h>
  17
  18 #include "iio.h"
  19 #include "trigger.h"
  20 #include "iio_core.h"
  21 #include "iio_core_trigger.h"
  22
  23 /* RFC - Question of approach
  24  * Make the common case (single sensor single trigger)
  25  * simple by starting trigger capture from when first sensors
  26  * is added.
  27  *
  28  * Complex simultaneous start requires use of 'hold' functionality
  29  * of the trigger. (not implemented)
  30  *
  31  * Any other suggestions?
  32  */
  33
  34 static DEFINE_IDR(iio_trigger_idr);
  35 static DEFINE_SPINLOCK(iio_trigger_idr_lock);
  36
  37 /* Single list of all available triggers */
  38 static LIST_HEAD(iio_trigger_list);
  39 static DEFINE_MUTEX(iio_trigger_list_lock);
  40
  41 /**
  42  * iio_trigger_read_name() - retrieve useful identifying name
  43  **/
  44 static ssize_t iio_trigger_read_name(struct device *dev,
  45                                      struct device_attribute *attr,
  46                                      char *buf)
  47 {
  48         struct iio_trigger *trig = dev_get_drvdata(dev);
  49         return sprintf(buf, "%s\n", trig->name);
  50 }
  51
  52 static DEVICE_ATTR(name, S_IRUGO, iio_trigger_read_name, NULL);
  53
  54 /**
  55  * iio_trigger_register_sysfs() - create a device for this trigger
  56  * @trig_info:  the trigger
  57  *
  58  * Also adds any control attribute registered by the trigger driver
  59  **/
  60 static int iio_trigger_register_sysfs(struct iio_trigger *trig_info)
  61 {
  62         return sysfs_add_file_to_group(&trig_info->dev.kobj,
  63                                        &dev_attr_name.attr,
  64                                        NULL);
  65 }
  66
  67 static void iio_trigger_unregister_sysfs(struct iio_trigger *trig_info)
  68 {
  69         sysfs_remove_file_from_group(&trig_info->dev.kobj,
  70                                            &dev_attr_name.attr,
  71                                            NULL);
  72 }
  73
  74
  75 /**
  76  * iio_trigger_register_id() - get a unique id for this trigger
  77  * @trig_info:  the trigger
  78  **/
  79 static int iio_trigger_register_id(struct iio_trigger *trig_info)
  80 {
  81         int ret = 0;
  82
  83 idr_again:
  84         if (unlikely(idr_pre_get(&iio_trigger_idr, GFP_KERNEL) == 0))
  85                 return -ENOMEM;
  86
  87         spin_lock(&iio_trigger_idr_lock);
  88         ret = idr_get_new(&iio_trigger_idr, NULL, &trig_info->id);
  89         spin_unlock(&iio_trigger_idr_lock);
  90         if (unlikely(ret == -EAGAIN))
  91                 goto idr_again;
  92         else if (likely(!ret))
  93                 trig_info->id = trig_info->id & MAX_ID_MASK;
  94
  95         return ret;
  96 }
  97
  98 /**
  99  * iio_trigger_unregister_id() - free up unique id for use by another trigger
 100  * @trig_info: the trigger
 101  **/
 102 static void iio_trigger_unregister_id(struct iio_trigger *trig_info)
 103 {
 104         spin_lock(&iio_trigger_idr_lock);
 105         idr_remove(&iio_trigger_idr, trig_info->id);
 106         spin_unlock(&iio_trigger_idr_lock);
 107 }
 108
 109 int iio_trigger_register(struct iio_trigger *trig_info)
 110 {
 111         int ret;
 112
 113         ret = iio_trigger_register_id(trig_info);
 114         if (ret)
 115                 goto error_ret;
 116         /* Set the name used for the sysfs directory etc */
 117         dev_set_name(&trig_info->dev, "trigger%ld",
 118                      (unsigned long) trig_info->id);
 119
 120         ret = device_add(&trig_info->dev);
 121         if (ret)
 122                 goto error_unregister_id;
 123
 124         ret = iio_trigger_register_sysfs(trig_info);
 125         if (ret)
 126                 goto error_device_del;
 127
 128         /* Add to list of available triggers held by the IIO core */
 129         mutex_lock(&iio_trigger_list_lock);
 130         list_add_tail(&trig_info->list, &iio_trigger_list);
 131         mutex_unlock(&iio_trigger_list_lock);
 132
 133         return 0;
 134
 135 error_device_del:
 136         device_del(&trig_info->dev);
 137 error_unregister_id:
 138         iio_trigger_unregister_id(trig_info);
 139 error_ret:
 140         return ret;
 141 }
 142 EXPORT_SYMBOL(iio_trigger_register);
 143
 144 void iio_trigger_unregister(struct iio_trigger *trig_info)
 145 {
 146         mutex_lock(&iio_trigger_list_lock);
 147         list_del(&trig_info->list);
 148         mutex_unlock(&iio_trigger_list_lock);
 149
 150         iio_trigger_unregister_sysfs(trig_info);
 151         iio_trigger_unregister_id(trig_info);
 152         /* Possible issue in here */
 153         device_unregister(&trig_info->dev);
 154 }
 155 EXPORT_SYMBOL(iio_trigger_unregister);
 156
 157 static struct iio_trigger *iio_trigger_find_by_name(const char *name,
 158                                                     size_t len)
 159 {
 160         struct iio_trigger *trig = NULL, *iter;
 161
 162         mutex_lock(&iio_trigger_list_lock);
 163         list_for_each_entry(iter, &iio_trigger_list, list)
 164                 if (sysfs_streq(iter->name, name)) {
 165                         trig = iter;
 166                         break;
 167                 }
 168         mutex_unlock(&iio_trigger_list_lock);
 169
 170         return trig;
 171 }
 172
 173 void iio_trigger_poll(struct iio_trigger *trig, s64 time)
 174 {
 175         int i;
 176         if (!trig->use_count) {
 177                 for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++)
 178                         if (trig->subirqs[i].enabled) {
 179                                 trig->use_count++;
 180                                 generic_handle_irq(trig->subirq_base + i);
 181                         }
 182         }
 183 }
 184 EXPORT_SYMBOL(iio_trigger_poll);
 185
 186 irqreturn_t iio_trigger_generic_data_rdy_poll(int irq, void *private)
 187 {
 188         iio_trigger_poll(private, iio_get_time_ns());
 189         return IRQ_HANDLED;
 190 }
 191 EXPORT_SYMBOL(iio_trigger_generic_data_rdy_poll);
 192
 193 void iio_trigger_poll_chained(struct iio_trigger *trig, s64 time)
 194 {
 195         int i;
 196         if (!trig->use_count) {
 197                 for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++)
 198                         if (trig->subirqs[i].enabled) {
 199                                 trig->use_count++;
 200                                 handle_nested_irq(trig->subirq_base + i);
 201                         }
 202         }
 203 }
 204 EXPORT_SYMBOL(iio_trigger_poll_chained);
 205
 206 void iio_trigger_notify_done(struct iio_trigger *trig)
 207 {
 208         trig->use_count--;
 209         if (trig->use_count == 0 && trig->ops && trig->ops->try_reenable)
 210                 if (trig->ops->try_reenable(trig)) {
 211                         /* Missed and interrupt so launch new poll now */
 212                         iio_trigger_poll(trig, 0);
 213                 }
 214 }
 215 EXPORT_SYMBOL(iio_trigger_notify_done);
 216
 217 /* Trigger Consumer related functions */
 218
 219 /* Complexity in here.  With certain triggers (datardy) an acknowledgement
 220  * may be needed if the pollfuncs do not include the data read for the
 221  * triggering device.
 222  * This is not currently handled.  Alternative of not enabling trigger unless
 223  * the relevant function is in there may be the best option.
 224  */
 225 /* Worth protecting against double additions?*/
 226 int iio_trigger_attach_poll_func(struct iio_trigger *trig,
 227                                  struct iio_poll_func *pf)
 228 {
 229         int ret = 0;
 230         bool notinuse
 231                 = bitmap_empty(trig->pool, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
 232
 233         /* Prevent the module being removed whilst attached to a trigger */
 234         __module_get(pf->indio_dev->info->driver_module);
 235         pf->irq = iio_trigger_get_irq(trig);
 236         ret = request_threaded_irq(pf->irq, pf->h, pf->thread,
 237                                    pf->type, pf->name,
 238                                    pf);
 239         if (trig->ops && trig->ops->set_trigger_state && notinuse)
 240                 ret = trig->ops->set_trigger_state(trig, true);
 241
 242         return ret;
 243 }
 244 EXPORT_SYMBOL(iio_trigger_attach_poll_func);
 245
 246 int iio_trigger_dettach_poll_func(struct iio_trigger *trig,
 247                                   struct iio_poll_func *pf)
 248 {
 249         int ret = 0;
 250         bool no_other_users
 251                 = (bitmap_weight(trig->pool,
 252                                  CONFIG_IIO_CONSUMERS_PER_TRIGGER)
 253                    == 1);
 254         if (trig->ops && trig->ops->set_trigger_state && no_other_users) {
 255                 ret = trig->ops->set_trigger_state(trig, false);
 256                 if (ret)
 257                         goto error_ret;
 258         }
 259         iio_trigger_put_irq(trig, pf->irq);
 260         free_irq(pf->irq, pf);
 261         module_put(pf->indio_dev->info->driver_module);
 262
 263 error_ret:
 264         return ret;
 265 }
 266 EXPORT_SYMBOL(iio_trigger_dettach_poll_func);
 267
 268 irqreturn_t iio_pollfunc_store_time(int irq, void *p)
 269 {
 270         struct iio_poll_func *pf = p;
 271         pf->timestamp = iio_get_time_ns();
 272         return IRQ_WAKE_THREAD;
 273 }
 274 EXPORT_SYMBOL(iio_pollfunc_store_time);
 275
 276 struct iio_poll_func
 277 *iio_alloc_pollfunc(irqreturn_t (*h)(int irq, void *p),
 278                     irqreturn_t (*thread)(int irq, void *p),
 279                     int type,
 280                     struct iio_dev *indio_dev,
 281                     const char *fmt,
 282                     ...)
 283 {
 284         va_list vargs;
 285         struct iio_poll_func *pf;
 286
 287         pf = kmalloc(sizeof *pf, GFP_KERNEL);
 288         if (pf == NULL)
 289                 return NULL;
 290         va_start(vargs, fmt);
 291         pf->name = kvasprintf(GFP_KERNEL, fmt, vargs);
 292         va_end(vargs);
 293         if (pf->name == NULL) {
 294                 kfree(pf);
 295                 return NULL;
 296         }
 297         pf->h = h;
 298         pf->thread = thread;
 299         pf->type = type;
 300         pf->indio_dev = indio_dev;
 301
 302         return pf;
 303 }
 304 EXPORT_SYMBOL_GPL(iio_alloc_pollfunc);
 305
 306 void iio_dealloc_pollfunc(struct iio_poll_func *pf)
 307 {
 308         kfree(pf->name);
 309         kfree(pf);
 310 }
 311 EXPORT_SYMBOL_GPL(iio_dealloc_pollfunc);
 312
 313 /**
 314  * iio_trigger_read_currrent() - trigger consumer sysfs query which trigger
 315  *
 316  * For trigger consumers the current_trigger interface allows the trigger
 317  * used by the device to be queried.
 318  **/
 319 static ssize_t iio_trigger_read_current(struct device *dev,
 320                                         struct device_attribute *attr,
 321                                         char *buf)
 322 {
 323         struct iio_dev *dev_info = dev_get_drvdata(dev);
 324         int len = 0;
 325         if (dev_info->trig)
 326                 len = sprintf(buf,
 327                               "%s\n",
 328                               dev_info->trig->name);
 329         return len;
 330 }
 331
 332 /**
 333  * iio_trigger_write_current() trigger consumer sysfs set current trigger
 334  *
 335  * For trigger consumers the current_trigger interface allows the trigger
 336  * used for this device to be specified at run time based on the triggers
 337  * name.
 338  **/
 339 static ssize_t iio_trigger_write_current(struct device *dev,
 340                                          struct device_attribute *attr,
 341                                          const char *buf,
 342                                          size_t len)
 343 {
 344         struct iio_dev *dev_info = dev_get_drvdata(dev);
 345         struct iio_trigger *oldtrig = dev_info->trig;
 346         struct iio_trigger *trig;
 347         int ret;
 348
 349         mutex_lock(&dev_info->mlock);
 350         if (dev_info->currentmode == INDIO_RING_TRIGGERED) {
 351                 mutex_unlock(&dev_info->mlock);
 352                 return -EBUSY;
 353         }
 354         mutex_unlock(&dev_info->mlock);
 355
 356         trig = iio_trigger_find_by_name(buf, len);
 357
 358         if (trig && dev_info->info->validate_trigger) {
 359                 ret = dev_info->info->validate_trigger(dev_info, trig);
 360                 if (ret)
 361                         return ret;
 362         }
 363
 364         if (trig && trig->ops && trig->ops->validate_device) {
 365                 ret = trig->ops->validate_device(trig, dev_info);
 366                 if (ret)
 367                         return ret;
 368         }
 369
 370         dev_info->trig = trig;
 371
 372         if (oldtrig && dev_info->trig != oldtrig)
 373                 iio_put_trigger(oldtrig);
 374         if (dev_info->trig)
 375                 iio_get_trigger(dev_info->trig);
 376
 377         return len;
 378 }
 379
 380 static DEVICE_ATTR(current_trigger, S_IRUGO | S_IWUSR,
 381                    iio_trigger_read_current,
 382                    iio_trigger_write_current);
 383
 384 static struct attribute *iio_trigger_consumer_attrs[] = {
 385         &dev_attr_current_trigger.attr,
 386         NULL,
 387 };
 388
 389 static const struct attribute_group iio_trigger_consumer_attr_group = {
 390         .name = "trigger",
 391         .attrs = iio_trigger_consumer_attrs,
 392 };
 393
 394 static void iio_trig_release(struct device *device)
 395 {
 396         struct iio_trigger *trig = to_iio_trigger(device);
 397         int i;
 398
 399         if (trig->subirq_base) {
 400                 for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
 401                         irq_modify_status(trig->subirq_base + i,
 402                                           IRQ_NOAUTOEN,
 403                                           IRQ_NOREQUEST | IRQ_NOPROBE);
 404                         irq_set_chip(trig->subirq_base + i,
 405                                      NULL);
 406                         irq_set_handler(trig->subirq_base + i,
 407                                         NULL);
 408                 }
 409
 410                 irq_free_descs(trig->subirq_base,
 411                                CONFIG_IIO_CONSUMERS_PER_TRIGGER);
 412         }
 413         kfree(trig->name);
 414         kfree(trig);
 415         iio_put();
 416 }
 417
 418 static struct device_type iio_trig_type = {
 419         .release = iio_trig_release,
 420 };
 421
 422 static void iio_trig_subirqmask(struct irq_data *d)
 423 {
 424         struct irq_chip *chip = irq_data_get_irq_chip(d);
 425         struct iio_trigger *trig
 426                 = container_of(chip,
 427                                struct iio_trigger, subirq_chip);
 428         trig->subirqs[d->irq - trig->subirq_base].enabled = false;
 429 }
 430
 431 static void iio_trig_subirqunmask(struct irq_data *d)
 432 {
 433         struct irq_chip *chip = irq_data_get_irq_chip(d);
 434         struct iio_trigger *trig
 435                 = container_of(chip,
 436                                struct iio_trigger, subirq_chip);
 437         trig->subirqs[d->irq - trig->subirq_base].enabled = true;
 438 }
 439
 440 struct iio_trigger *iio_allocate_trigger(const char *fmt, ...)
 441 {
 442         va_list vargs;
 443         struct iio_trigger *trig;
 444         trig = kzalloc(sizeof *trig, GFP_KERNEL);
 445         if (trig) {
 446                 int i;
 447                 trig->dev.type = &iio_trig_type;
 448                 trig->dev.bus = &iio_bus_type;
 449                 device_initialize(&trig->dev);
 450                 dev_set_drvdata(&trig->dev, (void *)trig);
 451
 452                 mutex_init(&trig->pool_lock);
 453                 trig->subirq_base
 454                         = irq_alloc_descs(-1, 0,
 455                                           CONFIG_IIO_CONSUMERS_PER_TRIGGER,
 456                                           0);
 457                 if (trig->subirq_base < 0) {
 458                         kfree(trig);
 459                         return NULL;
 460                 }
 461                 va_start(vargs, fmt);
 462                 trig->name = kvasprintf(GFP_KERNEL, fmt, vargs);
 463                 va_end(vargs);
 464                 if (trig->name == NULL) {
 465                         irq_free_descs(trig->subirq_base,
 466                                        CONFIG_IIO_CONSUMERS_PER_TRIGGER);
 467                         kfree(trig);
 468                         return NULL;
 469                 }
 470                 trig->subirq_chip.name = trig->name;
 471                 trig->subirq_chip.irq_mask = &iio_trig_subirqmask;
 472                 trig->subirq_chip.irq_unmask = &iio_trig_subirqunmask;
 473                 for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
 474                         irq_set_chip(trig->subirq_base + i,
 475                                      &trig->subirq_chip);
 476                         irq_set_handler(trig->subirq_base + i,
 477                                         &handle_simple_irq);
 478                         irq_modify_status(trig->subirq_base + i,
 479                                           IRQ_NOREQUEST | IRQ_NOAUTOEN,
 480                                           IRQ_NOPROBE);
 481                 }
 482                 iio_get();
 483                 get_device(&trig->dev);
 484         }
 485         return trig;
 486 }
 487 EXPORT_SYMBOL(iio_allocate_trigger);
 488
 489 void iio_free_trigger(struct iio_trigger *trig)
 490 {
 491         if (trig)
 492                 put_device(&trig->dev);
 493 }
 494 EXPORT_SYMBOL(iio_free_trigger);
 495
 496 int iio_device_register_trigger_consumer(struct iio_dev *dev_info)
 497 {
 498         int ret;
 499         ret = sysfs_create_group(&dev_info->dev.kobj,
 500                                  &iio_trigger_consumer_attr_group);
 501         return ret;
 502 }
 503 EXPORT_SYMBOL(iio_device_register_trigger_consumer);
 504
 505 int iio_device_unregister_trigger_consumer(struct iio_dev *dev_info)
 506 {
 507         /* Clean up and associated but not attached triggers references */
 508         if (dev_info->trig)
 509                 iio_put_trigger(dev_info->trig);
 510         sysfs_remove_group(&dev_info->dev.kobj,
 511                            &iio_trigger_consumer_attr_group);
 512         return 0;
 513 }
 514 EXPORT_SYMBOL(iio_device_unregister_trigger_consumer);
 515
 516 int iio_triggered_ring_postenable(struct iio_dev *indio_dev)
 517 {
 518         return indio_dev->trig
 519                 ? iio_trigger_attach_poll_func(indio_dev->trig,
 520                                                indio_dev->pollfunc)
 521                 : 0;
 522 }
 523 EXPORT_SYMBOL(iio_triggered_ring_postenable);
 524
 525 int iio_triggered_ring_predisable(struct iio_dev *indio_dev)
 526 {
 527         return indio_dev->trig
 528                 ? iio_trigger_dettach_poll_func(indio_dev->trig,
 529                                                 indio_dev->pollfunc)
 530                 : 0;
 531 }
 532 EXPORT_SYMBOL(iio_triggered_ring_predisable);