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 #include "trigger_consumer.h"
  23
  24 /* RFC - Question of approach
  25  * Make the common case (single sensor single trigger)
  26  * simple by starting trigger capture from when first sensors
  27  * is added.
  28  *
  29  * Complex simultaneous start requires use of 'hold' functionality
  30  * of the trigger. (not implemented)
  31  *
  32  * Any other suggestions?
  33  */
  34
  35 static DEFINE_IDR(iio_trigger_idr);
  36 static DEFINE_SPINLOCK(iio_trigger_idr_lock);
  37
  38 /* Single list of all available triggers */
  39 static LIST_HEAD(iio_trigger_list);
  40 static DEFINE_MUTEX(iio_trigger_list_lock);
  41
  42 /**
  43  * iio_trigger_read_name() - retrieve useful identifying name
  44  **/
  45 static ssize_t iio_trigger_read_name(struct device *dev,
  46                                      struct device_attribute *attr,
  47                                      char *buf)
  48 {
  49         struct iio_trigger *trig = dev_get_drvdata(dev);
  50         return sprintf(buf, "%s\n", trig->name);
  51 }
  52
  53 static DEVICE_ATTR(name, S_IRUGO, iio_trigger_read_name, NULL);
  54
  55 /**
  56  * iio_trigger_register_sysfs() - create a device for this trigger
  57  * @trig_info:  the trigger
  58  *
  59  * Also adds any control attribute registered by the trigger driver
  60  **/
  61 static int iio_trigger_register_sysfs(struct iio_trigger *trig_info)
  62 {
  63         return sysfs_add_file_to_group(&trig_info->dev.kobj,
  64                                        &dev_attr_name.attr,
  65                                        NULL);
  66 }
  67
  68 static void iio_trigger_unregister_sysfs(struct iio_trigger *trig_info)
  69 {
  70         sysfs_remove_file_from_group(&trig_info->dev.kobj,
  71                                            &dev_attr_name.attr,
  72                                            NULL);
  73 }
  74
  75
  76 /**
  77  * iio_trigger_register_id() - get a unique id for this trigger
  78  * @trig_info:  the trigger
  79  **/
  80 static int iio_trigger_register_id(struct iio_trigger *trig_info)
  81 {
  82         int ret = 0;
  83
  84 idr_again:
  85         if (unlikely(idr_pre_get(&iio_trigger_idr, GFP_KERNEL) == 0))
  86                 return -ENOMEM;
  87
  88         spin_lock(&iio_trigger_idr_lock);
  89         ret = idr_get_new(&iio_trigger_idr, NULL, &trig_info->id);
  90         spin_unlock(&iio_trigger_idr_lock);
  91         if (unlikely(ret == -EAGAIN))
  92                 goto idr_again;
  93         else if (likely(!ret))
  94                 trig_info->id = trig_info->id & MAX_ID_MASK;
  95
  96         return ret;
  97 }
  98
  99 /**
 100  * iio_trigger_unregister_id() - free up unique id for use by another trigger
 101  * @trig_info: the trigger
 102  **/
 103 static void iio_trigger_unregister_id(struct iio_trigger *trig_info)
 104 {
 105         spin_lock(&iio_trigger_idr_lock);
 106         idr_remove(&iio_trigger_idr, trig_info->id);
 107         spin_unlock(&iio_trigger_idr_lock);
 108 }
 109
 110 int iio_trigger_register(struct iio_trigger *trig_info)
 111 {
 112         int ret;
 113
 114         ret = iio_trigger_register_id(trig_info);
 115         if (ret)
 116                 goto error_ret;
 117         /* Set the name used for the sysfs directory etc */
 118         dev_set_name(&trig_info->dev, "trigger%ld",
 119                      (unsigned long) trig_info->id);
 120
 121         ret = device_add(&trig_info->dev);
 122         if (ret)
 123                 goto error_unregister_id;
 124
 125         ret = iio_trigger_register_sysfs(trig_info);
 126         if (ret)
 127                 goto error_device_del;
 128
 129         /* Add to list of available triggers held by the IIO core */
 130         mutex_lock(&iio_trigger_list_lock);
 131         list_add_tail(&trig_info->list, &iio_trigger_list);
 132         mutex_unlock(&iio_trigger_list_lock);
 133
 134         return 0;
 135
 136 error_device_del:
 137         device_del(&trig_info->dev);
 138 error_unregister_id:
 139         iio_trigger_unregister_id(trig_info);
 140 error_ret:
 141         return ret;
 142 }
 143 EXPORT_SYMBOL(iio_trigger_register);
 144
 145 void iio_trigger_unregister(struct iio_trigger *trig_info)
 146 {
 147         mutex_lock(&iio_trigger_list_lock);
 148         list_del(&trig_info->list);
 149         mutex_unlock(&iio_trigger_list_lock);
 150
 151         iio_trigger_unregister_sysfs(trig_info);
 152         iio_trigger_unregister_id(trig_info);
 153         /* Possible issue in here */
 154         device_unregister(&trig_info->dev);
 155 }
 156 EXPORT_SYMBOL(iio_trigger_unregister);
 157
 158 static struct iio_trigger *iio_trigger_find_by_name(const char *name,
 159                                                     size_t len)
 160 {
 161         struct iio_trigger *trig = NULL, *iter;
 162
 163         mutex_lock(&iio_trigger_list_lock);
 164         list_for_each_entry(iter, &iio_trigger_list, list)
 165                 if (sysfs_streq(iter->name, name)) {
 166                         trig = iter;
 167                         break;
 168                 }
 169         mutex_unlock(&iio_trigger_list_lock);
 170
 171         return trig;
 172 }
 173
 174 void iio_trigger_poll(struct iio_trigger *trig, s64 time)
 175 {
 176         int i;
 177         if (!trig->use_count)
 178                 for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++)
 179                         if (trig->subirqs[i].enabled) {
 180                                 trig->use_count++;
 181                                 generic_handle_irq(trig->subirq_base + i);
 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 static int iio_trigger_get_irq(struct iio_trigger *trig)
 219 {
 220         int ret;
 221         mutex_lock(&trig->pool_lock);
 222         ret = bitmap_find_free_region(trig->pool,
 223                                       CONFIG_IIO_CONSUMERS_PER_TRIGGER,
 224                                       ilog2(1));
 225         mutex_unlock(&trig->pool_lock);
 226         if (ret >= 0)
 227                 ret += trig->subirq_base;
 228
 229         return ret;
 230 }
 231
 232 static void iio_trigger_put_irq(struct iio_trigger *trig, int irq)
 233 {
 234         mutex_lock(&trig->pool_lock);
 235         clear_bit(irq - trig->subirq_base, trig->pool);
 236         mutex_unlock(&trig->pool_lock);
 237 }
 238
 239 /* Complexity in here.  With certain triggers (datardy) an acknowledgement
 240  * may be needed if the pollfuncs do not include the data read for the
 241  * triggering device.
 242  * This is not currently handled.  Alternative of not enabling trigger unless
 243  * the relevant function is in there may be the best option.
 244  */
 245 /* Worth protecting against double additions?*/
 246 static int iio_trigger_attach_poll_func(struct iio_trigger *trig,
 247                                         struct iio_poll_func *pf)
 248 {
 249         int ret = 0;
 250         bool notinuse
 251                 = bitmap_empty(trig->pool, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
 252
 253         /* Prevent the module being removed whilst attached to a trigger */
 254         __module_get(pf->indio_dev->info->driver_module);
 255         pf->irq = iio_trigger_get_irq(trig);
 256         ret = request_threaded_irq(pf->irq, pf->h, pf->thread,
 257                                    pf->type, pf->name,
 258                                    pf);
 259         if (trig->ops && trig->ops->set_trigger_state && notinuse)
 260                 ret = trig->ops->set_trigger_state(trig, true);
 261
 262         return ret;
 263 }
 264
 265 static int iio_trigger_dettach_poll_func(struct iio_trigger *trig,
 266                                          struct iio_poll_func *pf)
 267 {
 268         int ret = 0;
 269         bool no_other_users
 270                 = (bitmap_weight(trig->pool,
 271                                  CONFIG_IIO_CONSUMERS_PER_TRIGGER)
 272                    == 1);
 273         if (trig->ops && trig->ops->set_trigger_state && no_other_users) {
 274                 ret = trig->ops->set_trigger_state(trig, false);
 275                 if (ret)
 276                         goto error_ret;
 277         }
 278         iio_trigger_put_irq(trig, pf->irq);
 279         free_irq(pf->irq, pf);
 280         module_put(pf->indio_dev->info->driver_module);
 281
 282 error_ret:
 283         return ret;
 284 }
 285
 286 irqreturn_t iio_pollfunc_store_time(int irq, void *p)
 287 {
 288         struct iio_poll_func *pf = p;
 289         pf->timestamp = iio_get_time_ns();
 290         return IRQ_WAKE_THREAD;
 291 }
 292 EXPORT_SYMBOL(iio_pollfunc_store_time);
 293
 294 struct iio_poll_func
 295 *iio_alloc_pollfunc(irqreturn_t (*h)(int irq, void *p),
 296                     irqreturn_t (*thread)(int irq, void *p),
 297                     int type,
 298                     struct iio_dev *indio_dev,
 299                     const char *fmt,
 300                     ...)
 301 {
 302         va_list vargs;
 303         struct iio_poll_func *pf;
 304
 305         pf = kmalloc(sizeof *pf, GFP_KERNEL);
 306         if (pf == NULL)
 307                 return NULL;
 308         va_start(vargs, fmt);
 309         pf->name = kvasprintf(GFP_KERNEL, fmt, vargs);
 310         va_end(vargs);
 311         if (pf->name == NULL) {
 312                 kfree(pf);
 313                 return NULL;
 314         }
 315         pf->h = h;
 316         pf->thread = thread;
 317         pf->type = type;
 318         pf->indio_dev = indio_dev;
 319
 320         return pf;
 321 }
 322 EXPORT_SYMBOL_GPL(iio_alloc_pollfunc);
 323
 324 void iio_dealloc_pollfunc(struct iio_poll_func *pf)
 325 {
 326         kfree(pf->name);
 327         kfree(pf);
 328 }
 329 EXPORT_SYMBOL_GPL(iio_dealloc_pollfunc);
 330
 331 /**
 332  * iio_trigger_read_currrent() - trigger consumer sysfs query which trigger
 333  *
 334  * For trigger consumers the current_trigger interface allows the trigger
 335  * used by the device to be queried.
 336  **/
 337 static ssize_t iio_trigger_read_current(struct device *dev,
 338                                         struct device_attribute *attr,
 339                                         char *buf)
 340 {
 341         struct iio_dev *dev_info = dev_get_drvdata(dev);
 342
 343         if (dev_info->trig)
 344                 return sprintf(buf, "%s\n", dev_info->trig->name);
 345         return 0;
 346 }
 347
 348 /**
 349  * iio_trigger_write_current() trigger consumer sysfs set current trigger
 350  *
 351  * For trigger consumers the current_trigger interface allows the trigger
 352  * used for this device to be specified at run time based on the triggers
 353  * name.
 354  **/
 355 static ssize_t iio_trigger_write_current(struct device *dev,
 356                                          struct device_attribute *attr,
 357                                          const char *buf,
 358                                          size_t len)
 359 {
 360         struct iio_dev *dev_info = dev_get_drvdata(dev);
 361         struct iio_trigger *oldtrig = dev_info->trig;
 362         struct iio_trigger *trig;
 363         int ret;
 364
 365         mutex_lock(&dev_info->mlock);
 366         if (dev_info->currentmode == INDIO_RING_TRIGGERED) {
 367                 mutex_unlock(&dev_info->mlock);
 368                 return -EBUSY;
 369         }
 370         mutex_unlock(&dev_info->mlock);
 371
 372         trig = iio_trigger_find_by_name(buf, len);
 373
 374         if (trig && dev_info->info->validate_trigger) {
 375                 ret = dev_info->info->validate_trigger(dev_info, trig);
 376                 if (ret)
 377                         return ret;
 378         }
 379
 380         if (trig && trig->ops && trig->ops->validate_device) {
 381                 ret = trig->ops->validate_device(trig, dev_info);
 382                 if (ret)
 383                         return ret;
 384         }
 385
 386         dev_info->trig = trig;
 387
 388         if (oldtrig && dev_info->trig != oldtrig)
 389                 iio_put_trigger(oldtrig);
 390         if (dev_info->trig)
 391                 iio_get_trigger(dev_info->trig);
 392
 393         return len;
 394 }
 395
 396 static DEVICE_ATTR(current_trigger, S_IRUGO | S_IWUSR,
 397                    iio_trigger_read_current,
 398                    iio_trigger_write_current);
 399
 400 static struct attribute *iio_trigger_consumer_attrs[] = {
 401         &dev_attr_current_trigger.attr,
 402         NULL,
 403 };
 404
 405 static const struct attribute_group iio_trigger_consumer_attr_group = {
 406         .name = "trigger",
 407         .attrs = iio_trigger_consumer_attrs,
 408 };
 409
 410 static void iio_trig_release(struct device *device)
 411 {
 412         struct iio_trigger *trig = to_iio_trigger(device);
 413         int i;
 414
 415         if (trig->subirq_base) {
 416                 for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
 417                         irq_modify_status(trig->subirq_base + i,
 418                                           IRQ_NOAUTOEN,
 419                                           IRQ_NOREQUEST | IRQ_NOPROBE);
 420                         irq_set_chip(trig->subirq_base + i,
 421                                      NULL);
 422                         irq_set_handler(trig->subirq_base + i,
 423                                         NULL);
 424                 }
 425
 426                 irq_free_descs(trig->subirq_base,
 427                                CONFIG_IIO_CONSUMERS_PER_TRIGGER);
 428         }
 429         kfree(trig->name);
 430         kfree(trig);
 431         iio_put();
 432 }
 433
 434 static struct device_type iio_trig_type = {
 435         .release = iio_trig_release,
 436 };
 437
 438 static void iio_trig_subirqmask(struct irq_data *d)
 439 {
 440         struct irq_chip *chip = irq_data_get_irq_chip(d);
 441         struct iio_trigger *trig
 442                 = container_of(chip,
 443                                struct iio_trigger, subirq_chip);
 444         trig->subirqs[d->irq - trig->subirq_base].enabled = false;
 445 }
 446
 447 static void iio_trig_subirqunmask(struct irq_data *d)
 448 {
 449         struct irq_chip *chip = irq_data_get_irq_chip(d);
 450         struct iio_trigger *trig
 451                 = container_of(chip,
 452                                struct iio_trigger, subirq_chip);
 453         trig->subirqs[d->irq - trig->subirq_base].enabled = true;
 454 }
 455
 456 struct iio_trigger *iio_allocate_trigger(const char *fmt, ...)
 457 {
 458         va_list vargs;
 459         struct iio_trigger *trig;
 460         trig = kzalloc(sizeof *trig, GFP_KERNEL);
 461         if (trig) {
 462                 int i;
 463                 trig->dev.type = &iio_trig_type;
 464                 trig->dev.bus = &iio_bus_type;
 465                 device_initialize(&trig->dev);
 466                 dev_set_drvdata(&trig->dev, (void *)trig);
 467
 468                 mutex_init(&trig->pool_lock);
 469                 trig->subirq_base
 470                         = irq_alloc_descs(-1, 0,
 471                                           CONFIG_IIO_CONSUMERS_PER_TRIGGER,
 472                                           0);
 473                 if (trig->subirq_base < 0) {
 474                         kfree(trig);
 475                         return NULL;
 476                 }
 477                 va_start(vargs, fmt);
 478                 trig->name = kvasprintf(GFP_KERNEL, fmt, vargs);
 479                 va_end(vargs);
 480                 if (trig->name == NULL) {
 481                         irq_free_descs(trig->subirq_base,
 482                                        CONFIG_IIO_CONSUMERS_PER_TRIGGER);
 483                         kfree(trig);
 484                         return NULL;
 485                 }
 486                 trig->subirq_chip.name = trig->name;
 487                 trig->subirq_chip.irq_mask = &iio_trig_subirqmask;
 488                 trig->subirq_chip.irq_unmask = &iio_trig_subirqunmask;
 489                 for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
 490                         irq_set_chip(trig->subirq_base + i,
 491                                      &trig->subirq_chip);
 492                         irq_set_handler(trig->subirq_base + i,
 493                                         &handle_simple_irq);
 494                         irq_modify_status(trig->subirq_base + i,
 495                                           IRQ_NOREQUEST | IRQ_NOAUTOEN,
 496                                           IRQ_NOPROBE);
 497                 }
 498                 iio_get();
 499                 get_device(&trig->dev);
 500         }
 501         return trig;
 502 }
 503 EXPORT_SYMBOL(iio_allocate_trigger);
 504
 505 void iio_free_trigger(struct iio_trigger *trig)
 506 {
 507         if (trig)
 508                 put_device(&trig->dev);
 509 }
 510 EXPORT_SYMBOL(iio_free_trigger);
 511
 512 int iio_device_register_trigger_consumer(struct iio_dev *dev_info)
 513 {
 514         return sysfs_create_group(&dev_info->dev.kobj,
 515                                   &iio_trigger_consumer_attr_group);
 516 }
 517
 518 void iio_device_unregister_trigger_consumer(struct iio_dev *dev_info)
 519 {
 520         /* Clean up and associated but not attached triggers references */
 521         if (dev_info->trig)
 522                 iio_put_trigger(dev_info->trig);
 523         sysfs_remove_group(&dev_info->dev.kobj,
 524                            &iio_trigger_consumer_attr_group);
 525 }
 526
 527 int iio_triggered_ring_postenable(struct iio_dev *indio_dev)
 528 {
 529         return indio_dev->trig
 530                 ? iio_trigger_attach_poll_func(indio_dev->trig,
 531                                                indio_dev->pollfunc)
 532                 : 0;
 533 }
 534 EXPORT_SYMBOL(iio_triggered_ring_postenable);
 535
 536 int iio_triggered_ring_predisable(struct iio_dev *indio_dev)
 537 {
 538         return indio_dev->trig
 539                 ? iio_trigger_dettach_poll_func(indio_dev->trig,
 540                                                 indio_dev->pollfunc)
 541                 : 0;
 542 }
 543 EXPORT_SYMBOL(iio_triggered_ring_predisable);