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_IDA(iio_trigger_ida);
  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 int iio_trigger_register(struct iio_trigger *trig_info)
  75 {
  76         int ret;
  77
  78         trig_info->id = ida_simple_get(&iio_trigger_ida, 0, 0, GFP_KERNEL);
  79         if (trig_info->id < 0) {
  80                 ret = trig_info->id;
  81                 goto error_ret;
  82         }
  83         /* Set the name used for the sysfs directory etc */
  84         dev_set_name(&trig_info->dev, "trigger%ld",
  85                      (unsigned long) trig_info->id);
  86
  87         ret = device_add(&trig_info->dev);
  88         if (ret)
  89                 goto error_unregister_id;
  90
  91         ret = iio_trigger_register_sysfs(trig_info);
  92         if (ret)
  93                 goto error_device_del;
  94
  95         /* Add to list of available triggers held by the IIO core */
  96         mutex_lock(&iio_trigger_list_lock);
  97         list_add_tail(&trig_info->list, &iio_trigger_list);
  98         mutex_unlock(&iio_trigger_list_lock);
  99
 100         return 0;
 101
 102 error_device_del:
 103         device_del(&trig_info->dev);
 104 error_unregister_id:
 105         ida_simple_remove(&iio_trigger_ida, trig_info->id);
 106 error_ret:
 107         return ret;
 108 }
 109 EXPORT_SYMBOL(iio_trigger_register);
 110
 111 void iio_trigger_unregister(struct iio_trigger *trig_info)
 112 {
 113         mutex_lock(&iio_trigger_list_lock);
 114         list_del(&trig_info->list);
 115         mutex_unlock(&iio_trigger_list_lock);
 116
 117         iio_trigger_unregister_sysfs(trig_info);
 118         ida_simple_remove(&iio_trigger_ida, trig_info->id);
 119         /* Possible issue in here */
 120         device_unregister(&trig_info->dev);
 121 }
 122 EXPORT_SYMBOL(iio_trigger_unregister);
 123
 124 static struct iio_trigger *iio_trigger_find_by_name(const char *name,
 125                                                     size_t len)
 126 {
 127         struct iio_trigger *trig = NULL, *iter;
 128
 129         mutex_lock(&iio_trigger_list_lock);
 130         list_for_each_entry(iter, &iio_trigger_list, list)
 131                 if (sysfs_streq(iter->name, name)) {
 132                         trig = iter;
 133                         break;
 134                 }
 135         mutex_unlock(&iio_trigger_list_lock);
 136
 137         return trig;
 138 }
 139
 140 void iio_trigger_poll(struct iio_trigger *trig, s64 time)
 141 {
 142         int i;
 143         if (!trig->use_count)
 144                 for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++)
 145                         if (trig->subirqs[i].enabled) {
 146                                 trig->use_count++;
 147                                 generic_handle_irq(trig->subirq_base + i);
 148                         }
 149 }
 150 EXPORT_SYMBOL(iio_trigger_poll);
 151
 152 irqreturn_t iio_trigger_generic_data_rdy_poll(int irq, void *private)
 153 {
 154         iio_trigger_poll(private, iio_get_time_ns());
 155         return IRQ_HANDLED;
 156 }
 157 EXPORT_SYMBOL(iio_trigger_generic_data_rdy_poll);
 158
 159 void iio_trigger_poll_chained(struct iio_trigger *trig, s64 time)
 160 {
 161         int i;
 162         if (!trig->use_count) {
 163                 for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++)
 164                         if (trig->subirqs[i].enabled) {
 165                                 trig->use_count++;
 166                                 handle_nested_irq(trig->subirq_base + i);
 167                         }
 168         }
 169 }
 170 EXPORT_SYMBOL(iio_trigger_poll_chained);
 171
 172 void iio_trigger_notify_done(struct iio_trigger *trig)
 173 {
 174         trig->use_count--;
 175         if (trig->use_count == 0 && trig->ops && trig->ops->try_reenable)
 176                 if (trig->ops->try_reenable(trig)) {
 177                         /* Missed and interrupt so launch new poll now */
 178                         iio_trigger_poll(trig, 0);
 179                 }
 180 }
 181 EXPORT_SYMBOL(iio_trigger_notify_done);
 182
 183 /* Trigger Consumer related functions */
 184 static int iio_trigger_get_irq(struct iio_trigger *trig)
 185 {
 186         int ret;
 187         mutex_lock(&trig->pool_lock);
 188         ret = bitmap_find_free_region(trig->pool,
 189                                       CONFIG_IIO_CONSUMERS_PER_TRIGGER,
 190                                       ilog2(1));
 191         mutex_unlock(&trig->pool_lock);
 192         if (ret >= 0)
 193                 ret += trig->subirq_base;
 194
 195         return ret;
 196 }
 197
 198 static void iio_trigger_put_irq(struct iio_trigger *trig, int irq)
 199 {
 200         mutex_lock(&trig->pool_lock);
 201         clear_bit(irq - trig->subirq_base, trig->pool);
 202         mutex_unlock(&trig->pool_lock);
 203 }
 204
 205 /* Complexity in here.  With certain triggers (datardy) an acknowledgement
 206  * may be needed if the pollfuncs do not include the data read for the
 207  * triggering device.
 208  * This is not currently handled.  Alternative of not enabling trigger unless
 209  * the relevant function is in there may be the best option.
 210  */
 211 /* Worth protecting against double additions?*/
 212 static int iio_trigger_attach_poll_func(struct iio_trigger *trig,
 213                                         struct iio_poll_func *pf)
 214 {
 215         int ret = 0;
 216         bool notinuse
 217                 = bitmap_empty(trig->pool, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
 218
 219         /* Prevent the module being removed whilst attached to a trigger */
 220         __module_get(pf->indio_dev->info->driver_module);
 221         pf->irq = iio_trigger_get_irq(trig);
 222         ret = request_threaded_irq(pf->irq, pf->h, pf->thread,
 223                                    pf->type, pf->name,
 224                                    pf);
 225         if (trig->ops && trig->ops->set_trigger_state && notinuse)
 226                 ret = trig->ops->set_trigger_state(trig, true);
 227
 228         return ret;
 229 }
 230
 231 static int iio_trigger_dettach_poll_func(struct iio_trigger *trig,
 232                                          struct iio_poll_func *pf)
 233 {
 234         int ret = 0;
 235         bool no_other_users
 236                 = (bitmap_weight(trig->pool,
 237                                  CONFIG_IIO_CONSUMERS_PER_TRIGGER)
 238                    == 1);
 239         if (trig->ops && trig->ops->set_trigger_state && no_other_users) {
 240                 ret = trig->ops->set_trigger_state(trig, false);
 241                 if (ret)
 242                         goto error_ret;
 243         }
 244         iio_trigger_put_irq(trig, pf->irq);
 245         free_irq(pf->irq, pf);
 246         module_put(pf->indio_dev->info->driver_module);
 247
 248 error_ret:
 249         return ret;
 250 }
 251
 252 irqreturn_t iio_pollfunc_store_time(int irq, void *p)
 253 {
 254         struct iio_poll_func *pf = p;
 255         pf->timestamp = iio_get_time_ns();
 256         return IRQ_WAKE_THREAD;
 257 }
 258 EXPORT_SYMBOL(iio_pollfunc_store_time);
 259
 260 struct iio_poll_func
 261 *iio_alloc_pollfunc(irqreturn_t (*h)(int irq, void *p),
 262                     irqreturn_t (*thread)(int irq, void *p),
 263                     int type,
 264                     struct iio_dev *indio_dev,
 265                     const char *fmt,
 266                     ...)
 267 {
 268         va_list vargs;
 269         struct iio_poll_func *pf;
 270
 271         pf = kmalloc(sizeof *pf, GFP_KERNEL);
 272         if (pf == NULL)
 273                 return NULL;
 274         va_start(vargs, fmt);
 275         pf->name = kvasprintf(GFP_KERNEL, fmt, vargs);
 276         va_end(vargs);
 277         if (pf->name == NULL) {
 278                 kfree(pf);
 279                 return NULL;
 280         }
 281         pf->h = h;
 282         pf->thread = thread;
 283         pf->type = type;
 284         pf->indio_dev = indio_dev;
 285
 286         return pf;
 287 }
 288 EXPORT_SYMBOL_GPL(iio_alloc_pollfunc);
 289
 290 void iio_dealloc_pollfunc(struct iio_poll_func *pf)
 291 {
 292         kfree(pf->name);
 293         kfree(pf);
 294 }
 295 EXPORT_SYMBOL_GPL(iio_dealloc_pollfunc);
 296
 297 /**
 298  * iio_trigger_read_currrent() - trigger consumer sysfs query which trigger
 299  *
 300  * For trigger consumers the current_trigger interface allows the trigger
 301  * used by the device to be queried.
 302  **/
 303 static ssize_t iio_trigger_read_current(struct device *dev,
 304                                         struct device_attribute *attr,
 305                                         char *buf)
 306 {
 307         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 308
 309         if (indio_dev->trig)
 310                 return sprintf(buf, "%s\n", indio_dev->trig->name);
 311         return 0;
 312 }
 313
 314 /**
 315  * iio_trigger_write_current() trigger consumer sysfs set current trigger
 316  *
 317  * For trigger consumers the current_trigger interface allows the trigger
 318  * used for this device to be specified at run time based on the triggers
 319  * name.
 320  **/
 321 static ssize_t iio_trigger_write_current(struct device *dev,
 322                                          struct device_attribute *attr,
 323                                          const char *buf,
 324                                          size_t len)
 325 {
 326         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 327         struct iio_trigger *oldtrig = indio_dev->trig;
 328         struct iio_trigger *trig;
 329         int ret;
 330
 331         mutex_lock(&indio_dev->mlock);
 332         if (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED) {
 333                 mutex_unlock(&indio_dev->mlock);
 334                 return -EBUSY;
 335         }
 336         mutex_unlock(&indio_dev->mlock);
 337
 338         trig = iio_trigger_find_by_name(buf, len);
 339
 340         if (trig && indio_dev->info->validate_trigger) {
 341                 ret = indio_dev->info->validate_trigger(indio_dev, trig);
 342                 if (ret)
 343                         return ret;
 344         }
 345
 346         if (trig && trig->ops && trig->ops->validate_device) {
 347                 ret = trig->ops->validate_device(trig, indio_dev);
 348                 if (ret)
 349                         return ret;
 350         }
 351
 352         indio_dev->trig = trig;
 353
 354         if (oldtrig && indio_dev->trig != oldtrig)
 355                 iio_put_trigger(oldtrig);
 356         if (indio_dev->trig)
 357                 iio_get_trigger(indio_dev->trig);
 358
 359         return len;
 360 }
 361
 362 static DEVICE_ATTR(current_trigger, S_IRUGO | S_IWUSR,
 363                    iio_trigger_read_current,
 364                    iio_trigger_write_current);
 365
 366 static struct attribute *iio_trigger_consumer_attrs[] = {
 367         &dev_attr_current_trigger.attr,
 368         NULL,
 369 };
 370
 371 static const struct attribute_group iio_trigger_consumer_attr_group = {
 372         .name = "trigger",
 373         .attrs = iio_trigger_consumer_attrs,
 374 };
 375
 376 static void iio_trig_release(struct device *device)
 377 {
 378         struct iio_trigger *trig = to_iio_trigger(device);
 379         int i;
 380
 381         if (trig->subirq_base) {
 382                 for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
 383                         irq_modify_status(trig->subirq_base + i,
 384                                           IRQ_NOAUTOEN,
 385                                           IRQ_NOREQUEST | IRQ_NOPROBE);
 386                         irq_set_chip(trig->subirq_base + i,
 387                                      NULL);
 388                         irq_set_handler(trig->subirq_base + i,
 389                                         NULL);
 390                 }
 391
 392                 irq_free_descs(trig->subirq_base,
 393                                CONFIG_IIO_CONSUMERS_PER_TRIGGER);
 394         }
 395         kfree(trig->name);
 396         kfree(trig);
 397 }
 398
 399 static struct device_type iio_trig_type = {
 400         .release = iio_trig_release,
 401 };
 402
 403 static void iio_trig_subirqmask(struct irq_data *d)
 404 {
 405         struct irq_chip *chip = irq_data_get_irq_chip(d);
 406         struct iio_trigger *trig
 407                 = container_of(chip,
 408                                struct iio_trigger, subirq_chip);
 409         trig->subirqs[d->irq - trig->subirq_base].enabled = false;
 410 }
 411
 412 static void iio_trig_subirqunmask(struct irq_data *d)
 413 {
 414         struct irq_chip *chip = irq_data_get_irq_chip(d);
 415         struct iio_trigger *trig
 416                 = container_of(chip,
 417                                struct iio_trigger, subirq_chip);
 418         trig->subirqs[d->irq - trig->subirq_base].enabled = true;
 419 }
 420
 421 struct iio_trigger *iio_allocate_trigger(const char *fmt, ...)
 422 {
 423         va_list vargs;
 424         struct iio_trigger *trig;
 425         trig = kzalloc(sizeof *trig, GFP_KERNEL);
 426         if (trig) {
 427                 int i;
 428                 trig->dev.type = &iio_trig_type;
 429                 trig->dev.bus = &iio_bus_type;
 430                 device_initialize(&trig->dev);
 431                 dev_set_drvdata(&trig->dev, (void *)trig);
 432
 433                 mutex_init(&trig->pool_lock);
 434                 trig->subirq_base
 435                         = irq_alloc_descs(-1, 0,
 436                                           CONFIG_IIO_CONSUMERS_PER_TRIGGER,
 437                                           0);
 438                 if (trig->subirq_base < 0) {
 439                         kfree(trig);
 440                         return NULL;
 441                 }
 442                 va_start(vargs, fmt);
 443                 trig->name = kvasprintf(GFP_KERNEL, fmt, vargs);
 444                 va_end(vargs);
 445                 if (trig->name == NULL) {
 446                         irq_free_descs(trig->subirq_base,
 447                                        CONFIG_IIO_CONSUMERS_PER_TRIGGER);
 448                         kfree(trig);
 449                         return NULL;
 450                 }
 451                 trig->subirq_chip.name = trig->name;
 452                 trig->subirq_chip.irq_mask = &iio_trig_subirqmask;
 453                 trig->subirq_chip.irq_unmask = &iio_trig_subirqunmask;
 454                 for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
 455                         irq_set_chip(trig->subirq_base + i,
 456                                      &trig->subirq_chip);
 457                         irq_set_handler(trig->subirq_base + i,
 458                                         &handle_simple_irq);
 459                         irq_modify_status(trig->subirq_base + i,
 460                                           IRQ_NOREQUEST | IRQ_NOAUTOEN,
 461                                           IRQ_NOPROBE);
 462                 }
 463                 get_device(&trig->dev);
 464         }
 465         return trig;
 466 }
 467 EXPORT_SYMBOL(iio_allocate_trigger);
 468
 469 void iio_free_trigger(struct iio_trigger *trig)
 470 {
 471         if (trig)
 472                 put_device(&trig->dev);
 473 }
 474 EXPORT_SYMBOL(iio_free_trigger);
 475
 476 int iio_device_register_trigger_consumer(struct iio_dev *indio_dev)
 477 {
 478         indio_dev->groups[indio_dev->groupcounter++] =
 479                 &iio_trigger_consumer_attr_group;
 480
 481         return 0;
 482 }
 483
 484 void iio_device_unregister_trigger_consumer(struct iio_dev *indio_dev)
 485 {
 486         /* Clean up and associated but not attached triggers references */
 487         if (indio_dev->trig)
 488                 iio_put_trigger(indio_dev->trig);
 489 }
 490
 491 int iio_triggered_buffer_postenable(struct iio_dev *indio_dev)
 492 {
 493         return indio_dev->trig
 494                 ? iio_trigger_attach_poll_func(indio_dev->trig,
 495                                                indio_dev->pollfunc)
 496                 : 0;
 497 }
 498 EXPORT_SYMBOL(iio_triggered_buffer_postenable);
 499
 500 int iio_triggered_buffer_predisable(struct iio_dev *indio_dev)
 501 {
 502         return indio_dev->trig
 503                 ? iio_trigger_dettach_poll_func(indio_dev->trig,
 504                                                 indio_dev->pollfunc)
 505                 : 0;
 506 }
 507 EXPORT_SYMBOL(iio_triggered_buffer_predisable);