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/module.h>
  12 #include <linux/idr.h>
  13 #include <linux/err.h>
  14 #include <linux/device.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/list.h>
  17 #include <linux/slab.h>
  18
  19 #include "iio.h"
  20 #include "trigger.h"
  21 #include "iio_core.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 }
 185 EXPORT_SYMBOL(iio_trigger_poll);
 186
 187 irqreturn_t iio_trigger_generic_data_rdy_poll(int irq, void *private)
 188 {
 189         iio_trigger_poll(private, iio_get_time_ns());
 190         return IRQ_HANDLED;
 191 }
 192 EXPORT_SYMBOL(iio_trigger_generic_data_rdy_poll);
 193
 194 void iio_trigger_poll_chained(struct iio_trigger *trig, s64 time)
 195 {
 196         int i;
 197         if (!trig->use_count) {
 198                 for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++)
 199                         if (trig->subirqs[i].enabled) {
 200                                 trig->use_count++;
 201                                 handle_nested_irq(trig->subirq_base + i);
 202                         }
 203         }
 204 }
 205 EXPORT_SYMBOL(iio_trigger_poll_chained);
 206
 207 void iio_trigger_notify_done(struct iio_trigger *trig)
 208 {
 209         trig->use_count--;
 210         if (trig->use_count == 0 && trig->ops && trig->ops->try_reenable)
 211                 if (trig->ops->try_reenable(trig)) {
 212                         /* Missed and interrupt so launch new poll now */
 213                         iio_trigger_poll(trig, 0);
 214                 }
 215 }
 216 EXPORT_SYMBOL(iio_trigger_notify_done);
 217
 218 /* Trigger Consumer related functions */
 219
 220 /* Complexity in here.  With certain triggers (datardy) an acknowledgement
 221  * may be needed if the pollfuncs do not include the data read for the
 222  * triggering device.
 223  * This is not currently handled.  Alternative of not enabling trigger unless
 224  * the relevant function is in there may be the best option.
 225  */
 226 /* Worth protecting against double additions?*/
 227 int iio_trigger_attach_poll_func(struct iio_trigger *trig,
 228                                  struct iio_poll_func *pf)
 229 {
 230         int ret = 0;
 231         bool notinuse
 232                 = bitmap_empty(trig->pool, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
 233
 234         pf->irq = iio_trigger_get_irq(trig);
 235         ret = request_threaded_irq(pf->irq, pf->h, pf->thread,
 236                                    pf->type, pf->name,
 237                                    pf);
 238         if (trig->ops && trig->ops->set_trigger_state && notinuse)
 239                 ret = trig->ops->set_trigger_state(trig, true);
 240
 241         return ret;
 242 }
 243 EXPORT_SYMBOL(iio_trigger_attach_poll_func);
 244
 245 int iio_trigger_dettach_poll_func(struct iio_trigger *trig,
 246                                   struct iio_poll_func *pf)
 247 {
 248         int ret = 0;
 249         bool no_other_users
 250                 = (bitmap_weight(trig->pool,
 251                                  CONFIG_IIO_CONSUMERS_PER_TRIGGER)
 252                    == 1);
 253         if (trig->ops && trig->ops->set_trigger_state && no_other_users) {
 254                 ret = trig->ops->set_trigger_state(trig, false);
 255                 if (ret)
 256                         goto error_ret;
 257         }
 258         iio_trigger_put_irq(trig, pf->irq);
 259         free_irq(pf->irq, pf);
 260
 261 error_ret:
 262         return ret;
 263 }
 264 EXPORT_SYMBOL(iio_trigger_dettach_poll_func);
 265
 266 irqreturn_t iio_pollfunc_store_time(int irq, void *p)
 267 {
 268         struct iio_poll_func *pf = p;
 269         pf->timestamp = iio_get_time_ns();
 270         return IRQ_WAKE_THREAD;
 271 }
 272 EXPORT_SYMBOL(iio_pollfunc_store_time);
 273
 274 struct iio_poll_func
 275 *iio_alloc_pollfunc(irqreturn_t (*h)(int irq, void *p),
 276                     irqreturn_t (*thread)(int irq, void *p),
 277                     int type,
 278                     void *private,
 279                     const char *fmt,
 280                     ...)
 281 {
 282         va_list vargs;
 283         struct iio_poll_func *pf;
 284
 285         pf = kmalloc(sizeof *pf, GFP_KERNEL);
 286         if (pf == NULL)
 287                 return NULL;
 288         va_start(vargs, fmt);
 289         pf->name = kvasprintf(GFP_KERNEL, fmt, vargs);
 290         va_end(vargs);
 291         if (pf->name == NULL) {
 292                 kfree(pf);
 293                 return NULL;
 294         }
 295         pf->h = h;
 296         pf->thread = thread;
 297         pf->type = type;
 298         pf->private_data = private;
 299
 300         return pf;
 301 }
 302 EXPORT_SYMBOL_GPL(iio_alloc_pollfunc);
 303
 304 void iio_dealloc_pollfunc(struct iio_poll_func *pf)
 305 {
 306         kfree(pf->name);
 307         kfree(pf);
 308 }
 309 EXPORT_SYMBOL_GPL(iio_dealloc_pollfunc);
 310
 311 /**
 312  * iio_trigger_read_currrent() - trigger consumer sysfs query which trigger
 313  *
 314  * For trigger consumers the current_trigger interface allows the trigger
 315  * used by the device to be queried.
 316  **/
 317 static ssize_t iio_trigger_read_current(struct device *dev,
 318                                         struct device_attribute *attr,
 319                                         char *buf)
 320 {
 321         struct iio_dev *dev_info = dev_get_drvdata(dev);
 322         int len = 0;
 323         if (dev_info->trig)
 324                 len = sprintf(buf,
 325                               "%s\n",
 326                               dev_info->trig->name);
 327         return len;
 328 }
 329
 330 /**
 331  * iio_trigger_write_current() trigger consumer sysfs set current trigger
 332  *
 333  * For trigger consumers the current_trigger interface allows the trigger
 334  * used for this device to be specified at run time based on the triggers
 335  * name.
 336  **/
 337 static ssize_t iio_trigger_write_current(struct device *dev,
 338                                          struct device_attribute *attr,
 339                                          const char *buf,
 340                                          size_t len)
 341 {
 342         struct iio_dev *dev_info = dev_get_drvdata(dev);
 343         struct iio_trigger *oldtrig = dev_info->trig;
 344         struct iio_trigger *trig;
 345         int ret;
 346
 347         mutex_lock(&dev_info->mlock);
 348         if (dev_info->currentmode == INDIO_RING_TRIGGERED) {
 349                 mutex_unlock(&dev_info->mlock);
 350                 return -EBUSY;
 351         }
 352         mutex_unlock(&dev_info->mlock);
 353
 354         trig = iio_trigger_find_by_name(buf, len);
 355
 356         if (trig && dev_info->info->validate_trigger) {
 357                 ret = dev_info->info->validate_trigger(dev_info, trig);
 358                 if (ret)
 359                         return ret;
 360         }
 361
 362         if (trig && trig->ops && trig->ops->validate_device) {
 363                 ret = trig->ops->validate_device(trig, dev_info);
 364                 if (ret)
 365                         return ret;
 366         }
 367
 368         dev_info->trig = trig;
 369
 370         if (oldtrig && dev_info->trig != oldtrig)
 371                 iio_put_trigger(oldtrig);
 372         if (dev_info->trig)
 373                 iio_get_trigger(dev_info->trig);
 374
 375         return len;
 376 }
 377
 378 static DEVICE_ATTR(current_trigger, S_IRUGO | S_IWUSR,
 379                    iio_trigger_read_current,
 380                    iio_trigger_write_current);
 381
 382 static struct attribute *iio_trigger_consumer_attrs[] = {
 383         &dev_attr_current_trigger.attr,
 384         NULL,
 385 };
 386
 387 static const struct attribute_group iio_trigger_consumer_attr_group = {
 388         .name = "trigger",
 389         .attrs = iio_trigger_consumer_attrs,
 390 };
 391
 392 static void iio_trig_release(struct device *device)
 393 {
 394         struct iio_trigger *trig = to_iio_trigger(device);
 395         int i;
 396
 397         if (trig->subirq_base) {
 398                 for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
 399                         irq_modify_status(trig->subirq_base + i,
 400                                           IRQ_NOAUTOEN,
 401                                           IRQ_NOREQUEST | IRQ_NOPROBE);
 402                         irq_set_chip(trig->subirq_base + i,
 403                                      NULL);
 404                         irq_set_handler(trig->subirq_base + i,
 405                                         NULL);
 406                 }
 407
 408                 irq_free_descs(trig->subirq_base,
 409                                CONFIG_IIO_CONSUMERS_PER_TRIGGER);
 410         }
 411         kfree(trig->name);
 412         kfree(trig);
 413         iio_put();
 414 }
 415
 416 static struct device_type iio_trig_type = {
 417         .release = iio_trig_release,
 418 };
 419
 420 static void iio_trig_subirqmask(struct irq_data *d)
 421 {
 422         struct irq_chip *chip = irq_data_get_irq_chip(d);
 423         struct iio_trigger *trig
 424                 = container_of(chip,
 425                                struct iio_trigger, subirq_chip);
 426         trig->subirqs[d->irq - trig->subirq_base].enabled = false;
 427 }
 428
 429 static void iio_trig_subirqunmask(struct irq_data *d)
 430 {
 431         struct irq_chip *chip = irq_data_get_irq_chip(d);
 432         struct iio_trigger *trig
 433                 = container_of(chip,
 434                                struct iio_trigger, subirq_chip);
 435         trig->subirqs[d->irq - trig->subirq_base].enabled = true;
 436 }
 437
 438 struct iio_trigger *iio_allocate_trigger(const char *fmt, ...)
 439 {
 440         va_list vargs;
 441         struct iio_trigger *trig;
 442         trig = kzalloc(sizeof *trig, GFP_KERNEL);
 443         if (trig) {
 444                 int i;
 445                 trig->dev.type = &iio_trig_type;
 446                 trig->dev.bus = &iio_bus_type;
 447                 device_initialize(&trig->dev);
 448                 dev_set_drvdata(&trig->dev, (void *)trig);
 449
 450                 mutex_init(&trig->pool_lock);
 451                 trig->subirq_base
 452                         = irq_alloc_descs(-1, 0,
 453                                           CONFIG_IIO_CONSUMERS_PER_TRIGGER,
 454                                           0);
 455                 if (trig->subirq_base < 0) {
 456                         kfree(trig);
 457                         return NULL;
 458                 }
 459                 va_start(vargs, fmt);
 460                 trig->name = kvasprintf(GFP_KERNEL, fmt, vargs);
 461                 va_end(vargs);
 462                 if (trig->name == NULL) {
 463                         irq_free_descs(trig->subirq_base,
 464                                        CONFIG_IIO_CONSUMERS_PER_TRIGGER);
 465                         kfree(trig);
 466                         return NULL;
 467                 }
 468                 trig->subirq_chip.name = trig->name;
 469                 trig->subirq_chip.irq_mask = &iio_trig_subirqmask;
 470                 trig->subirq_chip.irq_unmask = &iio_trig_subirqunmask;
 471                 for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
 472                         irq_set_chip(trig->subirq_base + i,
 473                                      &trig->subirq_chip);
 474                         irq_set_handler(trig->subirq_base + i,
 475                                         &handle_simple_irq);
 476                         irq_modify_status(trig->subirq_base + i,
 477                                           IRQ_NOREQUEST | IRQ_NOAUTOEN,
 478                                           IRQ_NOPROBE);
 479                 }
 480                 iio_get();
 481         }
 482         return trig;
 483 }
 484 EXPORT_SYMBOL(iio_allocate_trigger);
 485
 486 void iio_free_trigger(struct iio_trigger *trig)
 487 {
 488         if (trig)
 489                 put_device(&trig->dev);
 490 }
 491 EXPORT_SYMBOL(iio_free_trigger);
 492
 493 int iio_device_register_trigger_consumer(struct iio_dev *dev_info)
 494 {
 495         int ret;
 496         ret = sysfs_create_group(&dev_info->dev.kobj,
 497                                  &iio_trigger_consumer_attr_group);
 498         return ret;
 499 }
 500 EXPORT_SYMBOL(iio_device_register_trigger_consumer);
 501
 502 int iio_device_unregister_trigger_consumer(struct iio_dev *dev_info)
 503 {
 504         sysfs_remove_group(&dev_info->dev.kobj,
 505                            &iio_trigger_consumer_attr_group);
 506         return 0;
 507 }
 508 EXPORT_SYMBOL(iio_device_unregister_trigger_consumer);
 509
 510 int iio_triggered_ring_postenable(struct iio_dev *indio_dev)
 511 {
 512         return indio_dev->trig
 513                 ? iio_trigger_attach_poll_func(indio_dev->trig,
 514                                                indio_dev->pollfunc)
 515                 : 0;
 516 }
 517 EXPORT_SYMBOL(iio_triggered_ring_postenable);
 518
 519 int iio_triggered_ring_predisable(struct iio_dev *indio_dev)
 520 {
 521         return indio_dev->trig
 522                 ? iio_trigger_dettach_poll_func(indio_dev->trig,
 523                                                 indio_dev->pollfunc)
 524                 : 0;
 525 }
 526 EXPORT_SYMBOL(iio_triggered_ring_predisable);