drivers/iio/inkern.c

   1 /* The industrial I/O core in kernel channel mapping
   2  *
   3  * Copyright (c) 2011 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 #include <linux/err.h>
  10 #include <linux/export.h>
  11 #include <linux/slab.h>
  12 #include <linux/mutex.h>
  13 #include <linux/of.h>
  14
  15 #include <linux/iio/iio.h>
  16 #include "iio_core.h"
  17 #include <linux/iio/machine.h>
  18 #include <linux/iio/driver.h>
  19 #include <linux/iio/consumer.h>
  20
  21 struct iio_map_internal {
  22         struct iio_dev *indio_dev;
  23         struct iio_map *map;
  24         struct list_head l;
  25 };
  26
  27 static LIST_HEAD(iio_map_list);
  28 static DEFINE_MUTEX(iio_map_list_lock);
  29
  30 int iio_map_array_register(struct iio_dev *indio_dev, struct iio_map *maps)
  31 {
  32         int i = 0, ret = 0;
  33         struct iio_map_internal *mapi;
  34
  35         if (maps == NULL)
  36                 return 0;
  37
  38         mutex_lock(&iio_map_list_lock);
  39         while (maps[i].consumer_dev_name != NULL) {
  40                 mapi = kzalloc(sizeof(*mapi), GFP_KERNEL);
  41                 if (mapi == NULL) {
  42                         ret = -ENOMEM;
  43                         goto error_ret;
  44                 }
  45                 mapi->map = &maps[i];
  46                 mapi->indio_dev = indio_dev;
  47                 list_add_tail(&mapi->l, &iio_map_list);
  48                 i++;
  49         }
  50 error_ret:
  51         mutex_unlock(&iio_map_list_lock);
  52
  53         return ret;
  54 }
  55 EXPORT_SYMBOL_GPL(iio_map_array_register);
  56
  57
  58 /*
  59  * Remove all map entries associated with the given iio device
  60  */
  61 int iio_map_array_unregister(struct iio_dev *indio_dev)
  62 {
  63         int ret = -ENODEV;
  64         struct iio_map_internal *mapi, *next;
  65
  66         mutex_lock(&iio_map_list_lock);
  67         list_for_each_entry_safe(mapi, next, &iio_map_list, l) {
  68                 if (indio_dev == mapi->indio_dev) {
  69                         list_del(&mapi->l);
  70                         kfree(mapi);
  71                         ret = 0;
  72                 }
  73         }
  74         mutex_unlock(&iio_map_list_lock);
  75         return ret;
  76 }
  77 EXPORT_SYMBOL_GPL(iio_map_array_unregister);
  78
  79 static const struct iio_chan_spec
  80 *iio_chan_spec_from_name(const struct iio_dev *indio_dev, const char *name)
  81 {
  82         int i;
  83         const struct iio_chan_spec *chan = NULL;
  84
  85         for (i = 0; i < indio_dev->num_channels; i++)
  86                 if (indio_dev->channels[i].datasheet_name &&
  87                     strcmp(name, indio_dev->channels[i].datasheet_name) == 0) {
  88                         chan = &indio_dev->channels[i];
  89                         break;
  90                 }
  91         return chan;
  92 }
  93
  94 #ifdef CONFIG_OF
  95
  96 static int iio_dev_node_match(struct device *dev, void *data)
  97 {
  98         return dev->of_node == data && dev->type == &iio_device_type;
  99 }
 100
 101 /**
 102  * __of_iio_simple_xlate - translate iiospec to the IIO channel index
 103  * @indio_dev:  pointer to the iio_dev structure
 104  * @iiospec:    IIO specifier as found in the device tree
 105  *
 106  * This is simple translation function, suitable for the most 1:1 mapped
 107  * channels in IIO chips. This function performs only one sanity check:
 108  * whether IIO index is less than num_channels (that is specified in the
 109  * iio_dev).
 110  */
 111 static int __of_iio_simple_xlate(struct iio_dev *indio_dev,
 112                                 const struct of_phandle_args *iiospec)
 113 {
 114         if (!iiospec->args_count)
 115                 return 0;
 116
 117         if (iiospec->args[0] >= indio_dev->num_channels) {
 118                 dev_err(&indio_dev->dev, "invalid channel index %u\n",
 119                         iiospec->args[0]);
 120                 return -EINVAL;
 121         }
 122
 123         return iiospec->args[0];
 124 }
 125
 126 static int __of_iio_channel_get(struct iio_channel *channel,
 127                                 struct device_node *np, int index)
 128 {
 129         struct device *idev;
 130         struct iio_dev *indio_dev;
 131         int err;
 132         struct of_phandle_args iiospec;
 133
 134         err = of_parse_phandle_with_args(np, "io-channels",
 135                                          "#io-channel-cells",
 136                                          index, &iiospec);
 137         if (err)
 138                 return err;
 139
 140         idev = bus_find_device(&iio_bus_type, NULL, iiospec.np,
 141                                iio_dev_node_match);
 142         of_node_put(iiospec.np);
 143         if (idev == NULL)
 144                 return -EPROBE_DEFER;
 145
 146         indio_dev = dev_to_iio_dev(idev);
 147         channel->indio_dev = indio_dev;
 148         if (indio_dev->info->of_xlate)
 149                 index = indio_dev->info->of_xlate(indio_dev, &iiospec);
 150         else
 151                 index = __of_iio_simple_xlate(indio_dev, &iiospec);
 152         if (index < 0)
 153                 goto err_put;
 154         channel->channel = &indio_dev->channels[index];
 155
 156         return 0;
 157
 158 err_put:
 159         iio_device_put(indio_dev);
 160         return index;
 161 }
 162
 163 static struct iio_channel *of_iio_channel_get(struct device_node *np, int index)
 164 {
 165         struct iio_channel *channel;
 166         int err;
 167
 168         if (index < 0)
 169                 return ERR_PTR(-EINVAL);
 170
 171         channel = kzalloc(sizeof(*channel), GFP_KERNEL);
 172         if (channel == NULL)
 173                 return ERR_PTR(-ENOMEM);
 174
 175         err = __of_iio_channel_get(channel, np, index);
 176         if (err)
 177                 goto err_free_channel;
 178
 179         return channel;
 180
 181 err_free_channel:
 182         kfree(channel);
 183         return ERR_PTR(err);
 184 }
 185
 186 static struct iio_channel *of_iio_channel_get_by_name(struct device_node *np,
 187                                                       const char *name)
 188 {
 189         struct iio_channel *chan = NULL;
 190
 191         /* Walk up the tree of devices looking for a matching iio channel */
 192         while (np) {
 193                 int index = 0;
 194
 195                 /*
 196                  * For named iio channels, first look up the name in the
 197                  * "io-channel-names" property.  If it cannot be found, the
 198                  * index will be an error code, and of_iio_channel_get()
 199                  * will fail.
 200                  */
 201                 if (name)
 202                         index = of_property_match_string(np, "io-channel-names",
 203                                                          name);
 204                 chan = of_iio_channel_get(np, index);
 205                 if (!IS_ERR(chan) || PTR_ERR(chan) == -EPROBE_DEFER)
 206                         break;
 207                 else if (name && index >= 0) {
 208                         pr_err("ERROR: could not get IIO channel %pOF:%s(%i)\n",
 209                                 np, name ? name : "", index);
 210                         return NULL;
 211                 }
 212
 213                 /*
 214                  * No matching IIO channel found on this node.
 215                  * If the parent node has a "io-channel-ranges" property,
 216                  * then we can try one of its channels.
 217                  */
 218                 np = np->parent;
 219                 if (np && !of_get_property(np, "io-channel-ranges", NULL))
 220                         return NULL;
 221         }
 222
 223         return chan;
 224 }
 225
 226 static struct iio_channel *of_iio_channel_get_all(struct device *dev)
 227 {
 228         struct iio_channel *chans;
 229         int i, mapind, nummaps = 0;
 230         int ret;
 231
 232         do {
 233                 ret = of_parse_phandle_with_args(dev->of_node,
 234                                                  "io-channels",
 235                                                  "#io-channel-cells",
 236                                                  nummaps, NULL);
 237                 if (ret < 0)
 238                         break;
 239         } while (++nummaps);
 240
 241         if (nummaps == 0)       /* no error, return NULL to search map table */
 242                 return NULL;
 243
 244         /* NULL terminated array to save passing size */
 245         chans = kcalloc(nummaps + 1, sizeof(*chans), GFP_KERNEL);
 246         if (chans == NULL)
 247                 return ERR_PTR(-ENOMEM);
 248
 249         /* Search for OF matches */
 250         for (mapind = 0; mapind < nummaps; mapind++) {
 251                 ret = __of_iio_channel_get(&chans[mapind], dev->of_node,
 252                                            mapind);
 253                 if (ret)
 254                         goto error_free_chans;
 255         }
 256         return chans;
 257
 258 error_free_chans:
 259         for (i = 0; i < mapind; i++)
 260                 iio_device_put(chans[i].indio_dev);
 261         kfree(chans);
 262         return ERR_PTR(ret);
 263 }
 264
 265 #else /* CONFIG_OF */
 266
 267 static inline struct iio_channel *
 268 of_iio_channel_get_by_name(struct device_node *np, const char *name)
 269 {
 270         return NULL;
 271 }
 272
 273 static inline struct iio_channel *of_iio_channel_get_all(struct device *dev)
 274 {
 275         return NULL;
 276 }
 277
 278 #endif /* CONFIG_OF */
 279
 280 static struct iio_channel *iio_channel_get_sys(const char *name,
 281                                                const char *channel_name)
 282 {
 283         struct iio_map_internal *c_i = NULL, *c = NULL;
 284         struct iio_channel *channel;
 285         int err;
 286
 287         if (name == NULL && channel_name == NULL)
 288                 return ERR_PTR(-ENODEV);
 289
 290         /* first find matching entry the channel map */
 291         mutex_lock(&iio_map_list_lock);
 292         list_for_each_entry(c_i, &iio_map_list, l) {
 293                 if ((name && strcmp(name, c_i->map->consumer_dev_name) != 0) ||
 294                     (channel_name &&
 295                      strcmp(channel_name, c_i->map->consumer_channel) != 0))
 296                         continue;
 297                 c = c_i;
 298                 iio_device_get(c->indio_dev);
 299                 break;
 300         }
 301         mutex_unlock(&iio_map_list_lock);
 302         if (c == NULL)
 303                 return ERR_PTR(-ENODEV);
 304
 305         channel = kzalloc(sizeof(*channel), GFP_KERNEL);
 306         if (channel == NULL) {
 307                 err = -ENOMEM;
 308                 goto error_no_mem;
 309         }
 310
 311         channel->indio_dev = c->indio_dev;
 312
 313         if (c->map->adc_channel_label) {
 314                 channel->channel =
 315                         iio_chan_spec_from_name(channel->indio_dev,
 316                                                 c->map->adc_channel_label);
 317
 318                 if (channel->channel == NULL) {
 319                         err = -EINVAL;
 320                         goto error_no_chan;
 321                 }
 322         }
 323
 324         return channel;
 325
 326 error_no_chan:
 327         kfree(channel);
 328 error_no_mem:
 329         iio_device_put(c->indio_dev);
 330         return ERR_PTR(err);
 331 }
 332
 333 struct iio_channel *iio_channel_get(struct device *dev,
 334                                     const char *channel_name)
 335 {
 336         const char *name = dev ? dev_name(dev) : NULL;
 337         struct iio_channel *channel;
 338
 339         if (dev) {
 340                 channel = of_iio_channel_get_by_name(dev->of_node,
 341                                                      channel_name);
 342                 if (channel != NULL)
 343                         return channel;
 344         }
 345
 346         return iio_channel_get_sys(name, channel_name);
 347 }
 348 EXPORT_SYMBOL_GPL(iio_channel_get);
 349
 350 void iio_channel_release(struct iio_channel *channel)
 351 {
 352         if (!channel)
 353                 return;
 354         iio_device_put(channel->indio_dev);
 355         kfree(channel);
 356 }
 357 EXPORT_SYMBOL_GPL(iio_channel_release);
 358
 359 static void devm_iio_channel_free(struct device *dev, void *res)
 360 {
 361         struct iio_channel *channel = *(struct iio_channel **)res;
 362
 363         iio_channel_release(channel);
 364 }
 365
 366 static int devm_iio_channel_match(struct device *dev, void *res, void *data)
 367 {
 368         struct iio_channel **r = res;
 369
 370         if (!r || !*r) {
 371                 WARN_ON(!r || !*r);
 372                 return 0;
 373         }
 374
 375         return *r == data;
 376 }
 377
 378 struct iio_channel *devm_iio_channel_get(struct device *dev,
 379                                          const char *channel_name)
 380 {
 381         struct iio_channel **ptr, *channel;
 382
 383         ptr = devres_alloc(devm_iio_channel_free, sizeof(*ptr), GFP_KERNEL);
 384         if (!ptr)
 385                 return ERR_PTR(-ENOMEM);
 386
 387         channel = iio_channel_get(dev, channel_name);
 388         if (IS_ERR(channel)) {
 389                 devres_free(ptr);
 390                 return channel;
 391         }
 392
 393         *ptr = channel;
 394         devres_add(dev, ptr);
 395
 396         return channel;
 397 }
 398 EXPORT_SYMBOL_GPL(devm_iio_channel_get);
 399
 400 void devm_iio_channel_release(struct device *dev, struct iio_channel *channel)
 401 {
 402         WARN_ON(devres_release(dev, devm_iio_channel_free,
 403                                devm_iio_channel_match, channel));
 404 }
 405 EXPORT_SYMBOL_GPL(devm_iio_channel_release);
 406
 407 struct iio_channel *iio_channel_get_all(struct device *dev)
 408 {
 409         const char *name;
 410         struct iio_channel *chans;
 411         struct iio_map_internal *c = NULL;
 412         int nummaps = 0;
 413         int mapind = 0;
 414         int i, ret;
 415
 416         if (dev == NULL)
 417                 return ERR_PTR(-EINVAL);
 418
 419         chans = of_iio_channel_get_all(dev);
 420         if (chans)
 421                 return chans;
 422
 423         name = dev_name(dev);
 424
 425         mutex_lock(&iio_map_list_lock);
 426         /* first count the matching maps */
 427         list_for_each_entry(c, &iio_map_list, l)
 428                 if (name && strcmp(name, c->map->consumer_dev_name) != 0)
 429                         continue;
 430                 else
 431                         nummaps++;
 432
 433         if (nummaps == 0) {
 434                 ret = -ENODEV;
 435                 goto error_ret;
 436         }
 437
 438         /* NULL terminated array to save passing size */
 439         chans = kcalloc(nummaps + 1, sizeof(*chans), GFP_KERNEL);
 440         if (chans == NULL) {
 441                 ret = -ENOMEM;
 442                 goto error_ret;
 443         }
 444
 445         /* for each map fill in the chans element */
 446         list_for_each_entry(c, &iio_map_list, l) {
 447                 if (name && strcmp(name, c->map->consumer_dev_name) != 0)
 448                         continue;
 449                 chans[mapind].indio_dev = c->indio_dev;
 450                 chans[mapind].data = c->map->consumer_data;
 451                 chans[mapind].channel =
 452                         iio_chan_spec_from_name(chans[mapind].indio_dev,
 453                                                 c->map->adc_channel_label);
 454                 if (chans[mapind].channel == NULL) {
 455                         ret = -EINVAL;
 456                         goto error_free_chans;
 457                 }
 458                 iio_device_get(chans[mapind].indio_dev);
 459                 mapind++;
 460         }
 461         if (mapind == 0) {
 462                 ret = -ENODEV;
 463                 goto error_free_chans;
 464         }
 465         mutex_unlock(&iio_map_list_lock);
 466
 467         return chans;
 468
 469 error_free_chans:
 470         for (i = 0; i < nummaps; i++)
 471                 iio_device_put(chans[i].indio_dev);
 472         kfree(chans);
 473 error_ret:
 474         mutex_unlock(&iio_map_list_lock);
 475
 476         return ERR_PTR(ret);
 477 }
 478 EXPORT_SYMBOL_GPL(iio_channel_get_all);
 479
 480 void iio_channel_release_all(struct iio_channel *channels)
 481 {
 482         struct iio_channel *chan = &channels[0];
 483
 484         while (chan->indio_dev) {
 485                 iio_device_put(chan->indio_dev);
 486                 chan++;
 487         }
 488         kfree(channels);
 489 }
 490 EXPORT_SYMBOL_GPL(iio_channel_release_all);
 491
 492 static void devm_iio_channel_free_all(struct device *dev, void *res)
 493 {
 494         struct iio_channel *channels = *(struct iio_channel **)res;
 495
 496         iio_channel_release_all(channels);
 497 }
 498
 499 struct iio_channel *devm_iio_channel_get_all(struct device *dev)
 500 {
 501         struct iio_channel **ptr, *channels;
 502
 503         ptr = devres_alloc(devm_iio_channel_free_all, sizeof(*ptr), GFP_KERNEL);
 504         if (!ptr)
 505                 return ERR_PTR(-ENOMEM);
 506
 507         channels = iio_channel_get_all(dev);
 508         if (IS_ERR(channels)) {
 509                 devres_free(ptr);
 510                 return channels;
 511         }
 512
 513         *ptr = channels;
 514         devres_add(dev, ptr);
 515
 516         return channels;
 517 }
 518 EXPORT_SYMBOL_GPL(devm_iio_channel_get_all);
 519
 520 void devm_iio_channel_release_all(struct device *dev,
 521                                   struct iio_channel *channels)
 522 {
 523         WARN_ON(devres_release(dev, devm_iio_channel_free_all,
 524                                devm_iio_channel_match, channels));
 525 }
 526 EXPORT_SYMBOL_GPL(devm_iio_channel_release_all);
 527
 528 static int iio_channel_read(struct iio_channel *chan, int *val, int *val2,
 529         enum iio_chan_info_enum info)
 530 {
 531         int unused;
 532         int vals[INDIO_MAX_RAW_ELEMENTS];
 533         int ret;
 534         int val_len = 2;
 535
 536         if (val2 == NULL)
 537                 val2 = &unused;
 538
 539         if (!iio_channel_has_info(chan->channel, info))
 540                 return -EINVAL;
 541
 542         if (chan->indio_dev->info->read_raw_multi) {
 543                 ret = chan->indio_dev->info->read_raw_multi(chan->indio_dev,
 544                                         chan->channel, INDIO_MAX_RAW_ELEMENTS,
 545                                         vals, &val_len, info);
 546                 *val = vals[0];
 547                 *val2 = vals[1];
 548         } else
 549                 ret = chan->indio_dev->info->read_raw(chan->indio_dev,
 550                                         chan->channel, val, val2, info);
 551
 552         return ret;
 553 }
 554
 555 int iio_read_channel_raw(struct iio_channel *chan, int *val)
 556 {
 557         int ret;
 558
 559         mutex_lock(&chan->indio_dev->info_exist_lock);
 560         if (chan->indio_dev->info == NULL) {
 561                 ret = -ENODEV;
 562                 goto err_unlock;
 563         }
 564
 565         ret = iio_channel_read(chan, val, NULL, IIO_CHAN_INFO_RAW);
 566 err_unlock:
 567         mutex_unlock(&chan->indio_dev->info_exist_lock);
 568
 569         return ret;
 570 }
 571 EXPORT_SYMBOL_GPL(iio_read_channel_raw);
 572
 573 int iio_read_channel_average_raw(struct iio_channel *chan, int *val)
 574 {
 575         int ret;
 576
 577         mutex_lock(&chan->indio_dev->info_exist_lock);
 578         if (chan->indio_dev->info == NULL) {
 579                 ret = -ENODEV;
 580                 goto err_unlock;
 581         }
 582
 583         ret = iio_channel_read(chan, val, NULL, IIO_CHAN_INFO_AVERAGE_RAW);
 584 err_unlock:
 585         mutex_unlock(&chan->indio_dev->info_exist_lock);
 586
 587         return ret;
 588 }
 589 EXPORT_SYMBOL_GPL(iio_read_channel_average_raw);
 590
 591 static int iio_convert_raw_to_processed_unlocked(struct iio_channel *chan,
 592         int raw, int *processed, unsigned int scale)
 593 {
 594         int scale_type, scale_val, scale_val2, offset;
 595         s64 raw64 = raw;
 596         int ret;
 597
 598         ret = iio_channel_read(chan, &offset, NULL, IIO_CHAN_INFO_OFFSET);
 599         if (ret >= 0)
 600                 raw64 += offset;
 601
 602         scale_type = iio_channel_read(chan, &scale_val, &scale_val2,
 603                                         IIO_CHAN_INFO_SCALE);
 604         if (scale_type < 0) {
 605                 /*
 606                  * Just pass raw values as processed if no scaling is
 607                  * available.
 608                  */
 609                 *processed = raw;
 610                 return 0;
 611         }
 612
 613         switch (scale_type) {
 614         case IIO_VAL_INT:
 615                 *processed = raw64 * scale_val;
 616                 break;
 617         case IIO_VAL_INT_PLUS_MICRO:
 618                 if (scale_val2 < 0)
 619                         *processed = -raw64 * scale_val;
 620                 else
 621                         *processed = raw64 * scale_val;
 622                 *processed += div_s64(raw64 * (s64)scale_val2 * scale,
 623                                       1000000LL);
 624                 break;
 625         case IIO_VAL_INT_PLUS_NANO:
 626                 if (scale_val2 < 0)
 627                         *processed = -raw64 * scale_val;
 628                 else
 629                         *processed = raw64 * scale_val;
 630                 *processed += div_s64(raw64 * (s64)scale_val2 * scale,
 631                                       1000000000LL);
 632                 break;
 633         case IIO_VAL_FRACTIONAL:
 634                 *processed = div_s64(raw64 * (s64)scale_val * scale,
 635                                      scale_val2);
 636                 break;
 637         case IIO_VAL_FRACTIONAL_LOG2:
 638                 *processed = (raw64 * (s64)scale_val * scale) >> scale_val2;
 639                 break;
 640         default:
 641                 return -EINVAL;
 642         }
 643
 644         return 0;
 645 }
 646
 647 int iio_convert_raw_to_processed(struct iio_channel *chan, int raw,
 648         int *processed, unsigned int scale)
 649 {
 650         int ret;
 651
 652         mutex_lock(&chan->indio_dev->info_exist_lock);
 653         if (chan->indio_dev->info == NULL) {
 654                 ret = -ENODEV;
 655                 goto err_unlock;
 656         }
 657
 658         ret = iio_convert_raw_to_processed_unlocked(chan, raw, processed,
 659                                                         scale);
 660 err_unlock:
 661         mutex_unlock(&chan->indio_dev->info_exist_lock);
 662
 663         return ret;
 664 }
 665 EXPORT_SYMBOL_GPL(iio_convert_raw_to_processed);
 666
 667 int iio_read_channel_attribute(struct iio_channel *chan, int *val, int *val2,
 668                                enum iio_chan_info_enum attribute)
 669 {
 670         int ret;
 671
 672         mutex_lock(&chan->indio_dev->info_exist_lock);
 673         if (chan->indio_dev->info == NULL) {
 674                 ret = -ENODEV;
 675                 goto err_unlock;
 676         }
 677
 678         ret = iio_channel_read(chan, val, val2, attribute);
 679 err_unlock:
 680         mutex_unlock(&chan->indio_dev->info_exist_lock);
 681
 682         return ret;
 683 }
 684 EXPORT_SYMBOL_GPL(iio_read_channel_attribute);
 685
 686 int iio_read_channel_offset(struct iio_channel *chan, int *val, int *val2)
 687 {
 688         return iio_read_channel_attribute(chan, val, val2, IIO_CHAN_INFO_OFFSET);
 689 }
 690 EXPORT_SYMBOL_GPL(iio_read_channel_offset);
 691
 692 int iio_read_channel_processed(struct iio_channel *chan, int *val)
 693 {
 694         int ret;
 695
 696         mutex_lock(&chan->indio_dev->info_exist_lock);
 697         if (chan->indio_dev->info == NULL) {
 698                 ret = -ENODEV;
 699                 goto err_unlock;
 700         }
 701
 702         if (iio_channel_has_info(chan->channel, IIO_CHAN_INFO_PROCESSED)) {
 703                 ret = iio_channel_read(chan, val, NULL,
 704                                        IIO_CHAN_INFO_PROCESSED);
 705         } else {
 706                 ret = iio_channel_read(chan, val, NULL, IIO_CHAN_INFO_RAW);
 707                 if (ret < 0)
 708                         goto err_unlock;
 709                 ret = iio_convert_raw_to_processed_unlocked(chan, *val, val, 1);
 710         }
 711
 712 err_unlock:
 713         mutex_unlock(&chan->indio_dev->info_exist_lock);
 714
 715         return ret;
 716 }
 717 EXPORT_SYMBOL_GPL(iio_read_channel_processed);
 718
 719 int iio_read_channel_scale(struct iio_channel *chan, int *val, int *val2)
 720 {
 721         return iio_read_channel_attribute(chan, val, val2, IIO_CHAN_INFO_SCALE);
 722 }
 723 EXPORT_SYMBOL_GPL(iio_read_channel_scale);
 724
 725 static int iio_channel_read_avail(struct iio_channel *chan,
 726                                   const int **vals, int *type, int *length,
 727                                   enum iio_chan_info_enum info)
 728 {
 729         if (!iio_channel_has_available(chan->channel, info))
 730                 return -EINVAL;
 731
 732         return chan->indio_dev->info->read_avail(chan->indio_dev, chan->channel,
 733                                                  vals, type, length, info);
 734 }
 735
 736 int iio_read_avail_channel_raw(struct iio_channel *chan,
 737                                const int **vals, int *length)
 738 {
 739         int ret;
 740         int type;
 741
 742         mutex_lock(&chan->indio_dev->info_exist_lock);
 743         if (!chan->indio_dev->info) {
 744                 ret = -ENODEV;
 745                 goto err_unlock;
 746         }
 747
 748         ret = iio_channel_read_avail(chan,
 749                                      vals, &type, length, IIO_CHAN_INFO_RAW);
 750 err_unlock:
 751         mutex_unlock(&chan->indio_dev->info_exist_lock);
 752
 753         if (ret >= 0 && type != IIO_VAL_INT)
 754                 /* raw values are assumed to be IIO_VAL_INT */
 755                 ret = -EINVAL;
 756
 757         return ret;
 758 }
 759 EXPORT_SYMBOL_GPL(iio_read_avail_channel_raw);
 760
 761 static int iio_channel_read_max(struct iio_channel *chan,
 762                                 int *val, int *val2, int *type,
 763                                 enum iio_chan_info_enum info)
 764 {
 765         int unused;
 766         const int *vals;
 767         int length;
 768         int ret;
 769
 770         if (!val2)
 771                 val2 = &unused;
 772
 773         ret = iio_channel_read_avail(chan, &vals, type, &length, info);
 774         switch (ret) {
 775         case IIO_AVAIL_RANGE:
 776                 switch (*type) {
 777                 case IIO_VAL_INT:
 778                         *val = vals[2];
 779                         break;
 780                 default:
 781                         *val = vals[4];
 782                         *val2 = vals[5];
 783                 }
 784                 return 0;
 785
 786         case IIO_AVAIL_LIST:
 787                 if (length <= 0)
 788                         return -EINVAL;
 789                 switch (*type) {
 790                 case IIO_VAL_INT:
 791                         *val = vals[--length];
 792                         while (length) {
 793                                 if (vals[--length] > *val)
 794                                         *val = vals[length];
 795                         }
 796                         break;
 797                 default:
 798                         /* FIXME: learn about max for other iio values */
 799                         return -EINVAL;
 800                 }
 801                 return 0;
 802
 803         default:
 804                 return ret;
 805         }
 806 }
 807
 808 int iio_read_max_channel_raw(struct iio_channel *chan, int *val)
 809 {
 810         int ret;
 811         int type;
 812
 813         mutex_lock(&chan->indio_dev->info_exist_lock);
 814         if (!chan->indio_dev->info) {
 815                 ret = -ENODEV;
 816                 goto err_unlock;
 817         }
 818
 819         ret = iio_channel_read_max(chan, val, NULL, &type, IIO_CHAN_INFO_RAW);
 820 err_unlock:
 821         mutex_unlock(&chan->indio_dev->info_exist_lock);
 822
 823         return ret;
 824 }
 825 EXPORT_SYMBOL_GPL(iio_read_max_channel_raw);
 826
 827 int iio_get_channel_type(struct iio_channel *chan, enum iio_chan_type *type)
 828 {
 829         int ret = 0;
 830         /* Need to verify underlying driver has not gone away */
 831
 832         mutex_lock(&chan->indio_dev->info_exist_lock);
 833         if (chan->indio_dev->info == NULL) {
 834                 ret = -ENODEV;
 835                 goto err_unlock;
 836         }
 837
 838         *type = chan->channel->type;
 839 err_unlock:
 840         mutex_unlock(&chan->indio_dev->info_exist_lock);
 841
 842         return ret;
 843 }
 844 EXPORT_SYMBOL_GPL(iio_get_channel_type);
 845
 846 static int iio_channel_write(struct iio_channel *chan, int val, int val2,
 847                              enum iio_chan_info_enum info)
 848 {
 849         return chan->indio_dev->info->write_raw(chan->indio_dev,
 850                                                 chan->channel, val, val2, info);
 851 }
 852
 853 int iio_write_channel_attribute(struct iio_channel *chan, int val, int val2,
 854                                 enum iio_chan_info_enum attribute)
 855 {
 856         int ret;
 857
 858         mutex_lock(&chan->indio_dev->info_exist_lock);
 859         if (chan->indio_dev->info == NULL) {
 860                 ret = -ENODEV;
 861                 goto err_unlock;
 862         }
 863
 864         ret = iio_channel_write(chan, val, val2, attribute);
 865 err_unlock:
 866         mutex_unlock(&chan->indio_dev->info_exist_lock);
 867
 868         return ret;
 869 }
 870 EXPORT_SYMBOL_GPL(iio_write_channel_attribute);
 871
 872 int iio_write_channel_raw(struct iio_channel *chan, int val)
 873 {
 874         return iio_write_channel_attribute(chan, val, 0, IIO_CHAN_INFO_RAW);
 875 }
 876 EXPORT_SYMBOL_GPL(iio_write_channel_raw);
 877
 878 unsigned int iio_get_channel_ext_info_count(struct iio_channel *chan)
 879 {
 880         const struct iio_chan_spec_ext_info *ext_info;
 881         unsigned int i = 0;
 882
 883         if (!chan->channel->ext_info)
 884                 return i;
 885
 886         for (ext_info = chan->channel->ext_info; ext_info->name; ext_info++)
 887                 ++i;
 888
 889         return i;
 890 }
 891 EXPORT_SYMBOL_GPL(iio_get_channel_ext_info_count);
 892
 893 static const struct iio_chan_spec_ext_info *iio_lookup_ext_info(
 894                                                 const struct iio_channel *chan,
 895                                                 const char *attr)
 896 {
 897         const struct iio_chan_spec_ext_info *ext_info;
 898
 899         if (!chan->channel->ext_info)
 900                 return NULL;
 901
 902         for (ext_info = chan->channel->ext_info; ext_info->name; ++ext_info) {
 903                 if (!strcmp(attr, ext_info->name))
 904                         return ext_info;
 905         }
 906
 907         return NULL;
 908 }
 909
 910 ssize_t iio_read_channel_ext_info(struct iio_channel *chan,
 911                                   const char *attr, char *buf)
 912 {
 913         const struct iio_chan_spec_ext_info *ext_info;
 914
 915         ext_info = iio_lookup_ext_info(chan, attr);
 916         if (!ext_info)
 917                 return -EINVAL;
 918
 919         return ext_info->read(chan->indio_dev, ext_info->private,
 920                               chan->channel, buf);
 921 }
 922 EXPORT_SYMBOL_GPL(iio_read_channel_ext_info);
 923
 924 ssize_t iio_write_channel_ext_info(struct iio_channel *chan, const char *attr,
 925                                    const char *buf, size_t len)
 926 {
 927         const struct iio_chan_spec_ext_info *ext_info;
 928
 929         ext_info = iio_lookup_ext_info(chan, attr);
 930         if (!ext_info)
 931                 return -EINVAL;
 932
 933         return ext_info->write(chan->indio_dev, ext_info->private,
 934                                chan->channel, buf, len);
 935 }
 936 EXPORT_SYMBOL_GPL(iio_write_channel_ext_info);