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(&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 %s:%s(%i)\n",
 209                                 np->full_name, 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 struct iio_channel *iio_channel_get_all(struct device *dev)
 360 {
 361         const char *name;
 362         struct iio_channel *chans;
 363         struct iio_map_internal *c = NULL;
 364         int nummaps = 0;
 365         int mapind = 0;
 366         int i, ret;
 367
 368         if (dev == NULL)
 369                 return ERR_PTR(-EINVAL);
 370
 371         chans = of_iio_channel_get_all(dev);
 372         if (chans)
 373                 return chans;
 374
 375         name = dev_name(dev);
 376
 377         mutex_lock(&iio_map_list_lock);
 378         /* first count the matching maps */
 379         list_for_each_entry(c, &iio_map_list, l)
 380                 if (name && strcmp(name, c->map->consumer_dev_name) != 0)
 381                         continue;
 382                 else
 383                         nummaps++;
 384
 385         if (nummaps == 0) {
 386                 ret = -ENODEV;
 387                 goto error_ret;
 388         }
 389
 390         /* NULL terminated array to save passing size */
 391         chans = kzalloc(sizeof(*chans)*(nummaps + 1), GFP_KERNEL);
 392         if (chans == NULL) {
 393                 ret = -ENOMEM;
 394                 goto error_ret;
 395         }
 396
 397         /* for each map fill in the chans element */
 398         list_for_each_entry(c, &iio_map_list, l) {
 399                 if (name && strcmp(name, c->map->consumer_dev_name) != 0)
 400                         continue;
 401                 chans[mapind].indio_dev = c->indio_dev;
 402                 chans[mapind].data = c->map->consumer_data;
 403                 chans[mapind].channel =
 404                         iio_chan_spec_from_name(chans[mapind].indio_dev,
 405                                                 c->map->adc_channel_label);
 406                 if (chans[mapind].channel == NULL) {
 407                         ret = -EINVAL;
 408                         goto error_free_chans;
 409                 }
 410                 iio_device_get(chans[mapind].indio_dev);
 411                 mapind++;
 412         }
 413         if (mapind == 0) {
 414                 ret = -ENODEV;
 415                 goto error_free_chans;
 416         }
 417         mutex_unlock(&iio_map_list_lock);
 418
 419         return chans;
 420
 421 error_free_chans:
 422         for (i = 0; i < nummaps; i++)
 423                 iio_device_put(chans[i].indio_dev);
 424         kfree(chans);
 425 error_ret:
 426         mutex_unlock(&iio_map_list_lock);
 427
 428         return ERR_PTR(ret);
 429 }
 430 EXPORT_SYMBOL_GPL(iio_channel_get_all);
 431
 432 void iio_channel_release_all(struct iio_channel *channels)
 433 {
 434         struct iio_channel *chan = &channels[0];
 435
 436         while (chan->indio_dev) {
 437                 iio_device_put(chan->indio_dev);
 438                 chan++;
 439         }
 440         kfree(channels);
 441 }
 442 EXPORT_SYMBOL_GPL(iio_channel_release_all);
 443
 444 static int iio_channel_read(struct iio_channel *chan, int *val, int *val2,
 445         enum iio_chan_info_enum info)
 446 {
 447         int unused;
 448         int vals[INDIO_MAX_RAW_ELEMENTS];
 449         int ret;
 450         int val_len = 2;
 451
 452         if (val2 == NULL)
 453                 val2 = &unused;
 454
 455         if(!iio_channel_has_info(chan->channel, info))
 456                 return -EINVAL;
 457
 458         if (chan->indio_dev->info->read_raw_multi) {
 459                 ret = chan->indio_dev->info->read_raw_multi(chan->indio_dev,
 460                                         chan->channel, INDIO_MAX_RAW_ELEMENTS,
 461                                         vals, &val_len, info);
 462                 *val = vals[0];
 463                 *val2 = vals[1];
 464         } else
 465                 ret = chan->indio_dev->info->read_raw(chan->indio_dev,
 466                                         chan->channel, val, val2, info);
 467
 468         return ret;
 469 }
 470
 471 int iio_read_channel_raw(struct iio_channel *chan, int *val)
 472 {
 473         int ret;
 474
 475         mutex_lock(&chan->indio_dev->info_exist_lock);
 476         if (chan->indio_dev->info == NULL) {
 477                 ret = -ENODEV;
 478                 goto err_unlock;
 479         }
 480
 481         ret = iio_channel_read(chan, val, NULL, IIO_CHAN_INFO_RAW);
 482 err_unlock:
 483         mutex_unlock(&chan->indio_dev->info_exist_lock);
 484
 485         return ret;
 486 }
 487 EXPORT_SYMBOL_GPL(iio_read_channel_raw);
 488
 489 int iio_read_channel_average_raw(struct iio_channel *chan, int *val)
 490 {
 491         int ret;
 492
 493         mutex_lock(&chan->indio_dev->info_exist_lock);
 494         if (chan->indio_dev->info == NULL) {
 495                 ret = -ENODEV;
 496                 goto err_unlock;
 497         }
 498
 499         ret = iio_channel_read(chan, val, NULL, IIO_CHAN_INFO_AVERAGE_RAW);
 500 err_unlock:
 501         mutex_unlock(&chan->indio_dev->info_exist_lock);
 502
 503         return ret;
 504 }
 505 EXPORT_SYMBOL_GPL(iio_read_channel_average_raw);
 506
 507 static int iio_convert_raw_to_processed_unlocked(struct iio_channel *chan,
 508         int raw, int *processed, unsigned int scale)
 509 {
 510         int scale_type, scale_val, scale_val2, offset;
 511         s64 raw64 = raw;
 512         int ret;
 513
 514         ret = iio_channel_read(chan, &offset, NULL, IIO_CHAN_INFO_OFFSET);
 515         if (ret >= 0)
 516                 raw64 += offset;
 517
 518         scale_type = iio_channel_read(chan, &scale_val, &scale_val2,
 519                                         IIO_CHAN_INFO_SCALE);
 520         if (scale_type < 0)
 521                 return scale_type;
 522
 523         switch (scale_type) {
 524         case IIO_VAL_INT:
 525                 *processed = raw64 * scale_val;
 526                 break;
 527         case IIO_VAL_INT_PLUS_MICRO:
 528                 if (scale_val2 < 0)
 529                         *processed = -raw64 * scale_val;
 530                 else
 531                         *processed = raw64 * scale_val;
 532                 *processed += div_s64(raw64 * (s64)scale_val2 * scale,
 533                                       1000000LL);
 534                 break;
 535         case IIO_VAL_INT_PLUS_NANO:
 536                 if (scale_val2 < 0)
 537                         *processed = -raw64 * scale_val;
 538                 else
 539                         *processed = raw64 * scale_val;
 540                 *processed += div_s64(raw64 * (s64)scale_val2 * scale,
 541                                       1000000000LL);
 542                 break;
 543         case IIO_VAL_FRACTIONAL:
 544                 *processed = div_s64(raw64 * (s64)scale_val * scale,
 545                                      scale_val2);
 546                 break;
 547         case IIO_VAL_FRACTIONAL_LOG2:
 548                 *processed = (raw64 * (s64)scale_val * scale) >> scale_val2;
 549                 break;
 550         default:
 551                 return -EINVAL;
 552         }
 553
 554         return 0;
 555 }
 556
 557 int iio_convert_raw_to_processed(struct iio_channel *chan, int raw,
 558         int *processed, unsigned int scale)
 559 {
 560         int ret;
 561
 562         mutex_lock(&chan->indio_dev->info_exist_lock);
 563         if (chan->indio_dev->info == NULL) {
 564                 ret = -ENODEV;
 565                 goto err_unlock;
 566         }
 567
 568         ret = iio_convert_raw_to_processed_unlocked(chan, raw, processed,
 569                                                         scale);
 570 err_unlock:
 571         mutex_unlock(&chan->indio_dev->info_exist_lock);
 572
 573         return ret;
 574 }
 575 EXPORT_SYMBOL_GPL(iio_convert_raw_to_processed);
 576
 577 int iio_read_channel_processed(struct iio_channel *chan, int *val)
 578 {
 579         int ret;
 580
 581         mutex_lock(&chan->indio_dev->info_exist_lock);
 582         if (chan->indio_dev->info == NULL) {
 583                 ret = -ENODEV;
 584                 goto err_unlock;
 585         }
 586
 587         if (iio_channel_has_info(chan->channel, IIO_CHAN_INFO_PROCESSED)) {
 588                 ret = iio_channel_read(chan, val, NULL,
 589                                        IIO_CHAN_INFO_PROCESSED);
 590         } else {
 591                 ret = iio_channel_read(chan, val, NULL, IIO_CHAN_INFO_RAW);
 592                 if (ret < 0)
 593                         goto err_unlock;
 594                 ret = iio_convert_raw_to_processed_unlocked(chan, *val, val, 1);
 595         }
 596
 597 err_unlock:
 598         mutex_unlock(&chan->indio_dev->info_exist_lock);
 599
 600         return ret;
 601 }
 602 EXPORT_SYMBOL_GPL(iio_read_channel_processed);
 603
 604 int iio_read_channel_scale(struct iio_channel *chan, int *val, int *val2)
 605 {
 606         int ret;
 607
 608         mutex_lock(&chan->indio_dev->info_exist_lock);
 609         if (chan->indio_dev->info == NULL) {
 610                 ret = -ENODEV;
 611                 goto err_unlock;
 612         }
 613
 614         ret = iio_channel_read(chan, val, val2, IIO_CHAN_INFO_SCALE);
 615 err_unlock:
 616         mutex_unlock(&chan->indio_dev->info_exist_lock);
 617
 618         return ret;
 619 }
 620 EXPORT_SYMBOL_GPL(iio_read_channel_scale);
 621
 622 int iio_get_channel_type(struct iio_channel *chan, enum iio_chan_type *type)
 623 {
 624         int ret = 0;
 625         /* Need to verify underlying driver has not gone away */
 626
 627         mutex_lock(&chan->indio_dev->info_exist_lock);
 628         if (chan->indio_dev->info == NULL) {
 629                 ret = -ENODEV;
 630                 goto err_unlock;
 631         }
 632
 633         *type = chan->channel->type;
 634 err_unlock:
 635         mutex_unlock(&chan->indio_dev->info_exist_lock);
 636
 637         return ret;
 638 }
 639 EXPORT_SYMBOL_GPL(iio_get_channel_type);
 640
 641 static int iio_channel_write(struct iio_channel *chan, int val, int val2,
 642                              enum iio_chan_info_enum info)
 643 {
 644         return chan->indio_dev->info->write_raw(chan->indio_dev,
 645                                                 chan->channel, val, val2, info);
 646 }
 647
 648 int iio_write_channel_raw(struct iio_channel *chan, int val)
 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_channel_write(chan, val, 0, IIO_CHAN_INFO_RAW);
 659 err_unlock:
 660         mutex_unlock(&chan->indio_dev->info_exist_lock);
 661
 662         return ret;
 663 }
 664 EXPORT_SYMBOL_GPL(iio_write_channel_raw);