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;
  65         struct list_head *pos, *tmp;
  66
  67         mutex_lock(&iio_map_list_lock);
  68         list_for_each_safe(pos, tmp, &iio_map_list) {
  69                 mapi = list_entry(pos, struct iio_map_internal, l);
  70                 if (indio_dev == mapi->indio_dev) {
  71                         list_del(&mapi->l);
  72                         kfree(mapi);
  73                         ret = 0;
  74                 }
  75         }
  76         mutex_unlock(&iio_map_list_lock);
  77         return ret;
  78 }
  79 EXPORT_SYMBOL_GPL(iio_map_array_unregister);
  80
  81 static const struct iio_chan_spec
  82 *iio_chan_spec_from_name(const struct iio_dev *indio_dev, const char *name)
  83 {
  84         int i;
  85         const struct iio_chan_spec *chan = NULL;
  86
  87         for (i = 0; i < indio_dev->num_channels; i++)
  88                 if (indio_dev->channels[i].datasheet_name &&
  89                     strcmp(name, indio_dev->channels[i].datasheet_name) == 0) {
  90                         chan = &indio_dev->channels[i];
  91                         break;
  92                 }
  93         return chan;
  94 }
  95
  96 #ifdef CONFIG_OF
  97
  98 static int iio_dev_node_match(struct device *dev, void *data)
  99 {
 100         return dev->of_node == data && dev->type == &iio_device_type;
 101 }
 102
 103 static int __of_iio_channel_get(struct iio_channel *channel,
 104                                 struct device_node *np, int index)
 105 {
 106         struct device *idev;
 107         struct iio_dev *indio_dev;
 108         int err;
 109         struct of_phandle_args iiospec;
 110
 111         err = of_parse_phandle_with_args(np, "io-channels",
 112                                          "#io-channel-cells",
 113                                          index, &iiospec);
 114         if (err)
 115                 return err;
 116
 117         idev = bus_find_device(&iio_bus_type, NULL, iiospec.np,
 118                                iio_dev_node_match);
 119         of_node_put(iiospec.np);
 120         if (idev == NULL)
 121                 return -EPROBE_DEFER;
 122
 123         indio_dev = dev_to_iio_dev(idev);
 124         channel->indio_dev = indio_dev;
 125         index = iiospec.args_count ? iiospec.args[0] : 0;
 126         if (index >= indio_dev->num_channels) {
 127                 err = -EINVAL;
 128                 goto err_put;
 129         }
 130         channel->channel = &indio_dev->channels[index];
 131
 132         return 0;
 133
 134 err_put:
 135         iio_device_put(indio_dev);
 136         return err;
 137 }
 138
 139 static struct iio_channel *of_iio_channel_get(struct device_node *np, int index)
 140 {
 141         struct iio_channel *channel;
 142         int err;
 143
 144         if (index < 0)
 145                 return ERR_PTR(-EINVAL);
 146
 147         channel = kzalloc(sizeof(*channel), GFP_KERNEL);
 148         if (channel == NULL)
 149                 return ERR_PTR(-ENOMEM);
 150
 151         err = __of_iio_channel_get(channel, np, index);
 152         if (err)
 153                 goto err_free_channel;
 154
 155         return channel;
 156
 157 err_free_channel:
 158         kfree(channel);
 159         return ERR_PTR(err);
 160 }
 161
 162 static struct iio_channel *of_iio_channel_get_by_name(struct device_node *np,
 163                                                       const char *name)
 164 {
 165         struct iio_channel *chan = NULL;
 166
 167         /* Walk up the tree of devices looking for a matching iio channel */
 168         while (np) {
 169                 int index = 0;
 170
 171                 /*
 172                  * For named iio channels, first look up the name in the
 173                  * "io-channel-names" property.  If it cannot be found, the
 174                  * index will be an error code, and of_iio_channel_get()
 175                  * will fail.
 176                  */
 177                 if (name)
 178                         index = of_property_match_string(np, "io-channel-names",
 179                                                          name);
 180                 chan = of_iio_channel_get(np, index);
 181                 if (!IS_ERR(chan))
 182                         break;
 183                 else if (name && index >= 0) {
 184                         pr_err("ERROR: could not get IIO channel %s:%s(%i)\n",
 185                                 np->full_name, name ? name : "", index);
 186                         return chan;
 187                 }
 188
 189                 /*
 190                  * No matching IIO channel found on this node.
 191                  * If the parent node has a "io-channel-ranges" property,
 192                  * then we can try one of its channels.
 193                  */
 194                 np = np->parent;
 195                 if (np && !of_get_property(np, "io-channel-ranges", NULL))
 196                         break;
 197         }
 198         return chan;
 199 }
 200
 201 static struct iio_channel *of_iio_channel_get_all(struct device *dev)
 202 {
 203         struct iio_channel *chans;
 204         int i, mapind, nummaps = 0;
 205         int ret;
 206
 207         do {
 208                 ret = of_parse_phandle_with_args(dev->of_node,
 209                                                  "io-channels",
 210                                                  "#io-channel-cells",
 211                                                  nummaps, NULL);
 212                 if (ret < 0)
 213                         break;
 214         } while (++nummaps);
 215
 216         if (nummaps == 0)       /* no error, return NULL to search map table */
 217                 return NULL;
 218
 219         /* NULL terminated array to save passing size */
 220         chans = kcalloc(nummaps + 1, sizeof(*chans), GFP_KERNEL);
 221         if (chans == NULL)
 222                 return ERR_PTR(-ENOMEM);
 223
 224         /* Search for OF matches */
 225         for (mapind = 0; mapind < nummaps; mapind++) {
 226                 ret = __of_iio_channel_get(&chans[mapind], dev->of_node,
 227                                            mapind);
 228                 if (ret)
 229                         goto error_free_chans;
 230         }
 231         return chans;
 232
 233 error_free_chans:
 234         for (i = 0; i < mapind; i++)
 235                 iio_device_put(chans[i].indio_dev);
 236         kfree(chans);
 237         return ERR_PTR(ret);
 238 }
 239
 240 #else /* CONFIG_OF */
 241
 242 static inline struct iio_channel *
 243 of_iio_channel_get_by_name(struct device_node *np, const char *name)
 244 {
 245         return NULL;
 246 }
 247
 248 static inline struct iio_channel *of_iio_channel_get_all(struct device *dev)
 249 {
 250         return NULL;
 251 }
 252
 253 #endif /* CONFIG_OF */
 254
 255 static struct iio_channel *iio_channel_get_sys(const char *name,
 256                                                const char *channel_name)
 257 {
 258         struct iio_map_internal *c_i = NULL, *c = NULL;
 259         struct iio_channel *channel;
 260         int err;
 261
 262         if (name == NULL && channel_name == NULL)
 263                 return ERR_PTR(-ENODEV);
 264
 265         /* first find matching entry the channel map */
 266         mutex_lock(&iio_map_list_lock);
 267         list_for_each_entry(c_i, &iio_map_list, l) {
 268                 if ((name && strcmp(name, c_i->map->consumer_dev_name) != 0) ||
 269                     (channel_name &&
 270                      strcmp(channel_name, c_i->map->consumer_channel) != 0))
 271                         continue;
 272                 c = c_i;
 273                 iio_device_get(c->indio_dev);
 274                 break;
 275         }
 276         mutex_unlock(&iio_map_list_lock);
 277         if (c == NULL)
 278                 return ERR_PTR(-ENODEV);
 279
 280         channel = kzalloc(sizeof(*channel), GFP_KERNEL);
 281         if (channel == NULL) {
 282                 err = -ENOMEM;
 283                 goto error_no_mem;
 284         }
 285
 286         channel->indio_dev = c->indio_dev;
 287
 288         if (c->map->adc_channel_label) {
 289                 channel->channel =
 290                         iio_chan_spec_from_name(channel->indio_dev,
 291                                                 c->map->adc_channel_label);
 292
 293                 if (channel->channel == NULL) {
 294                         err = -EINVAL;
 295                         goto error_no_chan;
 296                 }
 297         }
 298
 299         return channel;
 300
 301 error_no_chan:
 302         kfree(channel);
 303 error_no_mem:
 304         iio_device_put(c->indio_dev);
 305         return ERR_PTR(err);
 306 }
 307
 308 struct iio_channel *iio_channel_get(struct device *dev,
 309                                     const char *channel_name)
 310 {
 311         const char *name = dev ? dev_name(dev) : NULL;
 312         struct iio_channel *channel;
 313
 314         if (dev) {
 315                 channel = of_iio_channel_get_by_name(dev->of_node,
 316                                                      channel_name);
 317                 if (channel != NULL)
 318                         return channel;
 319         }
 320         return iio_channel_get_sys(name, channel_name);
 321 }
 322 EXPORT_SYMBOL_GPL(iio_channel_get);
 323
 324 void iio_channel_release(struct iio_channel *channel)
 325 {
 326         iio_device_put(channel->indio_dev);
 327         kfree(channel);
 328 }
 329 EXPORT_SYMBOL_GPL(iio_channel_release);
 330
 331 struct iio_channel *iio_channel_get_all(struct device *dev)
 332 {
 333         const char *name;
 334         struct iio_channel *chans;
 335         struct iio_map_internal *c = NULL;
 336         int nummaps = 0;
 337         int mapind = 0;
 338         int i, ret;
 339
 340         if (dev == NULL)
 341                 return ERR_PTR(-EINVAL);
 342
 343         chans = of_iio_channel_get_all(dev);
 344         if (chans)
 345                 return chans;
 346
 347         name = dev_name(dev);
 348
 349         mutex_lock(&iio_map_list_lock);
 350         /* first count the matching maps */
 351         list_for_each_entry(c, &iio_map_list, l)
 352                 if (name && strcmp(name, c->map->consumer_dev_name) != 0)
 353                         continue;
 354                 else
 355                         nummaps++;
 356
 357         if (nummaps == 0) {
 358                 ret = -ENODEV;
 359                 goto error_ret;
 360         }
 361
 362         /* NULL terminated array to save passing size */
 363         chans = kzalloc(sizeof(*chans)*(nummaps + 1), GFP_KERNEL);
 364         if (chans == NULL) {
 365                 ret = -ENOMEM;
 366                 goto error_ret;
 367         }
 368
 369         /* for each map fill in the chans element */
 370         list_for_each_entry(c, &iio_map_list, l) {
 371                 if (name && strcmp(name, c->map->consumer_dev_name) != 0)
 372                         continue;
 373                 chans[mapind].indio_dev = c->indio_dev;
 374                 chans[mapind].data = c->map->consumer_data;
 375                 chans[mapind].channel =
 376                         iio_chan_spec_from_name(chans[mapind].indio_dev,
 377                                                 c->map->adc_channel_label);
 378                 if (chans[mapind].channel == NULL) {
 379                         ret = -EINVAL;
 380                         goto error_free_chans;
 381                 }
 382                 iio_device_get(chans[mapind].indio_dev);
 383                 mapind++;
 384         }
 385         if (mapind == 0) {
 386                 ret = -ENODEV;
 387                 goto error_free_chans;
 388         }
 389         mutex_unlock(&iio_map_list_lock);
 390
 391         return chans;
 392
 393 error_free_chans:
 394         for (i = 0; i < nummaps; i++)
 395                 iio_device_put(chans[i].indio_dev);
 396         kfree(chans);
 397 error_ret:
 398         mutex_unlock(&iio_map_list_lock);
 399
 400         return ERR_PTR(ret);
 401 }
 402 EXPORT_SYMBOL_GPL(iio_channel_get_all);
 403
 404 void iio_channel_release_all(struct iio_channel *channels)
 405 {
 406         struct iio_channel *chan = &channels[0];
 407
 408         while (chan->indio_dev) {
 409                 iio_device_put(chan->indio_dev);
 410                 chan++;
 411         }
 412         kfree(channels);
 413 }
 414 EXPORT_SYMBOL_GPL(iio_channel_release_all);
 415
 416 static int iio_channel_read(struct iio_channel *chan, int *val, int *val2,
 417         enum iio_chan_info_enum info)
 418 {
 419         int unused;
 420
 421         if (val2 == NULL)
 422                 val2 = &unused;
 423
 424         return chan->indio_dev->info->read_raw(chan->indio_dev, chan->channel,
 425                                                 val, val2, info);
 426 }
 427
 428 int iio_read_channel_raw(struct iio_channel *chan, int *val)
 429 {
 430         int ret;
 431
 432         mutex_lock(&chan->indio_dev->info_exist_lock);
 433         if (chan->indio_dev->info == NULL) {
 434                 ret = -ENODEV;
 435                 goto err_unlock;
 436         }
 437
 438         ret = iio_channel_read(chan, val, NULL, IIO_CHAN_INFO_RAW);
 439 err_unlock:
 440         mutex_unlock(&chan->indio_dev->info_exist_lock);
 441
 442         return ret;
 443 }
 444 EXPORT_SYMBOL_GPL(iio_read_channel_raw);
 445
 446 static int iio_convert_raw_to_processed_unlocked(struct iio_channel *chan,
 447         int raw, int *processed, unsigned int scale)
 448 {
 449         int scale_type, scale_val, scale_val2, offset;
 450         s64 raw64 = raw;
 451         int ret;
 452
 453         ret = iio_channel_read(chan, &offset, NULL, IIO_CHAN_INFO_OFFSET);
 454         if (ret >= 0)
 455                 raw64 += offset;
 456
 457         scale_type = iio_channel_read(chan, &scale_val, &scale_val2,
 458                                         IIO_CHAN_INFO_SCALE);
 459         if (scale_type < 0)
 460                 return scale_type;
 461
 462         switch (scale_type) {
 463         case IIO_VAL_INT:
 464                 *processed = raw64 * scale_val;
 465                 break;
 466         case IIO_VAL_INT_PLUS_MICRO:
 467                 if (scale_val2 < 0)
 468                         *processed = -raw64 * scale_val;
 469                 else
 470                         *processed = raw64 * scale_val;
 471                 *processed += div_s64(raw64 * (s64)scale_val2 * scale,
 472                                       1000000LL);
 473                 break;
 474         case IIO_VAL_INT_PLUS_NANO:
 475                 if (scale_val2 < 0)
 476                         *processed = -raw64 * scale_val;
 477                 else
 478                         *processed = raw64 * scale_val;
 479                 *processed += div_s64(raw64 * (s64)scale_val2 * scale,
 480                                       1000000000LL);
 481                 break;
 482         case IIO_VAL_FRACTIONAL:
 483                 *processed = div_s64(raw64 * (s64)scale_val * scale,
 484                                      scale_val2);
 485                 break;
 486         case IIO_VAL_FRACTIONAL_LOG2:
 487                 *processed = (raw64 * (s64)scale_val * scale) >> scale_val2;
 488                 break;
 489         default:
 490                 return -EINVAL;
 491         }
 492
 493         return 0;
 494 }
 495
 496 int iio_convert_raw_to_processed(struct iio_channel *chan, int raw,
 497         int *processed, unsigned int scale)
 498 {
 499         int ret;
 500
 501         mutex_lock(&chan->indio_dev->info_exist_lock);
 502         if (chan->indio_dev->info == NULL) {
 503                 ret = -ENODEV;
 504                 goto err_unlock;
 505         }
 506
 507         ret = iio_convert_raw_to_processed_unlocked(chan, raw, processed,
 508                                                         scale);
 509 err_unlock:
 510         mutex_unlock(&chan->indio_dev->info_exist_lock);
 511
 512         return ret;
 513 }
 514 EXPORT_SYMBOL_GPL(iio_convert_raw_to_processed);
 515
 516 int iio_read_channel_processed(struct iio_channel *chan, int *val)
 517 {
 518         int ret;
 519
 520         mutex_lock(&chan->indio_dev->info_exist_lock);
 521         if (chan->indio_dev->info == NULL) {
 522                 ret = -ENODEV;
 523                 goto err_unlock;
 524         }
 525
 526         if (iio_channel_has_info(chan->channel, IIO_CHAN_INFO_PROCESSED)) {
 527                 ret = iio_channel_read(chan, val, NULL,
 528                                        IIO_CHAN_INFO_PROCESSED);
 529         } else {
 530                 ret = iio_channel_read(chan, val, NULL, IIO_CHAN_INFO_RAW);
 531                 if (ret < 0)
 532                         goto err_unlock;
 533                 ret = iio_convert_raw_to_processed_unlocked(chan, *val, val, 1);
 534         }
 535
 536 err_unlock:
 537         mutex_unlock(&chan->indio_dev->info_exist_lock);
 538
 539         return ret;
 540 }
 541 EXPORT_SYMBOL_GPL(iio_read_channel_processed);
 542
 543 int iio_read_channel_scale(struct iio_channel *chan, int *val, int *val2)
 544 {
 545         int ret;
 546
 547         mutex_lock(&chan->indio_dev->info_exist_lock);
 548         if (chan->indio_dev->info == NULL) {
 549                 ret = -ENODEV;
 550                 goto err_unlock;
 551         }
 552
 553         ret = iio_channel_read(chan, val, val2, IIO_CHAN_INFO_SCALE);
 554 err_unlock:
 555         mutex_unlock(&chan->indio_dev->info_exist_lock);
 556
 557         return ret;
 558 }
 559 EXPORT_SYMBOL_GPL(iio_read_channel_scale);
 560
 561 int iio_get_channel_type(struct iio_channel *chan, enum iio_chan_type *type)
 562 {
 563         int ret = 0;
 564         /* Need to verify underlying driver has not gone away */
 565
 566         mutex_lock(&chan->indio_dev->info_exist_lock);
 567         if (chan->indio_dev->info == NULL) {
 568                 ret = -ENODEV;
 569                 goto err_unlock;
 570         }
 571
 572         *type = chan->channel->type;
 573 err_unlock:
 574         mutex_unlock(&chan->indio_dev->info_exist_lock);
 575
 576         return ret;
 577 }
 578 EXPORT_SYMBOL_GPL(iio_get_channel_type);