tools/iio/iio_utils.c

   1 /* IIO - useful set of util functionality
   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 #include <string.h>
  10 #include <stdlib.h>
  11 #include <stdio.h>
  12 #include <stdint.h>
  13 #include <dirent.h>
  14 #include <errno.h>
  15 #include <ctype.h>
  16 #include "iio_utils.h"
  17
  18 const char *iio_dir = "/sys/bus/iio/devices/";
  19
  20 static char * const iio_direction[] = {
  21         "in",
  22         "out",
  23 };
  24
  25 /**
  26  * iioutils_break_up_name() - extract generic name from full channel name
  27  * @full_name: the full channel name
  28  * @generic_name: the output generic channel name
  29  *
  30  * Returns 0 on success, or a negative error code if string extraction failed.
  31  **/
  32 int iioutils_break_up_name(const char *full_name, char **generic_name)
  33 {
  34         char *current;
  35         char *w, *r;
  36         char *working, *prefix = "";
  37         int i, ret;
  38
  39         for (i = 0; i < ARRAY_SIZE(iio_direction); i++)
  40                 if (!strncmp(full_name, iio_direction[i],
  41                              strlen(iio_direction[i]))) {
  42                         prefix = iio_direction[i];
  43                         break;
  44                 }
  45
  46         current = strdup(full_name + strlen(prefix) + 1);
  47         if (!current)
  48                 return -ENOMEM;
  49
  50         working = strtok(current, "_\0");
  51         if (!working) {
  52                 free(current);
  53                 return -EINVAL;
  54         }
  55
  56         w = working;
  57         r = working;
  58
  59         while (*r != '\0') {
  60                 if (!isdigit(*r)) {
  61                         *w = *r;
  62                         w++;
  63                 }
  64
  65                 r++;
  66         }
  67         *w = '\0';
  68         ret = asprintf(generic_name, "%s_%s", prefix, working);
  69         free(current);
  70
  71         return (ret == -1) ? -ENOMEM : 0;
  72 }
  73
  74 /**
  75  * iioutils_get_type() - find and process _type attribute data
  76  * @is_signed: output whether channel is signed
  77  * @bytes: output how many bytes the channel storage occupies
  78  * @bits_used: output number of valid bits of data
  79  * @shift: output amount of bits to shift right data before applying bit mask
  80  * @mask: output a bit mask for the raw data
  81  * @be: output if data in big endian
  82  * @device_dir: the IIO device directory
  83  * @name: the channel name
  84  * @generic_name: the channel type name
  85  *
  86  * Returns a value >= 0 on success, otherwise a negative error code.
  87  **/
  88 int iioutils_get_type(unsigned *is_signed, unsigned *bytes, unsigned *bits_used,
  89                       unsigned *shift, uint64_t *mask, unsigned *be,
  90                       const char *device_dir, const char *name,
  91                       const char *generic_name)
  92 {
  93         FILE *sysfsfp;
  94         int ret;
  95         DIR *dp;
  96         char *scan_el_dir, *builtname, *builtname_generic, *filename = 0;
  97         char signchar, endianchar;
  98         unsigned padint;
  99         const struct dirent *ent;
 100
 101         ret = asprintf(&scan_el_dir, FORMAT_SCAN_ELEMENTS_DIR, device_dir);
 102         if (ret < 0)
 103                 return -ENOMEM;
 104
 105         ret = asprintf(&builtname, FORMAT_TYPE_FILE, name);
 106         if (ret < 0) {
 107                 ret = -ENOMEM;
 108                 goto error_free_scan_el_dir;
 109         }
 110         ret = asprintf(&builtname_generic, FORMAT_TYPE_FILE, generic_name);
 111         if (ret < 0) {
 112                 ret = -ENOMEM;
 113                 goto error_free_builtname;
 114         }
 115
 116         dp = opendir(scan_el_dir);
 117         if (!dp) {
 118                 ret = -errno;
 119                 goto error_free_builtname_generic;
 120         }
 121
 122         ret = -ENOENT;
 123         while (ent = readdir(dp), ent)
 124                 if ((strcmp(builtname, ent->d_name) == 0) ||
 125                     (strcmp(builtname_generic, ent->d_name) == 0)) {
 126                         ret = asprintf(&filename,
 127                                        "%s/%s", scan_el_dir, ent->d_name);
 128                         if (ret < 0) {
 129                                 ret = -ENOMEM;
 130                                 goto error_closedir;
 131                         }
 132
 133                         sysfsfp = fopen(filename, "r");
 134                         if (!sysfsfp) {
 135                                 ret = -errno;
 136                                 fprintf(stderr, "failed to open %s\n",
 137                                         filename);
 138                                 goto error_free_filename;
 139                         }
 140
 141                         ret = fscanf(sysfsfp,
 142                                      "%ce:%c%u/%u>>%u",
 143                                      &endianchar,
 144                                      &signchar,
 145                                      bits_used,
 146                                      &padint, shift);
 147                         if (ret < 0) {
 148                                 ret = -errno;
 149                                 fprintf(stderr,
 150                                         "failed to pass scan type description\n");
 151                                 goto error_close_sysfsfp;
 152                         } else if (ret != 5) {
 153                                 ret = -EIO;
 154                                 fprintf(stderr,
 155                                         "scan type description didn't match\n");
 156                                 goto error_close_sysfsfp;
 157                         }
 158
 159                         *be = (endianchar == 'b');
 160                         *bytes = padint / 8;
 161                         if (*bits_used == 64)
 162                                 *mask = ~(0ULL);
 163                         else
 164                                 *mask = (1ULL << *bits_used) - 1ULL;
 165
 166                         *is_signed = (signchar == 's');
 167                         if (fclose(sysfsfp)) {
 168                                 ret = -errno;
 169                                 fprintf(stderr, "Failed to close %s\n",
 170                                         filename);
 171                                 goto error_free_filename;
 172                         }
 173
 174                         sysfsfp = 0;
 175                         free(filename);
 176                         filename = 0;
 177
 178                         /*
 179                          * Avoid having a more generic entry overwriting
 180                          * the settings.
 181                          */
 182                         if (strcmp(builtname, ent->d_name) == 0)
 183                                 break;
 184                 }
 185
 186 error_close_sysfsfp:
 187         if (sysfsfp)
 188                 if (fclose(sysfsfp))
 189                         perror("iioutils_get_type(): Failed to close file");
 190
 191 error_free_filename:
 192         if (filename)
 193                 free(filename);
 194
 195 error_closedir:
 196         if (closedir(dp) == -1)
 197                 perror("iioutils_get_type(): Failed to close directory");
 198
 199 error_free_builtname_generic:
 200         free(builtname_generic);
 201 error_free_builtname:
 202         free(builtname);
 203 error_free_scan_el_dir:
 204         free(scan_el_dir);
 205
 206         return ret;
 207 }
 208
 209 /**
 210  * iioutils_get_param_float() - read a float value from a channel parameter
 211  * @output: output the float value
 212  * @param_name: the parameter name to read
 213  * @device_dir: the IIO device directory in sysfs
 214  * @name: the channel name
 215  * @generic_name: the channel type name
 216  *
 217  * Returns a value >= 0 on success, otherwise a negative error code.
 218  **/
 219 int iioutils_get_param_float(float *output, const char *param_name,
 220                              const char *device_dir, const char *name,
 221                              const char *generic_name)
 222 {
 223         FILE *sysfsfp;
 224         int ret;
 225         DIR *dp;
 226         char *builtname, *builtname_generic;
 227         char *filename = NULL;
 228         const struct dirent *ent;
 229
 230         ret = asprintf(&builtname, "%s_%s", name, param_name);
 231         if (ret < 0)
 232                 return -ENOMEM;
 233
 234         ret = asprintf(&builtname_generic,
 235                        "%s_%s", generic_name, param_name);
 236         if (ret < 0) {
 237                 ret = -ENOMEM;
 238                 goto error_free_builtname;
 239         }
 240
 241         dp = opendir(device_dir);
 242         if (!dp) {
 243                 ret = -errno;
 244                 goto error_free_builtname_generic;
 245         }
 246
 247         ret = -ENOENT;
 248         while (ent = readdir(dp), ent)
 249                 if ((strcmp(builtname, ent->d_name) == 0) ||
 250                     (strcmp(builtname_generic, ent->d_name) == 0)) {
 251                         ret = asprintf(&filename,
 252                                        "%s/%s", device_dir, ent->d_name);
 253                         if (ret < 0) {
 254                                 ret = -ENOMEM;
 255                                 goto error_closedir;
 256                         }
 257
 258                         sysfsfp = fopen(filename, "r");
 259                         if (!sysfsfp) {
 260                                 ret = -errno;
 261                                 goto error_free_filename;
 262                         }
 263
 264                         errno = 0;
 265                         if (fscanf(sysfsfp, "%f", output) != 1)
 266                                 ret = errno ? -errno : -ENODATA;
 267
 268                         break;
 269                 }
 270 error_free_filename:
 271         if (filename)
 272                 free(filename);
 273
 274 error_closedir:
 275         if (closedir(dp) == -1)
 276                 perror("iioutils_get_param_float(): Failed to close directory");
 277
 278 error_free_builtname_generic:
 279         free(builtname_generic);
 280 error_free_builtname:
 281         free(builtname);
 282
 283         return ret;
 284 }
 285
 286 /**
 287  * bsort_channel_array_by_index() - sort the array in index order
 288  * @ci_array: the iio_channel_info array to be sorted
 289  * @cnt: the amount of array elements
 290  **/
 291
 292 void bsort_channel_array_by_index(struct iio_channel_info *ci_array, int cnt)
 293 {
 294         struct iio_channel_info temp;
 295         int x, y;
 296
 297         for (x = 0; x < cnt; x++)
 298                 for (y = 0; y < (cnt - 1); y++)
 299                         if (ci_array[y].index > ci_array[y + 1].index) {
 300                                 temp = ci_array[y + 1];
 301                                 ci_array[y + 1] = ci_array[y];
 302                                 ci_array[y] = temp;
 303                         }
 304 }
 305
 306 /**
 307  * build_channel_array() - function to figure out what channels are present
 308  * @device_dir: the IIO device directory in sysfs
 309  * @ci_array: output the resulting array of iio_channel_info
 310  * @counter: output the amount of array elements
 311  *
 312  * Returns 0 on success, otherwise a negative error code.
 313  **/
 314 int build_channel_array(const char *device_dir,
 315                         struct iio_channel_info **ci_array, int *counter)
 316 {
 317         DIR *dp;
 318         FILE *sysfsfp;
 319         int count = 0, i;
 320         struct iio_channel_info *current;
 321         int ret;
 322         const struct dirent *ent;
 323         char *scan_el_dir;
 324         char *filename;
 325
 326         *counter = 0;
 327         ret = asprintf(&scan_el_dir, FORMAT_SCAN_ELEMENTS_DIR, device_dir);
 328         if (ret < 0)
 329                 return -ENOMEM;
 330
 331         dp = opendir(scan_el_dir);
 332         if (!dp) {
 333                 ret = -errno;
 334                 goto error_free_name;
 335         }
 336
 337         while (ent = readdir(dp), ent)
 338                 if (strcmp(ent->d_name + strlen(ent->d_name) - strlen("_en"),
 339                            "_en") == 0) {
 340                         ret = asprintf(&filename,
 341                                        "%s/%s", scan_el_dir, ent->d_name);
 342                         if (ret < 0) {
 343                                 ret = -ENOMEM;
 344                                 goto error_close_dir;
 345                         }
 346
 347                         sysfsfp = fopen(filename, "r");
 348                         if (!sysfsfp) {
 349                                 ret = -errno;
 350                                 free(filename);
 351                                 goto error_close_dir;
 352                         }
 353
 354                         errno = 0;
 355                         if (fscanf(sysfsfp, "%i", &ret) != 1) {
 356                                 ret = errno ? -errno : -ENODATA;
 357                                 if (fclose(sysfsfp))
 358                                         perror("build_channel_array(): Failed to close file");
 359
 360                                 free(filename);
 361                                 goto error_close_dir;
 362                         }
 363                         if (ret == 1)
 364                                 (*counter)++;
 365
 366                         if (fclose(sysfsfp)) {
 367                                 ret = -errno;
 368                                 free(filename);
 369                                 goto error_close_dir;
 370                         }
 371
 372                         free(filename);
 373                 }
 374
 375         *ci_array = malloc(sizeof(**ci_array) * (*counter));
 376         if (!*ci_array) {
 377                 ret = -ENOMEM;
 378                 goto error_close_dir;
 379         }
 380
 381         seekdir(dp, 0);
 382         while (ent = readdir(dp), ent) {
 383                 if (strcmp(ent->d_name + strlen(ent->d_name) - strlen("_en"),
 384                            "_en") == 0) {
 385                         int current_enabled = 0;
 386
 387                         current = &(*ci_array)[count++];
 388                         ret = asprintf(&filename,
 389                                        "%s/%s", scan_el_dir, ent->d_name);
 390                         if (ret < 0) {
 391                                 ret = -ENOMEM;
 392                                 /* decrement count to avoid freeing name */
 393                                 count--;
 394                                 goto error_cleanup_array;
 395                         }
 396
 397                         sysfsfp = fopen(filename, "r");
 398                         if (!sysfsfp) {
 399                                 ret = -errno;
 400                                 free(filename);
 401                                 count--;
 402                                 goto error_cleanup_array;
 403                         }
 404
 405                         errno = 0;
 406                         if (fscanf(sysfsfp, "%i", &current_enabled) != 1) {
 407                                 ret = errno ? -errno : -ENODATA;
 408                                 free(filename);
 409                                 count--;
 410                                 goto error_cleanup_array;
 411                         }
 412
 413                         if (fclose(sysfsfp)) {
 414                                 ret = -errno;
 415                                 free(filename);
 416                                 count--;
 417                                 goto error_cleanup_array;
 418                         }
 419
 420                         if (!current_enabled) {
 421                                 free(filename);
 422                                 count--;
 423                                 continue;
 424                         }
 425
 426                         current->scale = 1.0;
 427                         current->offset = 0;
 428                         current->name = strndup(ent->d_name,
 429                                                 strlen(ent->d_name) -
 430                                                 strlen("_en"));
 431                         if (!current->name) {
 432                                 free(filename);
 433                                 ret = -ENOMEM;
 434                                 count--;
 435                                 goto error_cleanup_array;
 436                         }
 437
 438                         /* Get the generic and specific name elements */
 439                         ret = iioutils_break_up_name(current->name,
 440                                                      &current->generic_name);
 441                         if (ret) {
 442                                 free(filename);
 443                                 free(current->name);
 444                                 count--;
 445                                 goto error_cleanup_array;
 446                         }
 447
 448                         ret = asprintf(&filename,
 449                                        "%s/%s_index",
 450                                        scan_el_dir,
 451                                        current->name);
 452                         if (ret < 0) {
 453                                 free(filename);
 454                                 ret = -ENOMEM;
 455                                 goto error_cleanup_array;
 456                         }
 457
 458                         sysfsfp = fopen(filename, "r");
 459                         if (!sysfsfp) {
 460                                 ret = -errno;
 461                                 fprintf(stderr, "failed to open %s\n",
 462                                         filename);
 463                                 free(filename);
 464                                 goto error_cleanup_array;
 465                         }
 466
 467                         errno = 0;
 468                         if (fscanf(sysfsfp, "%u", &current->index) != 1) {
 469                                 ret = errno ? -errno : -ENODATA;
 470                                 if (fclose(sysfsfp))
 471                                         perror("build_channel_array(): Failed to close file");
 472
 473                                 free(filename);
 474                                 goto error_cleanup_array;
 475                         }
 476
 477                         if (fclose(sysfsfp)) {
 478                                 ret = -errno;
 479                                 free(filename);
 480                                 goto error_cleanup_array;
 481                         }
 482
 483                         free(filename);
 484                         /* Find the scale */
 485                         ret = iioutils_get_param_float(&current->scale,
 486                                                        "scale",
 487                                                        device_dir,
 488                                                        current->name,
 489                                                        current->generic_name);
 490                         if ((ret < 0) && (ret != -ENOENT))
 491                                 goto error_cleanup_array;
 492
 493                         ret = iioutils_get_param_float(&current->offset,
 494                                                        "offset",
 495                                                        device_dir,
 496                                                        current->name,
 497                                                        current->generic_name);
 498                         if ((ret < 0) && (ret != -ENOENT))
 499                                 goto error_cleanup_array;
 500
 501                         ret = iioutils_get_type(&current->is_signed,
 502                                                 &current->bytes,
 503                                                 &current->bits_used,
 504                                                 &current->shift,
 505                                                 &current->mask,
 506                                                 &current->be,
 507                                                 device_dir,
 508                                                 current->name,
 509                                                 current->generic_name);
 510                         if (ret < 0)
 511                                 goto error_cleanup_array;
 512                 }
 513         }
 514
 515         if (closedir(dp) == -1) {
 516                 ret = -errno;
 517                 goto error_cleanup_array;
 518         }
 519
 520         free(scan_el_dir);
 521         /* reorder so that the array is in index order */
 522         bsort_channel_array_by_index(*ci_array, *counter);
 523
 524         return 0;
 525
 526 error_cleanup_array:
 527         for (i = count - 1;  i >= 0; i--) {
 528                 free((*ci_array)[i].name);
 529                 free((*ci_array)[i].generic_name);
 530         }
 531         free(*ci_array);
 532         *ci_array = NULL;
 533         *counter = 0;
 534 error_close_dir:
 535         if (dp)
 536                 if (closedir(dp) == -1)
 537                         perror("build_channel_array(): Failed to close dir");
 538
 539 error_free_name:
 540         free(scan_el_dir);
 541
 542         return ret;
 543 }
 544
 545 static int calc_digits(int num)
 546 {
 547         int count = 0;
 548
 549         while (num != 0) {
 550                 num /= 10;
 551                 count++;
 552         }
 553
 554         return count;
 555 }
 556
 557 /**
 558  * find_type_by_name() - function to match top level types by name
 559  * @name: top level type instance name
 560  * @type: the type of top level instance being searched
 561  *
 562  * Returns the device number of a matched IIO device on success, otherwise a
 563  * negative error code.
 564  * Typical types this is used for are device and trigger.
 565  **/
 566 int find_type_by_name(const char *name, const char *type)
 567 {
 568         const struct dirent *ent;
 569         int number, numstrlen, ret;
 570
 571         FILE *namefp;
 572         DIR *dp;
 573         char thisname[IIO_MAX_NAME_LENGTH];
 574         char *filename;
 575
 576         dp = opendir(iio_dir);
 577         if (!dp) {
 578                 fprintf(stderr, "No industrialio devices available\n");
 579                 return -ENODEV;
 580         }
 581
 582         while (ent = readdir(dp), ent) {
 583                 if (strcmp(ent->d_name, ".") != 0 &&
 584                     strcmp(ent->d_name, "..") != 0 &&
 585                     strlen(ent->d_name) > strlen(type) &&
 586                     strncmp(ent->d_name, type, strlen(type)) == 0) {
 587                         errno = 0;
 588                         ret = sscanf(ent->d_name + strlen(type), "%d", &number);
 589                         if (ret < 0) {
 590                                 ret = -errno;
 591                                 fprintf(stderr,
 592                                         "failed to read element number\n");
 593                                 goto error_close_dir;
 594                         } else if (ret != 1) {
 595                                 ret = -EIO;
 596                                 fprintf(stderr,
 597                                         "failed to match element number\n");
 598                                 goto error_close_dir;
 599                         }
 600
 601                         numstrlen = calc_digits(number);
 602                         /* verify the next character is not a colon */
 603                         if (strncmp(ent->d_name + strlen(type) + numstrlen,
 604                             ":", 1) != 0) {
 605                                 filename = malloc(strlen(iio_dir) + strlen(type)
 606                                                   + numstrlen + 6);
 607                                 if (!filename) {
 608                                         ret = -ENOMEM;
 609                                         goto error_close_dir;
 610                                 }
 611
 612                                 ret = sprintf(filename, "%s%s%d/name", iio_dir,
 613                                               type, number);
 614                                 if (ret < 0) {
 615                                         free(filename);
 616                                         goto error_close_dir;
 617                                 }
 618
 619                                 namefp = fopen(filename, "r");
 620                                 if (!namefp) {
 621                                         free(filename);
 622                                         continue;
 623                                 }
 624
 625                                 free(filename);
 626                                 errno = 0;
 627                                 if (fscanf(namefp, "%s", thisname) != 1) {
 628                                         ret = errno ? -errno : -ENODATA;
 629                                         goto error_close_dir;
 630                                 }
 631
 632                                 if (fclose(namefp)) {
 633                                         ret = -errno;
 634                                         goto error_close_dir;
 635                                 }
 636
 637                                 if (strcmp(name, thisname) == 0) {
 638                                         if (closedir(dp) == -1)
 639                                                 return -errno;
 640
 641                                         return number;
 642                                 }
 643                         }
 644                 }
 645         }
 646         if (closedir(dp) == -1)
 647                 return -errno;
 648
 649         return -ENODEV;
 650
 651 error_close_dir:
 652         if (closedir(dp) == -1)
 653                 perror("find_type_by_name(): Failed to close directory");
 654
 655         return ret;
 656 }
 657
 658 static int _write_sysfs_int(const char *filename, const char *basedir, int val,
 659                             int verify)
 660 {
 661         int ret = 0;
 662         FILE *sysfsfp;
 663         int test;
 664         char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
 665
 666         if (!temp)
 667                 return -ENOMEM;
 668
 669         ret = sprintf(temp, "%s/%s", basedir, filename);
 670         if (ret < 0)
 671                 goto error_free;
 672
 673         sysfsfp = fopen(temp, "w");
 674         if (!sysfsfp) {
 675                 ret = -errno;
 676                 fprintf(stderr, "failed to open %s\n", temp);
 677                 goto error_free;
 678         }
 679
 680         ret = fprintf(sysfsfp, "%d", val);
 681         if (ret < 0) {
 682                 if (fclose(sysfsfp))
 683                         perror("_write_sysfs_int(): Failed to close dir");
 684
 685                 goto error_free;
 686         }
 687
 688         if (fclose(sysfsfp)) {
 689                 ret = -errno;
 690                 goto error_free;
 691         }
 692
 693         if (verify) {
 694                 sysfsfp = fopen(temp, "r");
 695                 if (!sysfsfp) {
 696                         ret = -errno;
 697                         fprintf(stderr, "failed to open %s\n", temp);
 698                         goto error_free;
 699                 }
 700
 701                 if (fscanf(sysfsfp, "%d", &test) != 1) {
 702                         ret = errno ? -errno : -ENODATA;
 703                         if (fclose(sysfsfp))
 704                                 perror("_write_sysfs_int(): Failed to close dir");
 705
 706                         goto error_free;
 707                 }
 708
 709                 if (fclose(sysfsfp)) {
 710                         ret = -errno;
 711                         goto error_free;
 712                 }
 713
 714                 if (test != val) {
 715                         fprintf(stderr,
 716                                 "Possible failure in int write %d to %s/%s\n",
 717                                 val, basedir, filename);
 718                         ret = -1;
 719                 }
 720         }
 721
 722 error_free:
 723         free(temp);
 724         return ret;
 725 }
 726
 727 /**
 728  * write_sysfs_int() - write an integer value to a sysfs file
 729  * @filename: name of the file to write to
 730  * @basedir: the sysfs directory in which the file is to be found
 731  * @val: integer value to write to file
 732  *
 733  * Returns a value >= 0 on success, otherwise a negative error code.
 734  **/
 735 int write_sysfs_int(const char *filename, const char *basedir, int val)
 736 {
 737         return _write_sysfs_int(filename, basedir, val, 0);
 738 }
 739
 740 /**
 741  * write_sysfs_int_and_verify() - write an integer value to a sysfs file
 742  *                                and verify
 743  * @filename: name of the file to write to
 744  * @basedir: the sysfs directory in which the file is to be found
 745  * @val: integer value to write to file
 746  *
 747  * Returns a value >= 0 on success, otherwise a negative error code.
 748  **/
 749 int write_sysfs_int_and_verify(const char *filename, const char *basedir,
 750                                int val)
 751 {
 752         return _write_sysfs_int(filename, basedir, val, 1);
 753 }
 754
 755 static int _write_sysfs_string(const char *filename, const char *basedir,
 756                                const char *val, int verify)
 757 {
 758         int ret = 0;
 759         FILE  *sysfsfp;
 760         char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
 761
 762         if (!temp) {
 763                 fprintf(stderr, "Memory allocation failed\n");
 764                 return -ENOMEM;
 765         }
 766
 767         ret = sprintf(temp, "%s/%s", basedir, filename);
 768         if (ret < 0)
 769                 goto error_free;
 770
 771         sysfsfp = fopen(temp, "w");
 772         if (!sysfsfp) {
 773                 ret = -errno;
 774                 fprintf(stderr, "Could not open %s\n", temp);
 775                 goto error_free;
 776         }
 777
 778         ret = fprintf(sysfsfp, "%s", val);
 779         if (ret < 0) {
 780                 if (fclose(sysfsfp))
 781                         perror("_write_sysfs_string(): Failed to close dir");
 782
 783                 goto error_free;
 784         }
 785
 786         if (fclose(sysfsfp)) {
 787                 ret = -errno;
 788                 goto error_free;
 789         }
 790
 791         if (verify) {
 792                 sysfsfp = fopen(temp, "r");
 793                 if (!sysfsfp) {
 794                         ret = -errno;
 795                         fprintf(stderr, "Could not open file to verify\n");
 796                         goto error_free;
 797                 }
 798
 799                 if (fscanf(sysfsfp, "%s", temp) != 1) {
 800                         ret = errno ? -errno : -ENODATA;
 801                         if (fclose(sysfsfp))
 802                                 perror("_write_sysfs_string(): Failed to close dir");
 803
 804                         goto error_free;
 805                 }
 806
 807                 if (fclose(sysfsfp)) {
 808                         ret = -errno;
 809                         goto error_free;
 810                 }
 811
 812                 if (strcmp(temp, val) != 0) {
 813                         fprintf(stderr,
 814                                 "Possible failure in string write of %s "
 815                                 "Should be %s written to %s/%s\n", temp, val,
 816                                 basedir, filename);
 817                         ret = -1;
 818                 }
 819         }
 820
 821 error_free:
 822         free(temp);
 823
 824         return ret;
 825 }
 826
 827 /**
 828  * write_sysfs_string_and_verify() - string write, readback and verify
 829  * @filename: name of file to write to
 830  * @basedir: the sysfs directory in which the file is to be found
 831  * @val: the string to write
 832  *
 833  * Returns a value >= 0 on success, otherwise a negative error code.
 834  **/
 835 int write_sysfs_string_and_verify(const char *filename, const char *basedir,
 836                                   const char *val)
 837 {
 838         return _write_sysfs_string(filename, basedir, val, 1);
 839 }
 840
 841 /**
 842  * write_sysfs_string() - write string to a sysfs file
 843  * @filename: name of file to write to
 844  * @basedir: the sysfs directory in which the file is to be found
 845  * @val: the string to write
 846  *
 847  * Returns a value >= 0 on success, otherwise a negative error code.
 848  **/
 849 int write_sysfs_string(const char *filename, const char *basedir,
 850                        const char *val)
 851 {
 852         return _write_sysfs_string(filename, basedir, val, 0);
 853 }
 854
 855 /**
 856  * read_sysfs_posint() - read an integer value from file
 857  * @filename: name of file to read from
 858  * @basedir: the sysfs directory in which the file is to be found
 859  *
 860  * Returns the read integer value >= 0 on success, otherwise a negative error
 861  * code.
 862  **/
 863 int read_sysfs_posint(const char *filename, const char *basedir)
 864 {
 865         int ret;
 866         FILE  *sysfsfp;
 867         char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
 868
 869         if (!temp) {
 870                 fprintf(stderr, "Memory allocation failed");
 871                 return -ENOMEM;
 872         }
 873
 874         ret = sprintf(temp, "%s/%s", basedir, filename);
 875         if (ret < 0)
 876                 goto error_free;
 877
 878         sysfsfp = fopen(temp, "r");
 879         if (!sysfsfp) {
 880                 ret = -errno;
 881                 goto error_free;
 882         }
 883
 884         errno = 0;
 885         if (fscanf(sysfsfp, "%d\n", &ret) != 1) {
 886                 ret = errno ? -errno : -ENODATA;
 887                 if (fclose(sysfsfp))
 888                         perror("read_sysfs_posint(): Failed to close dir");
 889
 890                 goto error_free;
 891         }
 892
 893         if (fclose(sysfsfp))
 894                 ret = -errno;
 895
 896 error_free:
 897         free(temp);
 898
 899         return ret;
 900 }
 901
 902 /**
 903  * read_sysfs_float() - read a float value from file
 904  * @filename: name of file to read from
 905  * @basedir: the sysfs directory in which the file is to be found
 906  * @val: output the read float value
 907  *
 908  * Returns a value >= 0 on success, otherwise a negative error code.
 909  **/
 910 int read_sysfs_float(const char *filename, const char *basedir, float *val)
 911 {
 912         int ret = 0;
 913         FILE  *sysfsfp;
 914         char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
 915
 916         if (!temp) {
 917                 fprintf(stderr, "Memory allocation failed");
 918                 return -ENOMEM;
 919         }
 920
 921         ret = sprintf(temp, "%s/%s", basedir, filename);
 922         if (ret < 0)
 923                 goto error_free;
 924
 925         sysfsfp = fopen(temp, "r");
 926         if (!sysfsfp) {
 927                 ret = -errno;
 928                 goto error_free;
 929         }
 930
 931         errno = 0;
 932         if (fscanf(sysfsfp, "%f\n", val) != 1) {
 933                 ret = errno ? -errno : -ENODATA;
 934                 if (fclose(sysfsfp))
 935                         perror("read_sysfs_float(): Failed to close dir");
 936
 937                 goto error_free;
 938         }
 939
 940         if (fclose(sysfsfp))
 941                 ret = -errno;
 942
 943 error_free:
 944         free(temp);
 945
 946         return ret;
 947 }
 948
 949 /**
 950  * read_sysfs_string() - read a string from file
 951  * @filename: name of file to read from
 952  * @basedir: the sysfs directory in which the file is to be found
 953  * @str: output the read string
 954  *
 955  * Returns a value >= 0 on success, otherwise a negative error code.
 956  **/
 957 int read_sysfs_string(const char *filename, const char *basedir, char *str)
 958 {
 959         int ret = 0;
 960         FILE  *sysfsfp;
 961         char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
 962
 963         if (!temp) {
 964                 fprintf(stderr, "Memory allocation failed");
 965                 return -ENOMEM;
 966         }
 967
 968         ret = sprintf(temp, "%s/%s", basedir, filename);
 969         if (ret < 0)
 970                 goto error_free;
 971
 972         sysfsfp = fopen(temp, "r");
 973         if (!sysfsfp) {
 974                 ret = -errno;
 975                 goto error_free;
 976         }
 977
 978         errno = 0;
 979         if (fscanf(sysfsfp, "%s\n", str) != 1) {
 980                 ret = errno ? -errno : -ENODATA;
 981                 if (fclose(sysfsfp))
 982                         perror("read_sysfs_string(): Failed to close dir");
 983
 984                 goto error_free;
 985         }
 986
 987         if (fclose(sysfsfp))
 988                 ret = -errno;
 989
 990 error_free:
 991         free(temp);
 992
 993         return ret;
 994 }