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