tools/iio/generic_buffer.c

   1 /* Industrialio buffer test code.
   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  * This program is primarily intended as an example application.
  10  * Reads the current buffer setup from sysfs and starts a short capture
  11  * from the specified device, pretty printing the result after appropriate
  12  * conversion.
  13  *
  14  * Command line parameters
  15  * generic_buffer -n <device_name> -t <trigger_name>
  16  * If trigger name is not specified the program assumes you want a dataready
  17  * trigger associated with the device and goes looking for it.
  18  *
  19  */
  20
  21 #include <unistd.h>
  22 #include <stdlib.h>
  23 #include <dirent.h>
  24 #include <fcntl.h>
  25 #include <stdio.h>
  26 #include <errno.h>
  27 #include <sys/stat.h>
  28 #include <sys/dir.h>
  29 #include <linux/types.h>
  30 #include <string.h>
  31 #include <poll.h>
  32 #include <endian.h>
  33 #include <getopt.h>
  34 #include <inttypes.h>
  35 #include "iio_utils.h"
  36
  37 /**
  38  * enum autochan - state for the automatic channel enabling mechanism
  39  */
  40 enum autochan {
  41         AUTOCHANNELS_DISABLED,
  42         AUTOCHANNELS_ENABLED,
  43         AUTOCHANNELS_ACTIVE,
  44 };
  45
  46 /**
  47  * size_from_channelarray() - calculate the storage size of a scan
  48  * @channels:           the channel info array
  49  * @num_channels:       number of channels
  50  *
  51  * Has the side effect of filling the channels[i].location values used
  52  * in processing the buffer output.
  53  **/
  54 int size_from_channelarray(struct iio_channel_info *channels, int num_channels)
  55 {
  56         int bytes = 0;
  57         int i = 0;
  58
  59         while (i < num_channels) {
  60                 if (bytes % channels[i].bytes == 0)
  61                         channels[i].location = bytes;
  62                 else
  63                         channels[i].location = bytes - bytes % channels[i].bytes
  64                                                + channels[i].bytes;
  65
  66                 bytes = channels[i].location + channels[i].bytes;
  67                 i++;
  68         }
  69
  70         return bytes;
  71 }
  72
  73 void print1byte(uint8_t input, struct iio_channel_info *info)
  74 {
  75         /*
  76          * Shift before conversion to avoid sign extension
  77          * of left aligned data
  78          */
  79         input >>= info->shift;
  80         input &= info->mask;
  81         if (info->is_signed) {
  82                 int8_t val = (int8_t)(input << (8 - info->bits_used)) >>
  83                              (8 - info->bits_used);
  84                 printf("%05f ", ((float)val + info->offset) * info->scale);
  85         } else {
  86                 printf("%05f ", ((float)input + info->offset) * info->scale);
  87         }
  88 }
  89
  90 void print2byte(uint16_t input, struct iio_channel_info *info)
  91 {
  92         /* First swap if incorrect endian */
  93         if (info->be)
  94                 input = be16toh(input);
  95         else
  96                 input = le16toh(input);
  97
  98         /*
  99          * Shift before conversion to avoid sign extension
 100          * of left aligned data
 101          */
 102         input >>= info->shift;
 103         input &= info->mask;
 104         if (info->is_signed) {
 105                 int16_t val = (int16_t)(input << (16 - info->bits_used)) >>
 106                               (16 - info->bits_used);
 107                 printf("%05f ", ((float)val + info->offset) * info->scale);
 108         } else {
 109                 printf("%05f ", ((float)input + info->offset) * info->scale);
 110         }
 111 }
 112
 113 void print4byte(uint32_t input, struct iio_channel_info *info)
 114 {
 115         /* First swap if incorrect endian */
 116         if (info->be)
 117                 input = be32toh(input);
 118         else
 119                 input = le32toh(input);
 120
 121         /*
 122          * Shift before conversion to avoid sign extension
 123          * of left aligned data
 124          */
 125         input >>= info->shift;
 126         input &= info->mask;
 127         if (info->is_signed) {
 128                 int32_t val = (int32_t)(input << (32 - info->bits_used)) >>
 129                               (32 - info->bits_used);
 130                 printf("%05f ", ((float)val + info->offset) * info->scale);
 131         } else {
 132                 printf("%05f ", ((float)input + info->offset) * info->scale);
 133         }
 134 }
 135
 136 void print8byte(uint64_t input, struct iio_channel_info *info)
 137 {
 138         /* First swap if incorrect endian */
 139         if (info->be)
 140                 input = be64toh(input);
 141         else
 142                 input = le64toh(input);
 143
 144         /*
 145          * Shift before conversion to avoid sign extension
 146          * of left aligned data
 147          */
 148         input >>= info->shift;
 149         input &= info->mask;
 150         if (info->is_signed) {
 151                 int64_t val = (int64_t)(input << (64 - info->bits_used)) >>
 152                               (64 - info->bits_used);
 153                 /* special case for timestamp */
 154                 if (info->scale == 1.0f && info->offset == 0.0f)
 155                         printf("%" PRId64 " ", val);
 156                 else
 157                         printf("%05f ",
 158                                ((float)val + info->offset) * info->scale);
 159         } else {
 160                 printf("%05f ", ((float)input + info->offset) * info->scale);
 161         }
 162 }
 163
 164 /**
 165  * process_scan() - print out the values in SI units
 166  * @data:               pointer to the start of the scan
 167  * @channels:           information about the channels.
 168  *                      Note: size_from_channelarray must have been called first
 169  *                            to fill the location offsets.
 170  * @num_channels:       number of channels
 171  **/
 172 void process_scan(char *data,
 173                   struct iio_channel_info *channels,
 174                   int num_channels)
 175 {
 176         int k;
 177
 178         for (k = 0; k < num_channels; k++)
 179                 switch (channels[k].bytes) {
 180                         /* only a few cases implemented so far */
 181                 case 1:
 182                         print1byte(*(uint8_t *)(data + channels[k].location),
 183                                    &channels[k]);
 184                         break;
 185                 case 2:
 186                         print2byte(*(uint16_t *)(data + channels[k].location),
 187                                    &channels[k]);
 188                         break;
 189                 case 4:
 190                         print4byte(*(uint32_t *)(data + channels[k].location),
 191                                    &channels[k]);
 192                         break;
 193                 case 8:
 194                         print8byte(*(uint64_t *)(data + channels[k].location),
 195                                    &channels[k]);
 196                         break;
 197                 default:
 198                         break;
 199                 }
 200         printf("\n");
 201 }
 202
 203 static int enable_disable_all_channels(char *dev_dir_name, int enable)
 204 {
 205         const struct dirent *ent;
 206         char scanelemdir[256];
 207         DIR *dp;
 208         int ret;
 209
 210         snprintf(scanelemdir, sizeof(scanelemdir),
 211                  FORMAT_SCAN_ELEMENTS_DIR, dev_dir_name);
 212         scanelemdir[sizeof(scanelemdir)-1] = '\0';
 213
 214         dp = opendir(scanelemdir);
 215         if (!dp) {
 216                 fprintf(stderr, "Enabling/disabling channels: can't open %s\n",
 217                         scanelemdir);
 218                 return -EIO;
 219         }
 220
 221         ret = -ENOENT;
 222         while (ent = readdir(dp), ent) {
 223                 if (iioutils_check_suffix(ent->d_name, "_en")) {
 224                         printf("%sabling: %s\n",
 225                                enable ? "En" : "Dis",
 226                                ent->d_name);
 227                         ret = write_sysfs_int(ent->d_name, scanelemdir,
 228                                               enable);
 229                         if (ret < 0)
 230                                 fprintf(stderr, "Failed to enable/disable %s\n",
 231                                         ent->d_name);
 232                 }
 233         }
 234
 235         if (closedir(dp) == -1) {
 236                 perror("Enabling/disabling channels: "
 237                        "Failed to close directory");
 238                 return -errno;
 239         }
 240         return 0;
 241 }
 242
 243 void print_usage(void)
 244 {
 245         fprintf(stderr, "Usage: generic_buffer [options]...\n"
 246                 "Capture, convert and output data from IIO device buffer\n"
 247                 "  -a         Auto-activate all available channels\n"
 248                 "  -c <n>     Do n conversions\n"
 249                 "  -e         Disable wait for event (new data)\n"
 250                 "  -g         Use trigger-less mode\n"
 251                 "  -l <n>     Set buffer length to n samples\n"
 252                 "  -n <name>  Set device name (mandatory)\n"
 253                 "  -t <name>  Set trigger name\n"
 254                 "  -w <n>     Set delay between reads in us (event-less mode)\n");
 255 }
 256
 257 int main(int argc, char **argv)
 258 {
 259         unsigned long num_loops = 2;
 260         unsigned long timedelay = 1000000;
 261         unsigned long buf_len = 128;
 262
 263         int ret, c, i, j, toread;
 264         int fp;
 265
 266         int num_channels;
 267         char *trigger_name = NULL, *device_name = NULL;
 268         char *dev_dir_name, *buf_dir_name;
 269
 270         int datardytrigger = 1;
 271         char *data;
 272         ssize_t read_size;
 273         int dev_num, trig_num;
 274         char *buffer_access;
 275         int scan_size;
 276         int noevents = 0;
 277         int notrigger = 0;
 278         enum autochan autochannels = AUTOCHANNELS_DISABLED;
 279         char *dummy;
 280
 281         struct iio_channel_info *channels;
 282
 283         while ((c = getopt(argc, argv, "ac:egl:n:t:w:")) != -1) {
 284                 switch (c) {
 285                 case 'a':
 286                         autochannels = AUTOCHANNELS_ENABLED;
 287                         break;
 288                 case 'c':
 289                         errno = 0;
 290                         num_loops = strtoul(optarg, &dummy, 10);
 291                         if (errno)
 292                                 return -errno;
 293
 294                         break;
 295                 case 'e':
 296                         noevents = 1;
 297                         break;
 298                 case 'g':
 299                         notrigger = 1;
 300                         break;
 301                 case 'l':
 302                         errno = 0;
 303                         buf_len = strtoul(optarg, &dummy, 10);
 304                         if (errno)
 305                                 return -errno;
 306
 307                         break;
 308                 case 'n':
 309                         device_name = optarg;
 310                         break;
 311                 case 't':
 312                         trigger_name = optarg;
 313                         datardytrigger = 0;
 314                         break;
 315                 case 'w':
 316                         errno = 0;
 317                         timedelay = strtoul(optarg, &dummy, 10);
 318                         if (errno)
 319                                 return -errno;
 320                         break;
 321                 case '?':
 322                         print_usage();
 323                         return -1;
 324                 }
 325         }
 326
 327         if (!device_name) {
 328                 fprintf(stderr, "Device name not set\n");
 329                 print_usage();
 330                 return -1;
 331         }
 332
 333         /* Find the device requested */
 334         dev_num = find_type_by_name(device_name, "iio:device");
 335         if (dev_num < 0) {
 336                 fprintf(stderr, "Failed to find the %s\n", device_name);
 337                 return dev_num;
 338         }
 339
 340         printf("iio device number being used is %d\n", dev_num);
 341
 342         ret = asprintf(&dev_dir_name, "%siio:device%d", iio_dir, dev_num);
 343         if (ret < 0)
 344                 return -ENOMEM;
 345
 346         if (!notrigger) {
 347                 if (!trigger_name) {
 348                         /*
 349                          * Build the trigger name. If it is device associated
 350                          * its name is <device_name>_dev[n] where n matches
 351                          * the device number found above.
 352                          */
 353                         ret = asprintf(&trigger_name,
 354                                        "%s-dev%d", device_name, dev_num);
 355                         if (ret < 0) {
 356                                 ret = -ENOMEM;
 357                                 goto error_free_dev_dir_name;
 358                         }
 359                 }
 360
 361                 /* Look for this "-devN" trigger */
 362                 trig_num = find_type_by_name(trigger_name, "trigger");
 363                 if (trig_num < 0) {
 364                         /* OK try the simpler "-trigger" suffix instead */
 365                         free(trigger_name);
 366                         ret = asprintf(&trigger_name,
 367                                        "%s-trigger", device_name);
 368                         if (ret < 0) {
 369                                 ret = -ENOMEM;
 370                                 goto error_free_dev_dir_name;
 371                         }
 372                 }
 373
 374                 trig_num = find_type_by_name(trigger_name, "trigger");
 375                 if (trig_num < 0) {
 376                         fprintf(stderr, "Failed to find the trigger %s\n",
 377                                 trigger_name);
 378                         ret = trig_num;
 379                         goto error_free_triggername;
 380                 }
 381
 382                 printf("iio trigger number being used is %d\n", trig_num);
 383         } else {
 384                 printf("trigger-less mode selected\n");
 385         }
 386
 387         /*
 388          * Parse the files in scan_elements to identify what channels are
 389          * present
 390          */
 391         ret = build_channel_array(dev_dir_name, &channels, &num_channels);
 392         if (ret) {
 393                 fprintf(stderr, "Problem reading scan element information\n"
 394                         "diag %s\n", dev_dir_name);
 395                 goto error_free_triggername;
 396         }
 397         if (num_channels && autochannels == AUTOCHANNELS_ENABLED) {
 398                 fprintf(stderr, "Auto-channels selected but some channels "
 399                         "are already activated in sysfs\n");
 400                 fprintf(stderr, "Proceeding without activating any channels\n");
 401         }
 402
 403         if (!num_channels && autochannels == AUTOCHANNELS_ENABLED) {
 404                 fprintf(stderr,
 405                         "No channels are enabled, enabling all channels\n");
 406
 407                 ret = enable_disable_all_channels(dev_dir_name, 1);
 408                 if (ret) {
 409                         fprintf(stderr, "Failed to enable all channels\n");
 410                         goto error_free_triggername;
 411                 }
 412
 413                 /* This flags that we need to disable the channels again */
 414                 autochannels = AUTOCHANNELS_ACTIVE;
 415
 416                 ret = build_channel_array(dev_dir_name, &channels,
 417                                           &num_channels);
 418                 if (ret) {
 419                         fprintf(stderr, "Problem reading scan element "
 420                                 "information\n"
 421                                 "diag %s\n", dev_dir_name);
 422                         goto error_disable_channels;
 423                 }
 424                 if (!num_channels) {
 425                         fprintf(stderr, "Still no channels after "
 426                                 "auto-enabling, giving up\n");
 427                         goto error_disable_channels;
 428                 }
 429         }
 430
 431         if (!num_channels && autochannels == AUTOCHANNELS_DISABLED) {
 432                 fprintf(stderr,
 433                         "No channels are enabled, we have nothing to scan.\n");
 434                 fprintf(stderr, "Enable channels manually in "
 435                         FORMAT_SCAN_ELEMENTS_DIR
 436                         "/*_en or pass -a to autoenable channels and "
 437                         "try again.\n", dev_dir_name);
 438                 ret = -ENOENT;
 439                 goto error_free_triggername;
 440         }
 441
 442         /*
 443          * Construct the directory name for the associated buffer.
 444          * As we know that the lis3l02dq has only one buffer this may
 445          * be built rather than found.
 446          */
 447         ret = asprintf(&buf_dir_name,
 448                        "%siio:device%d/buffer", iio_dir, dev_num);
 449         if (ret < 0) {
 450                 ret = -ENOMEM;
 451                 goto error_free_channels;
 452         }
 453
 454         if (!notrigger) {
 455                 printf("%s %s\n", dev_dir_name, trigger_name);
 456                 /*
 457                  * Set the device trigger to be the data ready trigger found
 458                  * above
 459                  */
 460                 ret = write_sysfs_string_and_verify("trigger/current_trigger",
 461                                                     dev_dir_name,
 462                                                     trigger_name);
 463                 if (ret < 0) {
 464                         fprintf(stderr,
 465                                 "Failed to write current_trigger file\n");
 466                         goto error_free_buf_dir_name;
 467                 }
 468         }
 469
 470         /* Setup ring buffer parameters */
 471         ret = write_sysfs_int("length", buf_dir_name, buf_len);
 472         if (ret < 0)
 473                 goto error_free_buf_dir_name;
 474
 475         /* Enable the buffer */
 476         ret = write_sysfs_int("enable", buf_dir_name, 1);
 477         if (ret < 0) {
 478                 fprintf(stderr,
 479                         "Failed to enable buffer: %s\n", strerror(-ret));
 480                 goto error_free_buf_dir_name;
 481         }
 482
 483         scan_size = size_from_channelarray(channels, num_channels);
 484         data = malloc(scan_size * buf_len);
 485         if (!data) {
 486                 ret = -ENOMEM;
 487                 goto error_free_buf_dir_name;
 488         }
 489
 490         ret = asprintf(&buffer_access, "/dev/iio:device%d", dev_num);
 491         if (ret < 0) {
 492                 ret = -ENOMEM;
 493                 goto error_free_data;
 494         }
 495
 496         /* Attempt to open non blocking the access dev */
 497         fp = open(buffer_access, O_RDONLY | O_NONBLOCK);
 498         if (fp == -1) { /* TODO: If it isn't there make the node */
 499                 ret = -errno;
 500                 fprintf(stderr, "Failed to open %s\n", buffer_access);
 501                 goto error_free_buffer_access;
 502         }
 503
 504         for (j = 0; j < num_loops; j++) {
 505                 if (!noevents) {
 506                         struct pollfd pfd = {
 507                                 .fd = fp,
 508                                 .events = POLLIN,
 509                         };
 510
 511                         ret = poll(&pfd, 1, -1);
 512                         if (ret < 0) {
 513                                 ret = -errno;
 514                                 goto error_close_buffer_access;
 515                         } else if (ret == 0) {
 516                                 continue;
 517                         }
 518
 519                         toread = buf_len;
 520                 } else {
 521                         usleep(timedelay);
 522                         toread = 64;
 523                 }
 524
 525                 read_size = read(fp, data, toread * scan_size);
 526                 if (read_size < 0) {
 527                         if (errno == EAGAIN) {
 528                                 fprintf(stderr, "nothing available\n");
 529                                 continue;
 530                         } else {
 531                                 break;
 532                         }
 533                 }
 534                 for (i = 0; i < read_size / scan_size; i++)
 535                         process_scan(data + scan_size * i, channels,
 536                                      num_channels);
 537         }
 538
 539         /* Stop the buffer */
 540         ret = write_sysfs_int("enable", buf_dir_name, 0);
 541         if (ret < 0)
 542                 goto error_close_buffer_access;
 543
 544         if (!notrigger)
 545                 /* Disconnect the trigger - just write a dummy name. */
 546                 ret = write_sysfs_string("trigger/current_trigger",
 547                                          dev_dir_name, "NULL");
 548                 if (ret < 0)
 549                         fprintf(stderr, "Failed to write to %s\n",
 550                                 dev_dir_name);
 551
 552 error_close_buffer_access:
 553         if (close(fp) == -1)
 554                 perror("Failed to close buffer");
 555
 556 error_free_buffer_access:
 557         free(buffer_access);
 558 error_free_data:
 559         free(data);
 560 error_free_buf_dir_name:
 561         free(buf_dir_name);
 562 error_free_channels:
 563         for (i = num_channels - 1; i >= 0; i--) {
 564                 free(channels[i].name);
 565                 free(channels[i].generic_name);
 566         }
 567         free(channels);
 568 error_free_triggername:
 569         if (datardytrigger)
 570                 free(trigger_name);
 571 error_disable_channels:
 572         if (autochannels == AUTOCHANNELS_ACTIVE) {
 573                 ret = enable_disable_all_channels(dev_dir_name, 0);
 574                 if (ret)
 575                         fprintf(stderr, "Failed to disable all channels\n");
 576         }
 577 error_free_dev_dir_name:
 578         free(dev_dir_name);
 579
 580         return ret;
 581 }