1 // SPDX-License-Identifier: GPL-2.0-only 2 /* Industrialio buffer test code. 3 * 4 * Copyright (c) 2008 Jonathan Cameron 5 * 6 * This program is primarily intended as an example application. 7 * Reads the current buffer setup from sysfs and starts a short capture 8 * from the specified device, pretty printing the result after appropriate 9 * conversion. 10 * 11 * Command line parameters 12 * generic_buffer -n <device_name> -t <trigger_name> 13 * If trigger name is not specified the program assumes you want a dataready 14 * trigger associated with the device and goes looking for it. 15 */ 16 17 #include <unistd.h> 18 #include <stdlib.h> 19 #include <dirent.h> 20 #include <fcntl.h> 21 #include <stdio.h> 22 #include <errno.h> 23 #include <sys/stat.h> 24 #include <sys/dir.h> 25 #include <linux/types.h> 26 #include <string.h> 27 #include <poll.h> 28 #include <endian.h> 29 #include <getopt.h> 30 #include <inttypes.h> 31 #include <stdbool.h> 32 #include <signal.h> 33 #include <sys/ioctl.h> 34 #include <linux/iio/buffer.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 static 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 static 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 static 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 static 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 static 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 static void process_scan(char *data, struct iio_channel_info *channels, 173 int num_channels) 174 { 175 int k; 176 177 for (k = 0; k < num_channels; k++) 178 switch (channels[k].bytes) { 179 /* only a few cases implemented so far */ 180 case 1: 181 print1byte(*(uint8_t *)(data + channels[k].location), 182 &channels[k]); 183 break; 184 case 2: 185 print2byte(*(uint16_t *)(data + channels[k].location), 186 &channels[k]); 187 break; 188 case 4: 189 print4byte(*(uint32_t *)(data + channels[k].location), 190 &channels[k]); 191 break; 192 case 8: 193 print8byte(*(uint64_t *)(data + channels[k].location), 194 &channels[k]); 195 break; 196 default: 197 break; 198 } 199 printf("\n"); 200 } 201 202 static int enable_disable_all_channels(char *dev_dir_name, int buffer_idx, int enable) 203 { 204 const struct dirent *ent; 205 char scanelemdir[256]; 206 DIR *dp; 207 int ret; 208 209 snprintf(scanelemdir, sizeof(scanelemdir), 210 FORMAT_SCAN_ELEMENTS_DIR, dev_dir_name, buffer_idx); 211 scanelemdir[sizeof(scanelemdir)-1] = '\0'; 212 213 dp = opendir(scanelemdir); 214 if (!dp) { 215 fprintf(stderr, "Enabling/disabling channels: can't open %s\n", 216 scanelemdir); 217 return -EIO; 218 } 219 220 ret = -ENOENT; 221 while (ent = readdir(dp), ent) { 222 if (iioutils_check_suffix(ent->d_name, "_en")) { 223 printf("%sabling: %s\n", 224 enable ? "En" : "Dis", 225 ent->d_name); 226 ret = write_sysfs_int(ent->d_name, scanelemdir, 227 enable); 228 if (ret < 0) 229 fprintf(stderr, "Failed to enable/disable %s\n", 230 ent->d_name); 231 } 232 } 233 234 if (closedir(dp) == -1) { 235 perror("Enabling/disabling channels: " 236 "Failed to close directory"); 237 return -errno; 238 } 239 return 0; 240 } 241 242 static void print_usage(void) 243 { 244 fprintf(stderr, "Usage: generic_buffer [options]...\n" 245 "Capture, convert and output data from IIO device buffer\n" 246 " -a Auto-activate all available channels\n" 247 " -A Force-activate ALL channels\n" 248 " -b <n> The buffer which to open (by index), default 0\n" 249 " -c <n> Do n conversions, or loop forever if n < 0\n" 250 " -e Disable wait for event (new data)\n" 251 " -g Use trigger-less mode\n" 252 " -l <n> Set buffer length to n samples\n" 253 " --device-name -n <name>\n" 254 " --device-num -N <num>\n" 255 " Set device by name or number (mandatory)\n" 256 " --trigger-name -t <name>\n" 257 " --trigger-num -T <num>\n" 258 " Set trigger by name or number\n" 259 " -w <n> Set delay between reads in us (event-less mode)\n"); 260 } 261 262 static enum autochan autochannels = AUTOCHANNELS_DISABLED; 263 static char *dev_dir_name = NULL; 264 static char *buf_dir_name = NULL; 265 static int buffer_idx = 0; 266 static bool current_trigger_set = false; 267 268 static void cleanup(void) 269 { 270 int ret; 271 272 /* Disable trigger */ 273 if (dev_dir_name && current_trigger_set) { 274 /* Disconnect the trigger - just write a dummy name. */ 275 ret = write_sysfs_string("trigger/current_trigger", 276 dev_dir_name, "NULL"); 277 if (ret < 0) 278 fprintf(stderr, "Failed to disable trigger: %s\n", 279 strerror(-ret)); 280 current_trigger_set = false; 281 } 282 283 /* Disable buffer */ 284 if (buf_dir_name) { 285 ret = write_sysfs_int("enable", buf_dir_name, 0); 286 if (ret < 0) 287 fprintf(stderr, "Failed to disable buffer: %s\n", 288 strerror(-ret)); 289 } 290 291 /* Disable channels if auto-enabled */ 292 if (dev_dir_name && autochannels == AUTOCHANNELS_ACTIVE) { 293 ret = enable_disable_all_channels(dev_dir_name, buffer_idx, 0); 294 if (ret) 295 fprintf(stderr, "Failed to disable all channels\n"); 296 autochannels = AUTOCHANNELS_DISABLED; 297 } 298 } 299 300 static void sig_handler(int signum) 301 { 302 fprintf(stderr, "Caught signal %d\n", signum); 303 cleanup(); 304 exit(-signum); 305 } 306 307 static void register_cleanup(void) 308 { 309 struct sigaction sa = { .sa_handler = sig_handler }; 310 const int signums[] = { SIGINT, SIGTERM, SIGABRT }; 311 int ret, i; 312 313 for (i = 0; i < ARRAY_SIZE(signums); ++i) { 314 ret = sigaction(signums[i], &sa, NULL); 315 if (ret) { 316 perror("Failed to register signal handler"); 317 exit(-1); 318 } 319 } 320 } 321 322 static const struct option longopts[] = { 323 { "device-name", 1, 0, 'n' }, 324 { "device-num", 1, 0, 'N' }, 325 { "trigger-name", 1, 0, 't' }, 326 { "trigger-num", 1, 0, 'T' }, 327 { }, 328 }; 329 330 int main(int argc, char **argv) 331 { 332 long long num_loops = 2; 333 unsigned long timedelay = 1000000; 334 unsigned long buf_len = 128; 335 336 ssize_t i; 337 unsigned long long j; 338 unsigned long toread; 339 int ret, c; 340 struct stat st; 341 int fd = -1; 342 int buf_fd = -1; 343 344 int num_channels = 0; 345 char *trigger_name = NULL, *device_name = NULL; 346 347 char *data = NULL; 348 ssize_t read_size; 349 int dev_num = -1, trig_num = -1; 350 char *buffer_access = NULL; 351 int scan_size; 352 int noevents = 0; 353 int notrigger = 0; 354 char *dummy; 355 bool force_autochannels = false; 356 357 struct iio_channel_info *channels = NULL; 358 359 register_cleanup(); 360 361 while ((c = getopt_long(argc, argv, "aAb:c:egl:n:N:t:T:w:?", longopts, 362 NULL)) != -1) { 363 switch (c) { 364 case 'a': 365 autochannels = AUTOCHANNELS_ENABLED; 366 break; 367 case 'A': 368 autochannels = AUTOCHANNELS_ENABLED; 369 force_autochannels = true; 370 break; 371 case 'b': 372 errno = 0; 373 buffer_idx = strtoll(optarg, &dummy, 10); 374 if (errno) { 375 ret = -errno; 376 goto error; 377 } 378 if (buffer_idx < 0) { 379 ret = -ERANGE; 380 goto error; 381 } 382 383 break; 384 case 'c': 385 errno = 0; 386 num_loops = strtoll(optarg, &dummy, 10); 387 if (errno) { 388 ret = -errno; 389 goto error; 390 } 391 392 break; 393 case 'e': 394 noevents = 1; 395 break; 396 case 'g': 397 notrigger = 1; 398 break; 399 case 'l': 400 errno = 0; 401 buf_len = strtoul(optarg, &dummy, 10); 402 if (errno) { 403 ret = -errno; 404 goto error; 405 } 406 407 break; 408 case 'n': 409 device_name = strdup(optarg); 410 break; 411 case 'N': 412 errno = 0; 413 dev_num = strtoul(optarg, &dummy, 10); 414 if (errno) { 415 ret = -errno; 416 goto error; 417 } 418 break; 419 case 't': 420 trigger_name = strdup(optarg); 421 break; 422 case 'T': 423 errno = 0; 424 trig_num = strtoul(optarg, &dummy, 10); 425 if (errno) 426 return -errno; 427 break; 428 case 'w': 429 errno = 0; 430 timedelay = strtoul(optarg, &dummy, 10); 431 if (errno) { 432 ret = -errno; 433 goto error; 434 } 435 break; 436 case '?': 437 print_usage(); 438 ret = -1; 439 goto error; 440 } 441 } 442 443 /* Find the device requested */ 444 if (dev_num < 0 && !device_name) { 445 fprintf(stderr, "Device not set\n"); 446 print_usage(); 447 ret = -1; 448 goto error; 449 } else if (dev_num >= 0 && device_name) { 450 fprintf(stderr, "Only one of --device-num or --device-name needs to be set\n"); 451 print_usage(); 452 ret = -1; 453 goto error; 454 } else if (dev_num < 0) { 455 dev_num = find_type_by_name(device_name, "iio:device"); 456 if (dev_num < 0) { 457 fprintf(stderr, "Failed to find the %s\n", device_name); 458 ret = dev_num; 459 goto error; 460 } 461 } 462 printf("iio device number being used is %d\n", dev_num); 463 464 ret = asprintf(&dev_dir_name, "%siio:device%d", iio_dir, dev_num); 465 if (ret < 0) 466 return -ENOMEM; 467 /* Fetch device_name if specified by number */ 468 if (!device_name) { 469 device_name = malloc(IIO_MAX_NAME_LENGTH); 470 if (!device_name) { 471 ret = -ENOMEM; 472 goto error; 473 } 474 ret = read_sysfs_string("name", dev_dir_name, device_name); 475 if (ret < 0) { 476 fprintf(stderr, "Failed to read name of device %d\n", dev_num); 477 goto error; 478 } 479 } 480 481 if (notrigger) { 482 printf("trigger-less mode selected\n"); 483 } else if (trig_num >= 0) { 484 char *trig_dev_name; 485 ret = asprintf(&trig_dev_name, "%strigger%d", iio_dir, trig_num); 486 if (ret < 0) { 487 return -ENOMEM; 488 } 489 trigger_name = malloc(IIO_MAX_NAME_LENGTH); 490 ret = read_sysfs_string("name", trig_dev_name, trigger_name); 491 free(trig_dev_name); 492 if (ret < 0) { 493 fprintf(stderr, "Failed to read trigger%d name from\n", trig_num); 494 return ret; 495 } 496 printf("iio trigger number being used is %d\n", trig_num); 497 } else { 498 if (!trigger_name) { 499 /* 500 * Build the trigger name. If it is device associated 501 * its name is <device_name>_dev[n] where n matches 502 * the device number found above. 503 */ 504 ret = asprintf(&trigger_name, 505 "%s-dev%d", device_name, dev_num); 506 if (ret < 0) { 507 ret = -ENOMEM; 508 goto error; 509 } 510 } 511 512 /* Look for this "-devN" trigger */ 513 trig_num = find_type_by_name(trigger_name, "trigger"); 514 if (trig_num < 0) { 515 /* OK try the simpler "-trigger" suffix instead */ 516 free(trigger_name); 517 ret = asprintf(&trigger_name, 518 "%s-trigger", device_name); 519 if (ret < 0) { 520 ret = -ENOMEM; 521 goto error; 522 } 523 } 524 525 trig_num = find_type_by_name(trigger_name, "trigger"); 526 if (trig_num < 0) { 527 fprintf(stderr, "Failed to find the trigger %s\n", 528 trigger_name); 529 ret = trig_num; 530 goto error; 531 } 532 533 printf("iio trigger number being used is %d\n", trig_num); 534 } 535 536 /* 537 * Parse the files in scan_elements to identify what channels are 538 * present 539 */ 540 ret = build_channel_array(dev_dir_name, buffer_idx, &channels, &num_channels); 541 if (ret) { 542 fprintf(stderr, "Problem reading scan element information\n" 543 "diag %s\n", dev_dir_name); 544 goto error; 545 } 546 if (num_channels && autochannels == AUTOCHANNELS_ENABLED && 547 !force_autochannels) { 548 fprintf(stderr, "Auto-channels selected but some channels " 549 "are already activated in sysfs\n"); 550 fprintf(stderr, "Proceeding without activating any channels\n"); 551 } 552 553 if ((!num_channels && autochannels == AUTOCHANNELS_ENABLED) || 554 (autochannels == AUTOCHANNELS_ENABLED && force_autochannels)) { 555 fprintf(stderr, "Enabling all channels\n"); 556 557 ret = enable_disable_all_channels(dev_dir_name, buffer_idx, 1); 558 if (ret) { 559 fprintf(stderr, "Failed to enable all channels\n"); 560 goto error; 561 } 562 563 /* This flags that we need to disable the channels again */ 564 autochannels = AUTOCHANNELS_ACTIVE; 565 566 ret = build_channel_array(dev_dir_name, buffer_idx, &channels, 567 &num_channels); 568 if (ret) { 569 fprintf(stderr, "Problem reading scan element " 570 "information\n" 571 "diag %s\n", dev_dir_name); 572 goto error; 573 } 574 if (!num_channels) { 575 fprintf(stderr, "Still no channels after " 576 "auto-enabling, giving up\n"); 577 goto error; 578 } 579 } 580 581 if (!num_channels && autochannels == AUTOCHANNELS_DISABLED) { 582 fprintf(stderr, 583 "No channels are enabled, we have nothing to scan.\n"); 584 fprintf(stderr, "Enable channels manually in " 585 FORMAT_SCAN_ELEMENTS_DIR 586 "/*_en or pass -a to autoenable channels and " 587 "try again.\n", dev_dir_name, buffer_idx); 588 ret = -ENOENT; 589 goto error; 590 } 591 592 /* 593 * Construct the directory name for the associated buffer. 594 * As we know that the lis3l02dq has only one buffer this may 595 * be built rather than found. 596 */ 597 ret = asprintf(&buf_dir_name, 598 "%siio:device%d/buffer%d", iio_dir, dev_num, buffer_idx); 599 if (ret < 0) { 600 ret = -ENOMEM; 601 goto error; 602 } 603 604 if (stat(buf_dir_name, &st)) { 605 fprintf(stderr, "Could not stat() '%s', got error %d: %s\n", 606 buf_dir_name, errno, strerror(errno)); 607 ret = -errno; 608 goto error; 609 } 610 611 if (!S_ISDIR(st.st_mode)) { 612 fprintf(stderr, "File '%s' is not a directory\n", buf_dir_name); 613 ret = -EFAULT; 614 goto error; 615 } 616 617 if (!notrigger) { 618 printf("%s %s\n", dev_dir_name, trigger_name); 619 /* 620 * Set the device trigger to be the data ready trigger found 621 * above 622 */ 623 ret = write_sysfs_string_and_verify("trigger/current_trigger", 624 dev_dir_name, 625 trigger_name); 626 if (ret < 0) { 627 fprintf(stderr, 628 "Failed to write current_trigger file\n"); 629 goto error; 630 } 631 } 632 633 ret = asprintf(&buffer_access, "/dev/iio:device%d", dev_num); 634 if (ret < 0) { 635 ret = -ENOMEM; 636 goto error; 637 } 638 639 /* Attempt to open non blocking the access dev */ 640 fd = open(buffer_access, O_RDONLY | O_NONBLOCK); 641 if (fd == -1) { /* TODO: If it isn't there make the node */ 642 ret = -errno; 643 fprintf(stderr, "Failed to open %s\n", buffer_access); 644 goto error; 645 } 646 647 /* specify for which buffer index we want an FD */ 648 buf_fd = buffer_idx; 649 650 ret = ioctl(fd, IIO_BUFFER_GET_FD_IOCTL, &buf_fd); 651 if (ret == -1 || buf_fd == -1) { 652 ret = -errno; 653 if (ret == -ENODEV || ret == -EINVAL) 654 fprintf(stderr, 655 "Device does not have this many buffers\n"); 656 else 657 fprintf(stderr, "Failed to retrieve buffer fd\n"); 658 659 goto error; 660 } 661 662 /* Setup ring buffer parameters */ 663 ret = write_sysfs_int("length", buf_dir_name, buf_len); 664 if (ret < 0) 665 goto error; 666 667 /* Enable the buffer */ 668 ret = write_sysfs_int("enable", buf_dir_name, 1); 669 if (ret < 0) { 670 fprintf(stderr, 671 "Failed to enable buffer '%s': %s\n", 672 buf_dir_name, strerror(-ret)); 673 goto error; 674 } 675 676 scan_size = size_from_channelarray(channels, num_channels); 677 data = malloc(scan_size * buf_len); 678 if (!data) { 679 ret = -ENOMEM; 680 goto error; 681 } 682 683 /** 684 * This check is being done here for sanity reasons, however it 685 * should be omitted under normal operation. 686 * If this is buffer0, we check that we get EBUSY after this point. 687 */ 688 if (buffer_idx == 0) { 689 errno = 0; 690 read_size = read(fd, data, 1); 691 if (read_size > -1 || errno != EBUSY) { 692 ret = -EFAULT; 693 perror("Reading from '%s' should not be possible after ioctl()"); 694 goto error; 695 } 696 } 697 698 /* close now the main chardev FD and let the buffer FD work */ 699 if (close(fd) == -1) 700 perror("Failed to close character device file"); 701 fd = -1; 702 703 for (j = 0; j < num_loops || num_loops < 0; j++) { 704 if (!noevents) { 705 struct pollfd pfd = { 706 .fd = buf_fd, 707 .events = POLLIN, 708 }; 709 710 ret = poll(&pfd, 1, -1); 711 if (ret < 0) { 712 ret = -errno; 713 goto error; 714 } else if (ret == 0) { 715 continue; 716 } 717 718 } else { 719 usleep(timedelay); 720 } 721 722 toread = buf_len; 723 724 read_size = read(buf_fd, data, toread * scan_size); 725 if (read_size < 0) { 726 if (errno == EAGAIN) { 727 fprintf(stderr, "nothing available\n"); 728 continue; 729 } else { 730 break; 731 } 732 } 733 for (i = 0; i < read_size / scan_size; i++) 734 process_scan(data + scan_size * i, channels, 735 num_channels); 736 } 737 738 error: 739 cleanup(); 740 741 if (fd >= 0 && close(fd) == -1) 742 perror("Failed to close character device"); 743 if (buf_fd >= 0 && close(buf_fd) == -1) 744 perror("Failed to close buffer"); 745 free(buffer_access); 746 free(data); 747 free(buf_dir_name); 748 for (i = num_channels - 1; i >= 0; i--) { 749 free(channels[i].name); 750 free(channels[i].generic_name); 751 } 752 free(channels); 753 free(trigger_name); 754 free(device_name); 755 free(dev_dir_name); 756 757 return ret; 758 } 759