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  * size_from_channelarray() - calculate the storage size of a scan
  39  * @channels:           the channel info array
  40  * @num_channels:       number of channels
  41  *
  42  * Has the side effect of filling the channels[i].location values used
  43  * in processing the buffer output.
  44  **/
  45 int size_from_channelarray(struct iio_channel_info *channels, int num_channels)
  46 {
  47         int bytes = 0;
  48         int i = 0;
  49
  50         while (i < num_channels) {
  51                 if (bytes % channels[i].bytes == 0)
  52                         channels[i].location = bytes;
  53                 else
  54                         channels[i].location = bytes - bytes % channels[i].bytes
  55                                                + channels[i].bytes;
  56
  57                 bytes = channels[i].location + channels[i].bytes;
  58                 i++;
  59         }
  60
  61         return bytes;
  62 }
  63
  64 void print1byte(uint8_t input, struct iio_channel_info *info)
  65 {
  66         /*
  67          * Shift before conversion to avoid sign extension
  68          * of left aligned data
  69          */
  70         input >>= info->shift;
  71         input &= info->mask;
  72         if (info->is_signed) {
  73                 int8_t val = (int8_t)(input << (8 - info->bits_used)) >>
  74                              (8 - info->bits_used);
  75                 printf("%05f ", ((float)val + info->offset) * info->scale);
  76         } else {
  77                 printf("%05f ", ((float)input + info->offset) * info->scale);
  78         }
  79 }
  80
  81 void print2byte(uint16_t input, struct iio_channel_info *info)
  82 {
  83         /* First swap if incorrect endian */
  84         if (info->be)
  85                 input = be16toh(input);
  86         else
  87                 input = le16toh(input);
  88
  89         /*
  90          * Shift before conversion to avoid sign extension
  91          * of left aligned data
  92          */
  93         input >>= info->shift;
  94         input &= info->mask;
  95         if (info->is_signed) {
  96                 int16_t val = (int16_t)(input << (16 - info->bits_used)) >>
  97                               (16 - info->bits_used);
  98                 printf("%05f ", ((float)val + info->offset) * info->scale);
  99         } else {
 100                 printf("%05f ", ((float)input + info->offset) * info->scale);
 101         }
 102 }
 103
 104 void print4byte(uint32_t input, struct iio_channel_info *info)
 105 {
 106         /* First swap if incorrect endian */
 107         if (info->be)
 108                 input = be32toh(input);
 109         else
 110                 input = le32toh(input);
 111
 112         /*
 113          * Shift before conversion to avoid sign extension
 114          * of left aligned data
 115          */
 116         input >>= info->shift;
 117         input &= info->mask;
 118         if (info->is_signed) {
 119                 int32_t val = (int32_t)(input << (32 - info->bits_used)) >>
 120                               (32 - info->bits_used);
 121                 printf("%05f ", ((float)val + info->offset) * info->scale);
 122         } else {
 123                 printf("%05f ", ((float)input + info->offset) * info->scale);
 124         }
 125 }
 126
 127 void print8byte(uint64_t input, struct iio_channel_info *info)
 128 {
 129         /* First swap if incorrect endian */
 130         if (info->be)
 131                 input = be64toh(input);
 132         else
 133                 input = le64toh(input);
 134
 135         /*
 136          * Shift before conversion to avoid sign extension
 137          * of left aligned data
 138          */
 139         input >>= info->shift;
 140         input &= info->mask;
 141         if (info->is_signed) {
 142                 int64_t val = (int64_t)(input << (64 - info->bits_used)) >>
 143                               (64 - info->bits_used);
 144                 /* special case for timestamp */
 145                 if (info->scale == 1.0f && info->offset == 0.0f)
 146                         printf("%" PRId64 " ", val);
 147                 else
 148                         printf("%05f ",
 149                                ((float)val + info->offset) * info->scale);
 150         } else {
 151                 printf("%05f ", ((float)input + info->offset) * info->scale);
 152         }
 153 }
 154
 155 /**
 156  * process_scan() - print out the values in SI units
 157  * @data:               pointer to the start of the scan
 158  * @channels:           information about the channels.
 159  *                      Note: size_from_channelarray must have been called first
 160  *                            to fill the location offsets.
 161  * @num_channels:       number of channels
 162  **/
 163 void process_scan(char *data,
 164                   struct iio_channel_info *channels,
 165                   int num_channels)
 166 {
 167         int k;
 168
 169         for (k = 0; k < num_channels; k++)
 170                 switch (channels[k].bytes) {
 171                         /* only a few cases implemented so far */
 172                 case 1:
 173                         print1byte(*(uint8_t *)(data + channels[k].location),
 174                                    &channels[k]);
 175                         break;
 176                 case 2:
 177                         print2byte(*(uint16_t *)(data + channels[k].location),
 178                                    &channels[k]);
 179                         break;
 180                 case 4:
 181                         print4byte(*(uint32_t *)(data + channels[k].location),
 182                                    &channels[k]);
 183                         break;
 184                 case 8:
 185                         print8byte(*(uint64_t *)(data + channels[k].location),
 186                                    &channels[k]);
 187                         break;
 188                 default:
 189                         break;
 190                 }
 191         printf("\n");
 192 }
 193
 194 void print_usage(void)
 195 {
 196         fprintf(stderr, "Usage: generic_buffer [options]...\n"
 197                 "Capture, convert and output data from IIO device buffer\n"
 198                 "  -c <n>     Do n conversions\n"
 199                 "  -e         Disable wait for event (new data)\n"
 200                 "  -g         Use trigger-less mode\n"
 201                 "  -l <n>     Set buffer length to n samples\n"
 202                 "  -n <name>  Set device name (mandatory)\n"
 203                 "  -t <name>  Set trigger name\n"
 204                 "  -w <n>     Set delay between reads in us (event-less mode)\n");
 205 }
 206
 207 int main(int argc, char **argv)
 208 {
 209         unsigned long num_loops = 2;
 210         unsigned long timedelay = 1000000;
 211         unsigned long buf_len = 128;
 212
 213         int ret, c, i, j, toread;
 214         int fp;
 215
 216         int num_channels;
 217         char *trigger_name = NULL, *device_name = NULL;
 218         char *dev_dir_name, *buf_dir_name;
 219
 220         int datardytrigger = 1;
 221         char *data;
 222         ssize_t read_size;
 223         int dev_num, trig_num;
 224         char *buffer_access;
 225         int scan_size;
 226         int noevents = 0;
 227         int notrigger = 0;
 228         char *dummy;
 229
 230         struct iio_channel_info *channels;
 231
 232         while ((c = getopt(argc, argv, "c:egl:n:t:w:")) != -1) {
 233                 switch (c) {
 234                 case 'c':
 235                         errno = 0;
 236                         num_loops = strtoul(optarg, &dummy, 10);
 237                         if (errno)
 238                                 return -errno;
 239
 240                         break;
 241                 case 'e':
 242                         noevents = 1;
 243                         break;
 244                 case 'g':
 245                         notrigger = 1;
 246                         break;
 247                 case 'l':
 248                         errno = 0;
 249                         buf_len = strtoul(optarg, &dummy, 10);
 250                         if (errno)
 251                                 return -errno;
 252
 253                         break;
 254                 case 'n':
 255                         device_name = optarg;
 256                         break;
 257                 case 't':
 258                         trigger_name = optarg;
 259                         datardytrigger = 0;
 260                         break;
 261                 case 'w':
 262                         errno = 0;
 263                         timedelay = strtoul(optarg, &dummy, 10);
 264                         if (errno)
 265                                 return -errno;
 266                         break;
 267                 case '?':
 268                         print_usage();
 269                         return -1;
 270                 }
 271         }
 272
 273         if (!device_name) {
 274                 fprintf(stderr, "Device name not set\n");
 275                 print_usage();
 276                 return -1;
 277         }
 278
 279         /* Find the device requested */
 280         dev_num = find_type_by_name(device_name, "iio:device");
 281         if (dev_num < 0) {
 282                 fprintf(stderr, "Failed to find the %s\n", device_name);
 283                 return dev_num;
 284         }
 285
 286         printf("iio device number being used is %d\n", dev_num);
 287
 288         ret = asprintf(&dev_dir_name, "%siio:device%d", iio_dir, dev_num);
 289         if (ret < 0)
 290                 return -ENOMEM;
 291
 292         if (!notrigger) {
 293                 if (!trigger_name) {
 294                         /*
 295                          * Build the trigger name. If it is device associated
 296                          * its name is <device_name>_dev[n] where n matches
 297                          * the device number found above.
 298                          */
 299                         ret = asprintf(&trigger_name,
 300                                        "%s-dev%d", device_name, dev_num);
 301                         if (ret < 0) {
 302                                 ret = -ENOMEM;
 303                                 goto error_free_dev_dir_name;
 304                         }
 305                 }
 306
 307                 /* Verify the trigger exists */
 308                 trig_num = find_type_by_name(trigger_name, "trigger");
 309                 if (trig_num < 0) {
 310                         fprintf(stderr, "Failed to find the trigger %s\n",
 311                                 trigger_name);
 312                         ret = trig_num;
 313                         goto error_free_triggername;
 314                 }
 315
 316                 printf("iio trigger number being used is %d\n", trig_num);
 317         } else {
 318                 printf("trigger-less mode selected\n");
 319         }
 320
 321         /*
 322          * Parse the files in scan_elements to identify what channels are
 323          * present
 324          */
 325         ret = build_channel_array(dev_dir_name, &channels, &num_channels);
 326         if (ret) {
 327                 fprintf(stderr, "Problem reading scan element information\n"
 328                         "diag %s\n", dev_dir_name);
 329                 goto error_free_triggername;
 330         }
 331         if (!num_channels) {
 332                 fprintf(stderr,
 333                         "No channels are enabled, we have nothing to scan.\n");
 334                 fprintf(stderr, "Enable channels manually in "
 335                         FORMAT_SCAN_ELEMENTS_DIR
 336                         "/*_en and try again.\n", dev_dir_name);
 337                 ret = -ENOENT;
 338                 goto error_free_triggername;
 339         }
 340
 341         /*
 342          * Construct the directory name for the associated buffer.
 343          * As we know that the lis3l02dq has only one buffer this may
 344          * be built rather than found.
 345          */
 346         ret = asprintf(&buf_dir_name,
 347                        "%siio:device%d/buffer", iio_dir, dev_num);
 348         if (ret < 0) {
 349                 ret = -ENOMEM;
 350                 goto error_free_channels;
 351         }
 352
 353         if (!notrigger) {
 354                 printf("%s %s\n", dev_dir_name, trigger_name);
 355                 /*
 356                  * Set the device trigger to be the data ready trigger found
 357                  * above
 358                  */
 359                 ret = write_sysfs_string_and_verify("trigger/current_trigger",
 360                                                     dev_dir_name,
 361                                                     trigger_name);
 362                 if (ret < 0) {
 363                         fprintf(stderr,
 364                                 "Failed to write current_trigger file\n");
 365                         goto error_free_buf_dir_name;
 366                 }
 367         }
 368
 369         /* Setup ring buffer parameters */
 370         ret = write_sysfs_int("length", buf_dir_name, buf_len);
 371         if (ret < 0)
 372                 goto error_free_buf_dir_name;
 373
 374         /* Enable the buffer */
 375         ret = write_sysfs_int("enable", buf_dir_name, 1);
 376         if (ret < 0) {
 377                 fprintf(stderr,
 378                         "Failed to enable buffer: %s\n", strerror(-ret));
 379                 goto error_free_buf_dir_name;
 380         }
 381
 382         scan_size = size_from_channelarray(channels, num_channels);
 383         data = malloc(scan_size * buf_len);
 384         if (!data) {
 385                 ret = -ENOMEM;
 386                 goto error_free_buf_dir_name;
 387         }
 388
 389         ret = asprintf(&buffer_access, "/dev/iio:device%d", dev_num);
 390         if (ret < 0) {
 391                 ret = -ENOMEM;
 392                 goto error_free_data;
 393         }
 394
 395         /* Attempt to open non blocking the access dev */
 396         fp = open(buffer_access, O_RDONLY | O_NONBLOCK);
 397         if (fp == -1) { /* TODO: If it isn't there make the node */
 398                 ret = -errno;
 399                 fprintf(stderr, "Failed to open %s\n", buffer_access);
 400                 goto error_free_buffer_access;
 401         }
 402
 403         for (j = 0; j < num_loops; j++) {
 404                 if (!noevents) {
 405                         struct pollfd pfd = {
 406                                 .fd = fp,
 407                                 .events = POLLIN,
 408                         };
 409
 410                         ret = poll(&pfd, 1, -1);
 411                         if (ret < 0) {
 412                                 ret = -errno;
 413                                 goto error_close_buffer_access;
 414                         } else if (ret == 0) {
 415                                 continue;
 416                         }
 417
 418                         toread = buf_len;
 419                 } else {
 420                         usleep(timedelay);
 421                         toread = 64;
 422                 }
 423
 424                 read_size = read(fp, data, toread * scan_size);
 425                 if (read_size < 0) {
 426                         if (errno == EAGAIN) {
 427                                 fprintf(stderr, "nothing available\n");
 428                                 continue;
 429                         } else {
 430                                 break;
 431                         }
 432                 }
 433                 for (i = 0; i < read_size / scan_size; i++)
 434                         process_scan(data + scan_size * i, channels,
 435                                      num_channels);
 436         }
 437
 438         /* Stop the buffer */
 439         ret = write_sysfs_int("enable", buf_dir_name, 0);
 440         if (ret < 0)
 441                 goto error_close_buffer_access;
 442
 443         if (!notrigger)
 444                 /* Disconnect the trigger - just write a dummy name. */
 445                 ret = write_sysfs_string("trigger/current_trigger",
 446                                          dev_dir_name, "NULL");
 447                 if (ret < 0)
 448                         fprintf(stderr, "Failed to write to %s\n",
 449                                 dev_dir_name);
 450
 451 error_close_buffer_access:
 452         if (close(fp) == -1)
 453                 perror("Failed to close buffer");
 454
 455 error_free_buffer_access:
 456         free(buffer_access);
 457 error_free_data:
 458         free(data);
 459 error_free_buf_dir_name:
 460         free(buf_dir_name);
 461 error_free_channels:
 462         for (i = num_channels - 1; i >= 0; i--) {
 463                 free(channels[i].name);
 464                 free(channels[i].generic_name);
 465         }
 466         free(channels);
 467 error_free_triggername:
 468         if (datardytrigger)
 469                 free(trigger_name);
 470
 471 error_free_dev_dir_name:
 472         free(dev_dir_name);
 473
 474         return ret;
 475 }