control.c

   1 /*
   2  * Copyright (C) 2014 Intel Corporation.
   3  */
   4
   5 #include <stdlib.h>
   6 #include <ctype.h>
   7 #include <fcntl.h>
   8 #include <sys/epoll.h>
   9 #include <sys/socket.h>
  10 #include <utils/Log.h>
  11 #include <hardware/sensors.h>
  12 #include "control.h"
  13 #include "enumeration.h"
  14 #include "utils.h"
  15 #include "transform.h"
  16 #include "calibration.h"
  17
  18 /* Currently active sensors count, per device */
  19 static int poll_sensors_per_dev[MAX_DEVICES];   /* poll-mode sensors */
  20 static int trig_sensors_per_dev[MAX_DEVICES];   /* trigger, event based */
  21
  22 static int device_fd[MAX_DEVICES];   /* fd on the /dev/iio:deviceX file */
  23
  24 static int poll_fd; /* epoll instance covering all enabled sensors */
  25
  26 static int poll_socket_pair[2]; /* used to unblock the poll loop */
  27
  28 /* Timestamp for the moment when we last exited a poll operation */
  29 static int64_t last_poll_exit_ts;
  30
  31 static int active_poll_sensors; /* Number of enabled poll-mode sensors */
  32
  33 #define INVALID_DEV_NUM ((uint32_t) -1)
  34
  35
  36 static int enable_buffer(int dev_num, int enabled)
  37 {
  38         char sysfs_path[PATH_MAX];
  39
  40         sprintf(sysfs_path, ENABLE_PATH, dev_num);
  41
  42         /* Low level, non-multiplexed, enable/disable routine */
  43         return sysfs_write_int(sysfs_path, enabled);
  44 }
  45
  46
  47 static int setup_trigger(int dev_num, const char* trigger_val)
  48 {
  49         char sysfs_path[PATH_MAX];
  50
  51         sprintf(sysfs_path, TRIGGER_PATH, dev_num);
  52
  53         return sysfs_write_str(sysfs_path, trigger_val);
  54 }
  55
  56
  57 void build_sensor_report_maps(int dev_num)
  58 {
  59         /*
  60          * Read sysfs files from a iio device's scan_element directory, and
  61          * build a couple of tables from that data. These tables will tell, for
  62          * each sensor, where to gather relevant data in a device report, i.e.
  63          * the structure that we read from the /dev/iio:deviceX file in order to
  64          * sensor report, itself being the data that we return to Android when a
  65          * sensor poll completes. The mapping should be straightforward in the
  66          * case where we have a single sensor active per iio device but, this is
  67          * not the general case. In general several sensors can be handled
  68          * through a single iio device, and the _en, _index and _type syfs
  69          * entries all concur to paint a picture of what the structure of the
  70          * device report is.
  71          */
  72
  73         int s;
  74         int c;
  75         int n;
  76         int i;
  77         int ch_index;
  78         char* ch_spec;
  79         char spec_buf[MAX_TYPE_SPEC_LEN];
  80         struct datum_info_t* ch_info;
  81         int size;
  82         char sysfs_path[PATH_MAX];
  83         int known_channels;
  84         int offset;
  85         int channel_size_from_index[MAX_SENSORS * MAX_CHANNELS] = { 0 };
  86         int sensor_handle_from_index[MAX_SENSORS * MAX_CHANNELS] = { 0 };
  87         int channel_number_from_index[MAX_SENSORS * MAX_CHANNELS] = { 0 };
  88
  89         known_channels = 0;
  90
  91         /* For each sensor that is linked to this device */
  92         for (s=0; s<sensor_count; s++) {
  93                 if (sensor_info[s].dev_num != dev_num)
  94                         continue;
  95
  96                 i = sensor_info[s].catalog_index;
  97
  98                 /* Read channel details through sysfs attributes */
  99                 for (c=0; c<sensor_info[s].num_channels; c++) {
 100
 101                         /* Read _type file */
 102                         sprintf(sysfs_path, CHANNEL_PATH "%s",
 103                                 sensor_info[s].dev_num,
 104                                 sensor_catalog[i].channel[c].type_path);
 105
 106                         n = sysfs_read_str(sysfs_path, spec_buf,
 107                                                 sizeof(spec_buf));
 108
 109                         if (n == -1) {
 110                                         ALOGW(  "Failed to read type: %s\n",
 111                                         sysfs_path);
 112                                         continue;
 113                                 }
 114
 115                         ch_spec = sensor_info[s].channel[c].type_spec;
 116
 117                         memcpy(ch_spec, spec_buf, sizeof(spec_buf));
 118
 119                         ch_info = &sensor_info[s].channel[c].type_info;
 120
 121                         size = decode_type_spec(ch_spec, ch_info);
 122
 123                         /* Read _index file */
 124                         sprintf(sysfs_path, CHANNEL_PATH "%s",
 125                                 sensor_info[s].dev_num,
 126                                 sensor_catalog[i].channel[c].index_path);
 127
 128                         n = sysfs_read_int(sysfs_path, &ch_index);
 129
 130                         if (n == -1) {
 131                                         ALOGW(  "Failed to read index: %s\n",
 132                                                 sysfs_path);
 133                                         continue;
 134                                 }
 135
 136                         if (ch_index >= MAX_SENSORS) {
 137                                 ALOGE("Index out of bounds!: %s\n", sysfs_path);
 138                                 continue;
 139                         }
 140
 141                         /* Record what this index is about */
 142
 143                         sensor_handle_from_index [ch_index] = s;
 144                         channel_number_from_index[ch_index] = c;
 145                         channel_size_from_index  [ch_index] = size;
 146
 147                         known_channels++;
 148                 }
 149
 150                 /* Stop sampling - if we are recovering from hal restart */
 151                 enable_buffer(dev_num, 0);
 152                 setup_trigger(dev_num, "\n");
 153
 154                 /* Turn on channels we're aware of */
 155                 for (c=0;c<sensor_info[s].num_channels; c++) {
 156                         sprintf(sysfs_path, CHANNEL_PATH "%s",
 157                                 sensor_info[s].dev_num,
 158                                 sensor_catalog[i].channel[c].en_path);
 159                         sysfs_write_int(sysfs_path, 1);
 160                 }
 161         }
 162
 163         ALOGI("Found %d channels on iio device %d\n", known_channels, dev_num);
 164
 165         /*
 166          * Now that we know which channels are defined, their sizes and their
 167          * ordering, update channels offsets within device report. Note: there
 168          * is a possibility that several sensors share the same index, with
 169          * their data fields being isolated by masking and shifting as specified
 170          * through the real bits and shift values in type attributes. This case
 171          * is not currently supported. Also, the code below assumes no hole in
 172          * the sequence of indices, so it is dependent on discovery of all
 173          * sensors.
 174          */
 175          offset = 0;
 176          for (i=0; i<MAX_SENSORS * MAX_CHANNELS; i++) {
 177                 s =     sensor_handle_from_index[i];
 178                 c =     channel_number_from_index[i];
 179                 size =  channel_size_from_index[i];
 180
 181                 if (!size)
 182                         continue;
 183
 184                 ALOGI("S%d C%d : offset %d, size %d, type %s\n",
 185                       s, c, offset, size, sensor_info[s].channel[c].type_spec);
 186
 187                 sensor_info[s].channel[c].offset        = offset;
 188                 sensor_info[s].channel[c].size          = size;
 189
 190                 offset += size;
 191          }
 192 }
 193
 194
 195 int adjust_counters (int s, int enabled)
 196 {
 197         /*
 198          * Adjust counters based on sensor enable action. Return values are:
 199          * -1 if there's an inconsistency: abort action in this case
 200          *  0 if the operation was completed and we're all set
 201          *  1 if we toggled the state of the sensor and there's work left
 202          */
 203
 204         int dev_num = sensor_info[s].dev_num;
 205         int catalog_index = sensor_info[s].catalog_index;
 206         int sensor_type = sensor_catalog[catalog_index].type;
 207
 208         /* Refcount per sensor, in terms of enable count */
 209         if (enabled) {
 210                 ALOGI("Enabling sensor %d (iio device %d: %s)\n",
 211                         s, dev_num, sensor_info[s].friendly_name);
 212
 213                 sensor_info[s].enable_count++;
 214
 215                 if (sensor_info[s].enable_count != 1) {
 216                         return 0; /* The sensor was, and remains, in use */
 217                 } else {
 218                         if (sensor_type == SENSOR_TYPE_MAGNETIC_FIELD)
 219                                 compass_read_data(&sensor_info[s]);
 220
 221                         if (sensor_type == SENSOR_TYPE_GYROSCOPE)
 222                                 gyro_cal_init(&sensor_info[s]);
 223                 }
 224         } else {
 225                 if (sensor_info[s].enable_count == 0)
 226                         return -1; /* Spurious disable call */
 227
 228                 ALOGI("Disabling sensor %d (iio device %d: %s)\n", s, dev_num,
 229                       sensor_info[s].friendly_name);
 230
 231                 if (sensor_type == SENSOR_TYPE_MAGNETIC_FIELD)
 232                         compass_store_data(&sensor_info[s]);
 233
 234                 sensor_info[s].enable_count--;
 235
 236                 if (sensor_info[s].enable_count > 0)
 237                         return 0; /* The sensor was, and remains, in use */
 238
 239                 /* Sensor disabled, lower report available flag */
 240                 sensor_info[s].report_pending = 0;
 241         }
 242
 243         /* We changed the state of a sensor - adjust per iio device counters */
 244
 245         /* If this is a regular event-driven sensor */
 246         if (sensor_info[s].num_channels) {
 247
 248                         if (enabled)
 249                                 trig_sensors_per_dev[dev_num]++;
 250                         else
 251                                 trig_sensors_per_dev[dev_num]--;
 252
 253                         return 1;
 254                 }
 255
 256         if (enabled) {
 257                 active_poll_sensors++;
 258                 poll_sensors_per_dev[dev_num]++;
 259                 return 1;
 260         }
 261
 262         active_poll_sensors--;
 263         poll_sensors_per_dev[dev_num]--;
 264         return 1;
 265 }
 266
 267
 268 int sensor_activate(int s, int enabled)
 269 {
 270         char device_name[PATH_MAX];
 271         char trigger_name[MAX_NAME_SIZE + 16];
 272         int c;
 273         struct epoll_event ev = {0};
 274         int dev_fd;
 275         int ret;
 276         int dev_num = sensor_info[s].dev_num;
 277         int i = sensor_info[s].catalog_index;
 278         int is_poll_sensor = !sensor_info[s].num_channels;
 279
 280         ret = adjust_counters(s, enabled);
 281
 282         /* If the operation was neutral in terms of state, we're done */
 283         if (ret <= 0)
 284                 return ret;
 285
 286         if (!is_poll_sensor) {
 287
 288                 /* Stop sampling */
 289                 enable_buffer(dev_num, 0);
 290                 setup_trigger(dev_num, "\n");
 291
 292                 /* If there's at least one sensor enabled on this iio device */
 293                 if (trig_sensors_per_dev[dev_num]) {
 294                         sprintf(trigger_name, "%s-dev%d",
 295                                         sensor_info[s].internal_name, dev_num);
 296
 297                         /* Start sampling */
 298                         setup_trigger(dev_num, trigger_name);
 299                         enable_buffer(dev_num, 1);
 300                 }
 301         }
 302
 303         /*
 304          * Make sure we have a fd on the character device ; conversely, close
 305          * the fd if no one is using associated sensors anymore. The assumption
 306          * here is that the underlying driver will power on the relevant
 307          * hardware block while someone holds a fd on the device.
 308          */
 309         dev_fd = device_fd[dev_num];
 310
 311         if (!enabled) {
 312                 if (dev_fd != -1 && !poll_sensors_per_dev[dev_num] &&
 313                         !trig_sensors_per_dev[dev_num]) {
 314                                 /*
 315                                  * Stop watching this fd. This should be a no-op
 316                                  * in case this fd was not in the poll set.
 317                                  */
 318                                 epoll_ctl(poll_fd, EPOLL_CTL_DEL, dev_fd, NULL);
 319
 320                                 close(dev_fd);
 321                                 device_fd[dev_num] = -1;
 322                         }
 323                 return 0;
 324         }
 325
 326         if (dev_fd == -1) {
 327                 /* First enabled sensor on this iio device */
 328                 sprintf(device_name, DEV_FILE_PATH, dev_num);
 329                 dev_fd = open(device_name, O_RDONLY | O_NONBLOCK);
 330
 331                 device_fd[dev_num] = dev_fd;
 332
 333                 if (dev_fd == -1) {
 334                         ALOGE("Could not open fd on %s (%s)\n",
 335                               device_name, strerror(errno));
 336                         adjust_counters(s, 0);
 337                         return -1;
 338                 }
 339
 340                 ALOGV("Opened %s: fd=%d\n", device_name, dev_fd);
 341
 342                 if (!is_poll_sensor) {
 343
 344                         /* Add this iio device fd to the set of watched fds */
 345                         ev.events = EPOLLIN;
 346                         ev.data.u32 = dev_num;
 347
 348                         ret = epoll_ctl(poll_fd, EPOLL_CTL_ADD, dev_fd, &ev);
 349
 350                         if (ret == -1) {
 351                                 ALOGE(  "Failed adding %d to poll set (%s)\n",
 352                                         dev_fd, strerror(errno));
 353                                 return -1;
 354                         }
 355
 356                         /* Note: poll-mode fds are not readable */
 357                 }
 358         }
 359
 360         /* Release the polling loop so an updated timeout gets used */
 361         write(poll_socket_pair[1], "", 1);
 362
 363         return 0;
 364 }
 365
 366
 367 static int integrate_device_report(int dev_num)
 368 {
 369         int len;
 370         int s,c;
 371         unsigned char buf[MAX_SENSOR_REPORT_SIZE] = { 0 };
 372         int sr_offset;
 373         unsigned char *target;
 374         unsigned char *source;
 375         int size;
 376         int ts;
 377
 378         /* There's an incoming report on the specified fd */
 379
 380         if (dev_num < 0 || dev_num >= MAX_DEVICES) {
 381                 ALOGE("Event reported on unexpected iio device %d\n", dev_num);
 382                 return -1;
 383         }
 384
 385         if (device_fd[dev_num] == -1) {
 386                 ALOGE("Ignoring stale report on iio device %d\n", dev_num);
 387                 return -1;
 388         }
 389
 390         ts = get_timestamp();
 391
 392         len = read(device_fd[dev_num], buf, MAX_SENSOR_REPORT_SIZE);
 393
 394         if (len == -1) {
 395                 ALOGE("Could not read report from iio device %d (%s)\n",
 396                       dev_num, strerror(errno));
 397                 return -1;
 398         }
 399
 400         ALOGV("Read %d bytes from iio device %d\n", len, dev_num);
 401
 402         for (s=0; s<MAX_SENSORS; s++)
 403                 if (sensor_info[s].dev_num == dev_num &&
 404                     sensor_info[s].enable_count) {
 405
 406                         sr_offset = 0;
 407
 408                         /* Copy data from device to sensor report buffer */
 409                         for (c=0; c<sensor_info[s].num_channels; c++) {
 410
 411                                 target = sensor_info[s].report_buffer +
 412                                         sr_offset;
 413
 414                                 source = buf + sensor_info[s].channel[c].offset;
 415
 416                                 size = sensor_info[s].channel[c].size;
 417
 418                                 memcpy(target, source, size);
 419
 420                                 sr_offset += size;
 421                         }
 422
 423                         ALOGV("Sensor %d report available (%d bytes)\n", s,
 424                               sr_offset);
 425
 426                         sensor_info[s].report_ts = ts;
 427                         sensor_info[s].report_pending = 1;
 428                 }
 429
 430         return 0;
 431 }
 432
 433
 434 static int propagate_sensor_report(int s, struct sensors_event_t* data)
 435 {
 436         /* There's a sensor report pending for this sensor ; transmit it */
 437
 438         int catalog_index = sensor_info[s].catalog_index;
 439         int sensor_type = sensor_catalog[catalog_index].type;
 440         int num_fields;
 441         int c;
 442         unsigned char* current_sample;
 443         int64_t current_ts = get_timestamp();
 444         int64_t delta;
 445
 446         memset(data, 0, sizeof(sensors_event_t));
 447
 448         data->version = sizeof(sensors_event_t);
 449         data->sensor = s;
 450         data->type = sensor_type;
 451
 452         if (sensor_info[s].report_ts)
 453                 data->timestamp = sensor_info[s].report_ts;
 454         else
 455                 data->timestamp = current_ts;
 456
 457         switch (sensor_type) {
 458                 case SENSOR_TYPE_ACCELEROMETER:         /* m/s^2        */
 459                 case SENSOR_TYPE_MAGNETIC_FIELD:        /* micro-tesla  */
 460                 case SENSOR_TYPE_ORIENTATION:           /* degrees      */
 461                 case SENSOR_TYPE_GYROSCOPE:             /* radians/s    */
 462                         num_fields = 3;
 463                         break;
 464
 465                 case SENSOR_TYPE_LIGHT:                 /* SI lux units */
 466                 case SENSOR_TYPE_AMBIENT_TEMPERATURE:   /* °C          */
 467                 case SENSOR_TYPE_TEMPERATURE:           /* °C          */
 468                 case SENSOR_TYPE_PROXIMITY:             /* centimeters  */
 469                 case SENSOR_TYPE_PRESSURE:              /* hecto-pascal */
 470                 case SENSOR_TYPE_RELATIVE_HUMIDITY:     /* percent */
 471                         num_fields = 1;
 472                         break;
 473
 474                 case SENSOR_TYPE_ROTATION_VECTOR:
 475                         num_fields = 4;
 476                         break;
 477
 478                 case SENSOR_TYPE_DEVICE_PRIVATE_BASE:   /* Hidden for now */
 479                         return 0;                       /* Drop sample */
 480
 481                 default:
 482                         ALOGE("Unknown sensor type!\n");
 483                         return 0;                       /* Drop sample */
 484         }
 485
 486         ALOGV("Sample on sensor %d (type %d):\n", s, sensor_type);
 487
 488         /* Take note of current time counter value for rate control purposes */
 489         sensor_info[s].last_integration_ts = current_ts;
 490
 491         /* If we're dealing with a poll-mode sensor */
 492         if (!sensor_info[s].num_channels) {
 493
 494                 /* Read values through sysfs rather than from a report buffer */
 495                 for (c=0; c<num_fields; c++) {
 496
 497                         data->data[c] = acquire_immediate_value(s, c);
 498
 499                         ALOGV("\tfield %d: %f\n", c, data->data[c]);
 500                 }
 501
 502                 /* Control acquisition time and flag anything beyond 100 ms */
 503                 delta = get_timestamp() - current_ts;
 504
 505                 if (delta > 100 * 1000 * 1000) {
 506                         ALOGI("Sensor %d (%s) sampling time: %d ms\n", s,
 507                         sensor_info[s].friendly_name, (int) (delta / 1000000));
 508                 }
 509
 510                 return sensor_info[s].ops.finalize(s, data);
 511         }
 512
 513         /* Convert the data into the expected Android-level format */
 514
 515         current_sample = sensor_info[s].report_buffer;
 516
 517         for (c=0; c<num_fields; c++) {
 518
 519                 data->data[c] = sensor_info[s].ops.transform
 520                                                         (s, c, current_sample);
 521
 522                 ALOGV("\tfield %d: %f\n", c, data->data[c]);
 523                 current_sample += sensor_info[s].channel[c].size;
 524         }
 525
 526         /*
 527          * The finalize routine, in addition to its late sample processing duty,
 528          * has the final say on whether or not the sample gets sent to Android.
 529          */
 530         return sensor_info[s].ops.finalize(s, data);
 531 }
 532
 533
 534 static int get_poll_time (void)
 535 {
 536         int64_t target_ts;
 537         int64_t lowest_target_ts;
 538         int64_t current_ts;
 539         int s;
 540
 541         if (!active_poll_sensors)
 542                 return -1;      /* Infinite wait */
 543
 544         /* Check if we should schedule a poll-mode sensor event delivery */
 545
 546         lowest_target_ts = INT64_MAX;
 547
 548         for (s=0; s<sensor_count; s++)
 549                 if (sensor_info[s].enable_count &&
 550                     sensor_info[s].sampling_rate > 0 &&
 551                     !sensor_info[s].num_channels) {
 552                                 target_ts = sensor_info[s].last_integration_ts +
 553                                       1000000000LL/sensor_info[s].sampling_rate;
 554
 555                                 if (target_ts < lowest_target_ts)
 556                                         lowest_target_ts = target_ts;
 557                         }
 558
 559         if (lowest_target_ts == INT64_MAX)
 560                 return -1;
 561
 562         current_ts = get_timestamp();
 563
 564         if (lowest_target_ts <= current_ts)
 565                 return 0;
 566
 567         return (lowest_target_ts - current_ts)/1000000; /* ms */
 568 }
 569
 570
 571 static void acknowledge_release (void)
 572 {
 573         /* A write to our socket circuit was performed to release epoll */
 574         char buf;
 575         read(poll_socket_pair[0], &buf, 1);
 576 }
 577
 578
 579 int sensor_poll(struct sensors_event_t* data, int count)
 580 {
 581         int s;
 582         int i;
 583         int nfds;
 584         int delta;
 585         struct epoll_event ev[MAX_DEVICES];
 586         int64_t target_ts;
 587
 588         /* Get one or more events from our collection of sensors */
 589
 590 return_first_available_sensor_report:
 591
 592         /* If there's at least one available report */
 593         for (s=0; s<sensor_count; s++)
 594                 if (sensor_info[s].report_pending) {
 595
 596                         /* Lower flag */
 597                         sensor_info[s].report_pending = 0;
 598
 599                         if (propagate_sensor_report(s, data)) {
 600                                 /* Return that up */
 601                                 ALOGV("Report on sensor %d\n", s);
 602                                 return 1;
 603                         }
 604
 605                         /*
 606                          * If the sample was deemed invalid or unreportable,
 607                          * e.g. had the same value as the previously reported
 608                          * value for a 'on change' sensor, silently drop it
 609                          */
 610                 }
 611 await_event:
 612
 613         ALOGV("Awaiting sensor data\n");
 614
 615         nfds = epoll_wait(poll_fd, ev, MAX_DEVICES, get_poll_time());
 616
 617         last_poll_exit_ts = get_timestamp();
 618
 619         if (nfds == -1) {
 620                 ALOGI("epoll_wait returned -1 (%s)\n", strerror(errno));
 621                 goto await_event;
 622         }
 623
 624         ALOGV("%d fds signalled\n", nfds);
 625
 626         /* For each of the devices for which a report is available */
 627         for (i=0; i<nfds; i++)
 628                 if (ev[i].events == EPOLLIN) {
 629                         if (ev[i].data.u32 == INVALID_DEV_NUM) {
 630                                 acknowledge_release();
 631                                 goto await_event;
 632                         } else
 633                                 /* Read report */
 634                                 integrate_device_report(ev[i].data.u32);
 635                 }
 636
 637         /* Check poll-mode sensors and fire up an event if it's time to do so */
 638         if (active_poll_sensors)
 639                 for (s=0; s<sensor_count; s++)
 640                         if (sensor_info[s].enable_count &&
 641                             !sensor_info[s].num_channels &&
 642                             sensor_info[s].sampling_rate > 0) {
 643                                 target_ts = sensor_info[s].last_integration_ts +
 644                                       1000000000LL/sensor_info[s].sampling_rate;
 645
 646                                 if (last_poll_exit_ts >= target_ts)
 647                                         sensor_info[s].report_pending = 1;
 648                         }
 649
 650         goto return_first_available_sensor_report;
 651 }
 652
 653
 654 int sensor_set_delay(int s, int64_t ns)
 655 {
 656         /* Set the rate at which a specific sensor should report events */
 657
 658         /* See Android sensors.h for indication on sensor trigger modes */
 659
 660         char sysfs_path[PATH_MAX];
 661         char avail_sysfs_path[PATH_MAX];
 662         int dev_num             =       sensor_info[s].dev_num;
 663         int i                   =       sensor_info[s].catalog_index;
 664         const char *prefix      =       sensor_catalog[i].tag;
 665         float new_sampling_rate; /* Granted sampling rate after arbitration   */
 666         float cur_sampling_rate; /* Currently used sampling rate              */
 667         float req_sampling_rate; /* Requested ; may be different from granted */
 668         int per_sensor_sampling_rate;
 669         int per_device_sampling_rate;
 670         int max_supported_rate = 0;
 671         char freqs_buf[100];
 672         char* cursor;
 673         int n;
 674         int sr;
 675
 676         if (!ns) {
 677                 ALOGE("Rejecting zero delay request on sensor %d\n", s);
 678                 return -EINVAL;
 679         }
 680
 681         new_sampling_rate = req_sampling_rate = 1000000000L/ns;
 682
 683         if (new_sampling_rate < 1) {
 684                 ALOGI("Sub-HZ sampling rate requested on on sensor %d\n", s);
 685                 new_sampling_rate = 1;
 686         }
 687
 688         sensor_info[s].sampling_rate = new_sampling_rate;
 689
 690         /* If we're dealing with a poll-mode sensor, release poll and return */
 691         if (!sensor_info[s].num_channels)
 692                 goto exit;
 693
 694         sprintf(sysfs_path, SENSOR_SAMPLING_PATH, dev_num, prefix);
 695
 696         if (sysfs_read_float(sysfs_path, &cur_sampling_rate) != -1) {
 697                 per_sensor_sampling_rate = 1;
 698                 per_device_sampling_rate = 0;
 699         } else {
 700                 per_sensor_sampling_rate = 0;
 701
 702                 sprintf(sysfs_path, DEVICE_SAMPLING_PATH, dev_num);
 703
 704                 if (sysfs_read_float(sysfs_path, &cur_sampling_rate) != -1)
 705                         per_device_sampling_rate = 1;
 706                 else
 707                         per_device_sampling_rate = 0;
 708         }
 709
 710         if (!per_sensor_sampling_rate && !per_device_sampling_rate) {
 711                 ALOGE("No way to adjust sampling rate on sensor %d\n", s);
 712                 return -ENOSYS;
 713         }
 714
 715         /* Coordinate with others active sensors on the same device, if any */
 716         if (per_device_sampling_rate)
 717                 for (n=0; n<sensor_count; n++)
 718                         if (n != s && sensor_info[n].dev_num == dev_num &&
 719                             sensor_info[n].num_channels &&
 720                             sensor_info[n].enable_count &&
 721                             sensor_info[n].sampling_rate > new_sampling_rate)
 722                                 new_sampling_rate= sensor_info[n].sampling_rate;
 723
 724         /* Check if we have contraints on allowed sampling rates */
 725
 726         sprintf(avail_sysfs_path, DEVICE_AVAIL_FREQ_PATH, dev_num);
 727
 728         if (sysfs_read_str(avail_sysfs_path, freqs_buf, sizeof(freqs_buf)) > 0){
 729                 cursor = freqs_buf;
 730
 731                 /* Decode allowed sampling rates string, ex: "10 20 50 100" */
 732
 733                 /* While we're not at the end of the string */
 734                 while (*cursor && cursor[0]) {
 735
 736                         /* Decode a single value */
 737                         sr = strtod(cursor, NULL);
 738
 739                         /* Cap sampling rate to CAP_SENSOR_MAX_FREQUENCY*/
 740                         if (sr > CAP_SENSOR_MAX_FREQUENCY)
 741                                  break;
 742
 743                         if (sr > max_supported_rate)
 744                                 max_supported_rate = sr;
 745
 746                         /* If this matches the selected rate, we're happy */
 747                         if (new_sampling_rate == sr)
 748                                 break;
 749
 750                         /*
 751                          * If we reached a higher value than the desired rate,
 752                          * adjust selected rate so it matches the first higher
 753                          * available one and stop parsing - this makes the
 754                          * assumption that rates are sorted by increasing value
 755                          * in the allowed frequencies string.
 756                          */
 757                         if (sr > new_sampling_rate) {
 758                                 ALOGI(
 759                         "Increasing sampling rate on sensor %d from %g to %g\n",
 760                                 s, (double) req_sampling_rate, (double) sr);
 761
 762                                 new_sampling_rate = sr;
 763                                 break;
 764                         }
 765
 766                         /* Skip digits */
 767                         while (cursor[0] && !isspace(cursor[0]))
 768                                 cursor++;
 769
 770                         /* Skip spaces */
 771                         while (cursor[0] && isspace(cursor[0]))
 772                                         cursor++;
 773                 }
 774         }
 775
 776
 777         if (max_supported_rate &&
 778                 new_sampling_rate > max_supported_rate) {
 779                 new_sampling_rate = max_supported_rate;
 780                 ALOGI(  "Can't support %g sampling rate, lowering to %g\n",
 781                         (double) req_sampling_rate, (double) new_sampling_rate);
 782         }
 783
 784
 785         /* If the desired rate is already active we're all set */
 786         if (new_sampling_rate == cur_sampling_rate)
 787                 return 0;
 788
 789         ALOGI("Sensor %d sampling rate switched to %g\n", s, new_sampling_rate);
 790
 791         if (trig_sensors_per_dev[dev_num])
 792                 enable_buffer(dev_num, 0);
 793
 794         sysfs_write_float(sysfs_path, new_sampling_rate);
 795
 796         if (trig_sensors_per_dev[dev_num])
 797                 enable_buffer(dev_num, 1);
 798
 799 exit:
 800         /* Release the polling loop so an updated timeout value gets used */
 801         write(poll_socket_pair[1], "", 1);
 802
 803         return 0;
 804 }
 805
 806
 807
 808 int allocate_control_data (void)
 809 {
 810         int i;
 811         struct epoll_event ev = {0};
 812
 813         for (i=0; i<MAX_DEVICES; i++)
 814                 device_fd[i] = -1;
 815
 816         poll_fd = epoll_create(MAX_DEVICES);
 817
 818         if (poll_fd == -1) {
 819                 ALOGE("Can't create epoll instance for iio sensors!\n");
 820                 return -1;
 821         }
 822
 823         /* Create and add "unblocking" fd to the set of watched fds */
 824
 825         if (socketpair(AF_UNIX, SOCK_STREAM, 0, poll_socket_pair) == -1) {
 826                 ALOGE("Can't create socket pair for iio sensors!\n");
 827                 close(poll_fd);
 828                 return -1;
 829         }
 830
 831         ev.events = EPOLLIN;
 832         ev.data.u32 = INVALID_DEV_NUM;
 833
 834         epoll_ctl(poll_fd, EPOLL_CTL_ADD, poll_socket_pair[0], &ev);
 835
 836         return poll_fd;
 837 }
 838
 839
 840 void delete_control_data (void)
 841 {
 842 }