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
 151         ALOGI("Found %d channels on iio device %d\n", known_channels, dev_num);
 152
 153         /*
 154          * Now that we know which channels are defined, their sizes and their
 155          * ordering, update channels offsets within device report. Note: there
 156          * is a possibility that several sensors share the same index, with
 157          * their data fields being isolated by masking and shifting as specified
 158          * through the real bits and shift values in type attributes. This case
 159          * is not currently supported. Also, the code below assumes no hole in
 160          * the sequence of indices, so it is dependent on discovery of all
 161          * sensors.
 162          */
 163          offset = 0;
 164          for (i=0; i<MAX_SENSORS * MAX_CHANNELS; i++) {
 165                 s =     sensor_handle_from_index[i];
 166                 c =     channel_number_from_index[i];
 167                 size =  channel_size_from_index[i];
 168
 169                 if (!size)
 170                         continue;
 171
 172                 ALOGI("S%d C%d : offset %d, size %d, type %s\n",
 173                       s, c, offset, size, sensor_info[s].channel[c].type_spec);
 174
 175                 sensor_info[s].channel[c].offset        = offset;
 176                 sensor_info[s].channel[c].size          = size;
 177
 178                 offset += size;
 179          }
 180 }
 181
 182
 183 int adjust_counters (int s, int enabled)
 184 {
 185         /*
 186          * Adjust counters based on sensor enable action. Return values are:
 187          * -1 if there's an inconsistency: abort action in this case
 188          *  0 if the operation was completed and we're all set
 189          *  1 if we toggled the state of the sensor and there's work left
 190          */
 191
 192         int dev_num = sensor_info[s].dev_num;
 193         int catalog_index = sensor_info[s].catalog_index;
 194         int sensor_type = sensor_catalog[catalog_index].type;
 195
 196         /* Refcount per sensor, in terms of enable count */
 197         if (enabled) {
 198                 ALOGI("Enabling sensor %d (iio device %d: %s)\n",
 199                         s, dev_num, sensor_info[s].friendly_name);
 200
 201                 sensor_info[s].enable_count++;
 202
 203                 if (sensor_info[s].enable_count != 1) {
 204                         return 0; /* The sensor was, and remains, in use */
 205                 } else {
 206                         if (sensor_type == SENSOR_TYPE_MAGNETIC_FIELD)
 207                                 compass_read_data(COMPASS_CALIBRATION_PATH);
 208                 }
 209         } else {
 210                 if (sensor_info[s].enable_count == 0)
 211                         return -1; /* Spurious disable call */
 212
 213                 ALOGI("Disabling sensor %d (iio device %d: %s)\n", s, dev_num,
 214                       sensor_info[s].friendly_name);
 215
 216                 if (sensor_type == SENSOR_TYPE_MAGNETIC_FIELD)
 217                         compass_store_data(COMPASS_CALIBRATION_PATH);
 218
 219                 sensor_info[s].enable_count--;
 220
 221                 if (sensor_info[s].enable_count > 0)
 222                         return 0; /* The sensor was, and remains, in use */
 223
 224                 /* Sensor disabled, lower report available flag */
 225                 sensor_info[s].report_pending = 0;
 226         }
 227
 228         /* We changed the state of a sensor - adjust per iio device counters */
 229
 230         /* If this is a regular event-driven sensor */
 231         if (sensor_info[s].num_channels) {
 232
 233                         if (enabled)
 234                                 trig_sensors_per_dev[dev_num]++;
 235                         else
 236                                 trig_sensors_per_dev[dev_num]--;
 237
 238                         return 1;
 239                 }
 240
 241         if (enabled) {
 242                 active_poll_sensors++;
 243                 poll_sensors_per_dev[dev_num]++;
 244                 return 1;
 245         }
 246
 247         active_poll_sensors--;
 248         poll_sensors_per_dev[dev_num]--;
 249         return 1;
 250 }
 251
 252
 253 int sensor_activate(int s, int enabled)
 254 {
 255         char sysfs_path[PATH_MAX];
 256         char device_name[PATH_MAX];
 257         char trigger_name[MAX_NAME_SIZE + 16];
 258         int c;
 259         struct epoll_event ev = {0};
 260         int dev_fd;
 261         int ret;
 262         int dev_num = sensor_info[s].dev_num;
 263         int i = sensor_info[s].catalog_index;
 264         int is_poll_sensor = !sensor_info[s].num_channels;
 265
 266         ret = adjust_counters(s, enabled);
 267
 268         /* If the operation was neutral in terms of state, we're done */
 269         if (ret <= 0)
 270                 return ret;
 271
 272         if (!is_poll_sensor) {
 273
 274                 /* Stop sampling */
 275                 enable_buffer(dev_num, 0);
 276                 setup_trigger(dev_num, "\n");
 277
 278                 /* Turn channels associated to this sensor on or off */
 279                  for (c=0;c<sensor_info[s].num_channels; c++) {
 280                         sprintf(sysfs_path, CHANNEL_PATH "%s",
 281                                 sensor_info[s].dev_num,
 282                                 sensor_catalog[i].channel[c].en_path);
 283
 284                         sysfs_write_int(sysfs_path, enabled);
 285                 }
 286
 287                 /* If there's at least one sensor enabled on this iio device */
 288                 if (trig_sensors_per_dev[dev_num]) {
 289                         sprintf(trigger_name, "%s-dev%d",
 290                                         sensor_info[s].internal_name, dev_num);
 291
 292                         /* Start sampling */
 293                         setup_trigger(dev_num, trigger_name);
 294                         enable_buffer(dev_num, 1);
 295                 }
 296         }
 297
 298         /*
 299          * Make sure we have a fd on the character device ; conversely, close
 300          * the fd if no one is using associated sensor anymore. The assumption
 301          * here is that the underlying driver will power on the relevant
 302          * hardware block while someone hold a fd on the device.
 303          */
 304         dev_fd = device_fd[dev_num];
 305
 306         if (!enabled) {
 307                 if (dev_fd != -1 && !poll_sensors_per_dev[dev_num] &&
 308                         !trig_sensors_per_dev[dev_num]) {
 309                                 /*
 310                                  * Stop watching this fd. This should be a no-op
 311                                  * in case this fd was not in the poll set.
 312                                  */
 313                                 epoll_ctl(poll_fd, EPOLL_CTL_DEL, dev_fd, NULL);
 314
 315                                 close(dev_fd);
 316                                 device_fd[dev_num] = -1;
 317                         }
 318                 return 0;
 319         }
 320
 321         if (dev_fd == -1) {
 322                 /* First enabled sensor on this iio device */
 323                 sprintf(device_name, DEV_FILE_PATH, dev_num);
 324                 dev_fd = open(device_name, O_RDONLY | O_NONBLOCK);
 325
 326                 device_fd[dev_num] = dev_fd;
 327
 328                 if (dev_fd == -1) {
 329                         ALOGE("Could not open fd on %s (%s)\n",
 330                               device_name, strerror(errno));
 331                         adjust_counters(s, 0);
 332                         return -1;
 333                 }
 334
 335                 ALOGV("Opened %s: fd=%d\n", device_name, dev_fd);
 336
 337                 if (!is_poll_sensor) {
 338
 339                         /* Add this iio device fd to the set of watched fds */
 340                         ev.events = EPOLLIN;
 341                         ev.data.u32 = dev_num;
 342
 343                         ret = epoll_ctl(poll_fd, EPOLL_CTL_ADD, dev_fd, &ev);
 344
 345                         if (ret == -1) {
 346                                 ALOGE(  "Failed adding %d to poll set (%s)\n",
 347                                         dev_fd, strerror(errno));
 348                                 return -1;
 349                         }
 350
 351                         /* Note: poll-mode fds are not readable */
 352                 }
 353         }
 354
 355         /* Release the polling loop so an updated timeout gets used */
 356         write(poll_socket_pair[1], "", 1);
 357
 358         return 0;
 359 }
 360
 361
 362 static int integrate_device_report(int dev_num)
 363 {
 364         int len;
 365         int s,c;
 366         unsigned char buf[MAX_SENSOR_REPORT_SIZE * MAX_SENSORS] = { 0 };
 367         int sr_offset;
 368         unsigned char *target;
 369         unsigned char *source;
 370         int size;
 371         int expected_size = 0;
 372
 373         /* There's an incoming report on the specified fd */
 374
 375         if (dev_num < 0 || dev_num >= MAX_DEVICES) {
 376                 ALOGE("Event reported on unexpected iio device %d\n", dev_num);
 377                 return -1;
 378         }
 379
 380         if (device_fd[dev_num] == -1) {
 381                 ALOGE("Ignoring stale report on iio device %d\n", dev_num);
 382                 return -1;
 383         }
 384
 385         for (s=0; s<MAX_SENSORS; s++)
 386                 if (sensor_info[s].dev_num == dev_num)
 387                         for (c=0; c<sensor_info[s].num_channels; c++)
 388                                 expected_size += sensor_info[s].channel[c].size;
 389
 390         len = read(device_fd[dev_num], buf, expected_size);
 391
 392         if (len == -1) {
 393                 ALOGE("Could not read report from iio device %d (%s)\n",
 394                       dev_num, strerror(errno));
 395                 return -1;
 396         }
 397
 398         ALOGV("Read %d bytes from iio device %d\n", len, dev_num);
 399
 400         for (s=0; s<MAX_SENSORS; s++)
 401                 if (sensor_info[s].dev_num == dev_num &&
 402                     sensor_info[s].enable_count) {
 403
 404                         sr_offset = 0;
 405
 406                         /* Copy data from device to sensor report buffer */
 407                         for (c=0; c<sensor_info[s].num_channels; c++) {
 408
 409                                 target = sensor_info[s].report_buffer +
 410                                         sr_offset;
 411
 412                                 source = buf + sensor_info[s].channel[c].offset;
 413
 414                                 size = sensor_info[s].channel[c].size;
 415
 416                                 memcpy(target, source, size);
 417
 418                                 sr_offset += size;
 419                         }
 420
 421                         ALOGV("Sensor %d report available (%d bytes)\n", s,
 422                               sr_offset);
 423
 424                         sensor_info[s].report_pending = 1;
 425                 }
 426
 427         return 0;
 428 }
 429
 430
 431 static void propagate_sensor_report(int s, struct sensors_event_t* data)
 432 {
 433         /* There's a sensor report pending for this sensor ; transmit it */
 434
 435         int catalog_index = sensor_info[s].catalog_index;
 436         int sensor_type = sensor_catalog[catalog_index].type;
 437         int num_fields;
 438         int c;
 439         unsigned char* current_sample;
 440         int64_t current_ts = get_timestamp();
 441
 442         memset(data, 0, sizeof(sensors_event_t));
 443
 444         data->version = sizeof(sensors_event_t);
 445         data->sensor = s;
 446         data->type = sensor_type;
 447         data->timestamp = current_ts;
 448
 449         switch (sensor_type) {
 450                 case SENSOR_TYPE_ACCELEROMETER:         /* m/s^2        */
 451                 case SENSOR_TYPE_MAGNETIC_FIELD:        /* micro-tesla  */
 452                 case SENSOR_TYPE_ORIENTATION:           /* degrees      */
 453                 case SENSOR_TYPE_GYROSCOPE:             /* radians/s    */
 454                         num_fields = 3;
 455                         break;
 456
 457                 case SENSOR_TYPE_LIGHT:                 /* SI lux units */
 458                 case SENSOR_TYPE_AMBIENT_TEMPERATURE:   /* °C          */
 459                 case SENSOR_TYPE_TEMPERATURE:           /* °C          */
 460                 case SENSOR_TYPE_PROXIMITY:             /* centimeters  */
 461                 case SENSOR_TYPE_PRESSURE:              /* hecto-pascal */
 462                 case SENSOR_TYPE_RELATIVE_HUMIDITY:     /* percent */
 463                         num_fields = 1;
 464                         break;
 465
 466                 case SENSOR_TYPE_ROTATION_VECTOR:
 467                         num_fields = 4;
 468                         break;
 469
 470                 case SENSOR_TYPE_DEVICE_PRIVATE_BASE:   /* hidden for now */
 471                         num_fields = 0;
 472                         break;
 473
 474                 default:
 475                         ALOGE("Unknown sensor type!\n");
 476                         num_fields = 0;
 477                         break;
 478         }
 479
 480         ALOGV("Sample on sensor %d (type %d):\n", s, sensor_type);
 481
 482         /* Take note of current time counter value for rate control purposes */
 483         sensor_info[s].last_integration_ts = current_ts;
 484
 485         /* If we're dealing with a poll-mode sensor */
 486         if (!sensor_info[s].num_channels) {
 487
 488                 /* Read values through sysfs rather than from a report buffer */
 489                 for (c=0; c<num_fields; c++) {
 490
 491                         data->data[c] = acquire_immediate_value(s, c);
 492
 493                         ALOGV("\tfield %d: %f\n", c, data->data[c]);
 494                 }
 495
 496                 sensor_info[s].ops.finalize(s, data);
 497                 return;
 498         }
 499
 500         /* Convert the data into the expected Android-level format */
 501
 502         current_sample = sensor_info[s].report_buffer;
 503
 504         for (c=0; c<num_fields; c++) {
 505
 506                 data->data[c] = sensor_info[s].ops.transform
 507                                                         (s, c, current_sample);
 508
 509                 ALOGV("\tfield %d: %f\n", c, data->data[c]);
 510                 current_sample += sensor_info[s].channel[c].size;
 511         }
 512
 513         sensor_info[s].ops.finalize(s, data);
 514 }
 515
 516
 517 static int get_poll_time (void)
 518 {
 519         int64_t target_ts;
 520         int64_t lowest_target_ts;
 521         int64_t current_ts;
 522         int s;
 523
 524         if (!active_poll_sensors)
 525                 return -1;      /* Infinite wait */
 526
 527         /* Check if we should schedule a poll-mode sensor event delivery */
 528
 529         lowest_target_ts = INT64_MAX;
 530
 531         for (s=0; s<sensor_count; s++)
 532                 if (sensor_info[s].enable_count &&
 533                     sensor_info[s].sampling_rate &&
 534                     !sensor_info[s].num_channels) {
 535                                 target_ts = sensor_info[s].last_integration_ts +
 536                                       1000000000LL/sensor_info[s].sampling_rate;
 537
 538                                 if (target_ts < lowest_target_ts)
 539                                         lowest_target_ts = target_ts;
 540                         }
 541
 542         if (lowest_target_ts == INT64_MAX)
 543                 return -1;
 544
 545         current_ts = get_timestamp();
 546
 547         if (lowest_target_ts <= current_ts)
 548                 return 0;
 549
 550         return (lowest_target_ts - current_ts)/1000000; /* ms */
 551 }
 552
 553
 554 static void acknowledge_release (void)
 555 {
 556         /* A write to our socket circuit was performed to release epoll */
 557         char buf;
 558         read(poll_socket_pair[0], &buf, 1);
 559 }
 560
 561
 562 int sensor_poll(struct sensors_event_t* data, int count)
 563 {
 564         int s;
 565         int i;
 566         int nfds;
 567         int delta;
 568         struct epoll_event ev[MAX_DEVICES];
 569         int64_t target_ts;
 570
 571         /* Get one or more events from our collection of sensors */
 572
 573 return_first_available_sensor_report:
 574
 575         /* If there's at least one available report */
 576         for (s=0; s<sensor_count; s++)
 577                 if (sensor_info[s].report_pending) {
 578
 579                         /* Return that up */
 580                         propagate_sensor_report(s, data);
 581                         sensor_info[s].report_pending = 0;
 582                         ALOGV("Report on sensor %d\n", s);
 583                         return 1;
 584                 }
 585 await_event:
 586
 587         ALOGV("Awaiting sensor data\n");
 588
 589         nfds = epoll_wait(poll_fd, ev, MAX_DEVICES, get_poll_time());
 590
 591         last_poll_exit_ts = get_timestamp();
 592
 593         if (nfds == -1) {
 594                 ALOGI("epoll_wait returned -1 (%s)\n", strerror(errno));
 595                 goto await_event;
 596         }
 597
 598         ALOGV("%d fds signalled\n", nfds);
 599
 600         /* For each of the devices for which a report is available */
 601         for (i=0; i<nfds; i++)
 602                 if (ev[i].events == EPOLLIN) {
 603                         if (ev[i].data.u32 == INVALID_DEV_NUM) {
 604                                 acknowledge_release();
 605                                 goto await_event;
 606                         } else
 607                                 /* Read report */
 608                                 integrate_device_report(ev[i].data.u32);
 609                 }
 610
 611         /* Check poll-mode sensors and fire up an event if it's time to do so */
 612         if (active_poll_sensors)
 613                 for (s=0; s<sensor_count; s++)
 614                         if (sensor_info[s].enable_count &&
 615                             !sensor_info[s].num_channels &&
 616                             sensor_info[s].sampling_rate) {
 617                                 target_ts = sensor_info[s].last_integration_ts +
 618                                       1000000000LL/sensor_info[s].sampling_rate;
 619
 620                                 if (last_poll_exit_ts >= target_ts)
 621                                         sensor_info[s].report_pending = 1;
 622                         }
 623
 624         goto return_first_available_sensor_report;
 625 }
 626
 627
 628 int sensor_set_delay(int s, int64_t ns)
 629 {
 630         /* Set the rate at which a specific sensor should report events */
 631
 632         /* See Android sensors.h for indication on sensor trigger modes */
 633
 634         char sysfs_path[PATH_MAX];
 635         char avail_sysfs_path[PATH_MAX];
 636         int dev_num             =       sensor_info[s].dev_num;
 637         int i                   =       sensor_info[s].catalog_index;
 638         const char *prefix      =       sensor_catalog[i].tag;
 639         int new_sampling_rate;  /* Granted sampling rate after arbitration   */
 640         int cur_sampling_rate;  /* Currently used sampling rate              */
 641         int req_sampling_rate;  /* Requested ; may be different from granted */
 642         int per_sensor_sampling_rate;
 643         int per_device_sampling_rate;
 644         int max_supported_rate = 0;
 645         int limit;
 646         char freqs_buf[100];
 647         char* cursor;
 648         int n;
 649
 650         if (!ns) {
 651                 ALOGE("Rejecting zero delay request on sensor %d\n", s);
 652                 return -EINVAL;
 653         }
 654
 655         new_sampling_rate = req_sampling_rate = (int) (1000000000L/ns);
 656
 657         if (!new_sampling_rate) {
 658                 ALOGI("Sub-HZ sampling rate requested on on sensor %d\n", s);
 659                 new_sampling_rate = 1;
 660         }
 661
 662         sensor_info[s].sampling_rate = new_sampling_rate;
 663
 664         /* If we're dealing with a poll-mode sensor, release poll and return */
 665         if (!sensor_info[s].num_channels)
 666                 goto exit;
 667
 668         sprintf(sysfs_path, SENSOR_SAMPLING_PATH, dev_num, prefix);
 669
 670         if (sysfs_read_int(sysfs_path, &cur_sampling_rate) != -1) {
 671                 per_sensor_sampling_rate = 1;
 672                 per_device_sampling_rate = 0;
 673         } else {
 674                 per_sensor_sampling_rate = 0;
 675
 676                 sprintf(sysfs_path, DEVICE_SAMPLING_PATH, dev_num);
 677
 678                 if (sysfs_read_int(sysfs_path, &cur_sampling_rate) != -1)
 679                         per_device_sampling_rate = 1;
 680                 else
 681                         per_device_sampling_rate = 0;
 682         }
 683
 684         if (!per_sensor_sampling_rate && !per_device_sampling_rate) {
 685                 ALOGE("No way to adjust sampling rate on sensor %d\n", s);
 686                 return -ENOSYS;
 687         }
 688
 689         /* Coordinate with others active sensors on the same device, if any */
 690         if (per_device_sampling_rate)
 691                 for (n=0; n<sensor_count; n++)
 692                         if (n != s && sensor_info[n].dev_num == dev_num &&
 693                             sensor_info[n].num_channels &&
 694                             sensor_info[n].enable_count &&
 695                             sensor_info[n].sampling_rate > new_sampling_rate)
 696                                 new_sampling_rate= sensor_info[n].sampling_rate;
 697
 698         /* Check if we have contraints on allowed sampling rates */
 699
 700         sprintf(avail_sysfs_path, DEVICE_AVAIL_FREQ_PATH, dev_num);
 701
 702         if (sysfs_read_str(avail_sysfs_path, freqs_buf, sizeof(freqs_buf)) > 0){
 703                 cursor = freqs_buf;
 704
 705                 /* Decode allowed sampling rates string, ex: "10 20 50 100" */
 706
 707                 /* While we're not at the end of the string */
 708                 while (*cursor && cursor[0]) {
 709
 710                         /* Decode a single integer value */
 711                         n = atoi(cursor);
 712
 713                         if (n > max_supported_rate)
 714                                 max_supported_rate = n;
 715
 716                         /* If this matches the selected rate, we're happy */
 717                         if (new_sampling_rate == n)
 718                                 break;
 719
 720                         /*
 721                          * If we reached a higher value than the desired rate,
 722                          * adjust selected rate so it matches the first higher
 723                          * available one and stop parsing - this makes the
 724                          * assumption that rates are sorted by increasing value
 725                          * in the allowed frequencies string.
 726                          */
 727                         if (n > new_sampling_rate) {
 728                                 ALOGI(
 729                         "Increasing sampling rate on sensor %d from %d to %d\n",
 730                                 s, req_sampling_rate, n);
 731
 732                                 new_sampling_rate = n;
 733                                 break;
 734                         }
 735
 736                         /* Skip digits */
 737                         while (cursor[0] && !isspace(cursor[0]))
 738                                 cursor++;
 739
 740                         /* Skip spaces */
 741                         while (cursor[0] && isspace(cursor[0]))
 742                                         cursor++;
 743                 }
 744         }
 745
 746         /* Cap sampling rate at 1000 events per second for now*/
 747
 748         limit = 1000;
 749
 750         if (max_supported_rate && new_sampling_rate > max_supported_rate)
 751                 limit = max_supported_rate;
 752
 753         if (new_sampling_rate > limit) {
 754
 755                 new_sampling_rate = limit;
 756
 757                 ALOGI(  "Can't support %d sampling rate, lowering to %d\n",
 758                         req_sampling_rate, new_sampling_rate);
 759         }
 760
 761         /* If the desired rate is already active we're all set */
 762         if (new_sampling_rate == cur_sampling_rate)
 763                 return 0;
 764
 765         ALOGI("Sensor %d sampling rate switched to %d\n", s, new_sampling_rate);
 766
 767         if (trig_sensors_per_dev[dev_num])
 768                 enable_buffer(dev_num, 0);
 769
 770         sysfs_write_int(sysfs_path, new_sampling_rate);
 771
 772         if (trig_sensors_per_dev[dev_num])
 773                 enable_buffer(dev_num, 1);
 774
 775 exit:
 776         /* Release the polling loop so an updated timeout value gets used */
 777         write(poll_socket_pair[1], "", 1);
 778
 779         return 0;
 780 }
 781
 782
 783
 784 int allocate_control_data (void)
 785 {
 786         int i;
 787         struct epoll_event ev = {0};
 788
 789         for (i=0; i<MAX_DEVICES; i++)
 790                 device_fd[i] = -1;
 791
 792         poll_fd = epoll_create(MAX_DEVICES);
 793
 794         if (poll_fd == -1) {
 795                 ALOGE("Can't create epoll instance for iio sensors!\n");
 796                 return -1;
 797         }
 798
 799         /* Create and add "unblocking" fd to the set of watched fds */
 800
 801         if (socketpair(AF_UNIX, SOCK_STREAM, 0, poll_socket_pair) == -1) {
 802                 ALOGE("Can't create socket pair for iio sensors!\n");
 803                 close(poll_fd);
 804                 return -1;
 805         }
 806
 807         ev.events = EPOLLIN;
 808         ev.data.u32 = INVALID_DEV_NUM;
 809
 810         epoll_ctl(poll_fd, EPOLL_CTL_ADD, poll_socket_pair[0], &ev);
 811
 812         return poll_fd;
 813 }
 814
 815
 816 void delete_control_data (void)
 817 {
 818 }