transform.c

   1 /*
   2  * Copyright (C) 2014 Intel Corporation.
   3  */
   4
   5 #include <stdlib.h>
   6 #include <math.h>
   7 #include <utils/Log.h>
   8 #include <cutils/properties.h>
   9 #include <hardware/sensors.h>
  10 #include "calibration.h"
  11 #include "common.h"
  12 #include "description.h"
  13 #include "transform.h"
  14 #include "utils.h"
  15 #include "filtering.h"
  16
  17 /*----------------------------------------------------------------------------*/
  18
  19 /* Macros related to Intel Sensor Hub */
  20
  21 #define GRAVITY 9.80665f
  22
  23 /* 720 LSG = 1G */
  24 #define LSG                         (1024.0f)
  25 #define NUMOFACCDATA                (8.0f)
  26
  27 /* conversion of acceleration data to SI units (m/s^2) */
  28 #define CONVERT_A                   (GRAVITY_EARTH / LSG / NUMOFACCDATA)
  29 #define CONVERT_A_X(x)              ((float(x)/1000) * (GRAVITY * -1.0))
  30 #define CONVERT_A_Y(x)              ((float(x)/1000) * (GRAVITY * 1.0))
  31 #define CONVERT_A_Z(x)              ((float(x)/1000) * (GRAVITY * 1.0))
  32
  33 /* conversion of magnetic data to uT units */
  34 #define CONVERT_M                   (1.0f/6.6f)
  35 #define CONVERT_M_X                 (-CONVERT_M)
  36 #define CONVERT_M_Y                 (-CONVERT_M)
  37 #define CONVERT_M_Z                 (CONVERT_M)
  38
  39 #define CONVERT_GAUSS_TO_MICROTESLA(x)        ( (x) * 100 )
  40
  41 /* conversion of orientation data to degree units */
  42 #define CONVERT_O                   (1.0f/64.0f)
  43 #define CONVERT_O_A                 (CONVERT_O)
  44 #define CONVERT_O_P                 (CONVERT_O)
  45 #define CONVERT_O_R                 (-CONVERT_O)
  46
  47 /*conversion of gyro data to SI units (radian/sec) */
  48 #define CONVERT_GYRO                ((2000.0f/32767.0f)*((float)M_PI / 180.0f))
  49 #define CONVERT_GYRO_X              (-CONVERT_GYRO)
  50 #define CONVERT_GYRO_Y              (-CONVERT_GYRO)
  51 #define CONVERT_GYRO_Z              (CONVERT_GYRO)
  52
  53 #define BIT(x) (1 << (x))
  54
  55 inline unsigned int set_bit_range(int start, int end)
  56 {
  57     int i;
  58     unsigned int value = 0;
  59
  60     for (i = start; i < end; ++i)
  61         value |= BIT(i);
  62     return value;
  63 }
  64
  65 inline float convert_from_vtf_format(int size, int exponent, unsigned int value)
  66 {
  67     int divider=1;
  68     int i;
  69     float sample;
  70     int mul = 1.0;
  71
  72     value = value & set_bit_range(0, size*8);
  73     if (value & BIT(size*8-1)) {
  74         value =  ((1LL << (size*8)) - value);
  75         mul = -1.0;
  76     }
  77     sample = value * 1.0;
  78     if (exponent < 0) {
  79         exponent = abs(exponent);
  80         for (i = 0; i < exponent; ++i) {
  81             divider = divider*10;
  82         }
  83         return mul * sample/divider;
  84     } else {
  85         return mul * sample * pow(10.0, exponent);
  86     }
  87 }
  88
  89 // Platform sensor orientation
  90 #define DEF_ORIENT_ACCEL_X                   -1
  91 #define DEF_ORIENT_ACCEL_Y                   -1
  92 #define DEF_ORIENT_ACCEL_Z                   -1
  93
  94 #define DEF_ORIENT_GYRO_X                   1
  95 #define DEF_ORIENT_GYRO_Y                   1
  96 #define DEF_ORIENT_GYRO_Z                   1
  97
  98 // G to m/s2
  99 #define CONVERT_FROM_VTF16(s,d,x)      (convert_from_vtf_format(s,d,x))
 100 #define CONVERT_A_G_VTF16E14_X(s,d,x)  (DEF_ORIENT_ACCEL_X *\
 101                                         convert_from_vtf_format(s,d,x)*GRAVITY)
 102 #define CONVERT_A_G_VTF16E14_Y(s,d,x)  (DEF_ORIENT_ACCEL_Y *\
 103                                         convert_from_vtf_format(s,d,x)*GRAVITY)
 104 #define CONVERT_A_G_VTF16E14_Z(s,d,x)  (DEF_ORIENT_ACCEL_Z *\
 105                                         convert_from_vtf_format(s,d,x)*GRAVITY)
 106
 107 // Degree/sec to radian/sec
 108 #define CONVERT_G_D_VTF16E14_X(s,d,x)  (DEF_ORIENT_GYRO_X *\
 109                                         convert_from_vtf_format(s,d,x) * \
 110                                         ((float)M_PI/180.0f))
 111 #define CONVERT_G_D_VTF16E14_Y(s,d,x)  (DEF_ORIENT_GYRO_Y *\
 112                                         convert_from_vtf_format(s,d,x) * \
 113                                         ((float)M_PI/180.0f))
 114 #define CONVERT_G_D_VTF16E14_Z(s,d,x)  (DEF_ORIENT_GYRO_Z *\
 115                                         convert_from_vtf_format(s,d,x) * \
 116                                         ((float)M_PI/180.0f))
 117
 118 // Milli gauss to micro tesla
 119 #define CONVERT_M_MG_VTF16E14_X(s,d,x) (convert_from_vtf_format(s,d,x)/10)
 120 #define CONVERT_M_MG_VTF16E14_Y(s,d,x) (convert_from_vtf_format(s,d,x)/10)
 121 #define CONVERT_M_MG_VTF16E14_Z(s,d,x) (convert_from_vtf_format(s,d,x)/10)
 122
 123
 124 /*----------------------------------------------------------------------------*/
 125
 126 static int64_t sample_as_int64(unsigned char* sample, struct datum_info_t* type)
 127 {
 128         uint64_t u64;
 129         int i;
 130         int zeroed_bits = type->storagebits - type->realbits;
 131         uint64_t sign_mask;
 132         uint64_t value_mask;
 133
 134         u64 = 0;
 135
 136         if (type->endianness == 'b')
 137                 for (i=0; i<type->storagebits/8; i++)
 138                         u64 = (u64 << 8) | sample[i];
 139         else
 140                 for (i=type->storagebits/8 - 1; i>=0; i--)
 141                         u64 = (u64 << 8) | sample[i];
 142
 143         u64 = (u64 >> type->shift) & (~0ULL >> zeroed_bits);
 144
 145         if (type->sign == 'u')
 146                 return (int64_t) u64; /* We don't handle unsigned 64 bits int */
 147
 148         /* Signed integer */
 149
 150         switch (type->realbits) {
 151                 case 0 ... 1:
 152                         return 0;
 153
 154                 case 8:
 155                         return (int64_t) (int8_t) u64;
 156
 157                 case 16:
 158                         return (int64_t) (int16_t) u64;
 159
 160                 case 32:
 161                         return (int64_t) (int32_t) u64;
 162
 163                 case 64:
 164                         return (int64_t) u64;
 165
 166                 default:
 167                         sign_mask = 1 << (type->realbits-1);
 168                         value_mask = sign_mask - 1;
 169
 170                         if (u64 & sign_mask)
 171                                 /* Negative value: return 2-complement */
 172                                 return - ((~u64 & value_mask) + 1);
 173                         else
 174                                 return (int64_t) u64; /* Positive value */
 175         }
 176 }
 177
 178
 179 static void reorder_fields(float* data, unsigned char map[MAX_CHANNELS])
 180 {
 181         int i;
 182         float temp[MAX_CHANNELS];
 183
 184         for (i=0; i<MAX_CHANNELS; i++)
 185                 temp[i] = data[map[i]];
 186
 187         for (i=0; i<MAX_CHANNELS; i++)
 188                 data[i] = temp[i];
 189 }
 190
 191
 192 static void denoise (struct sensor_info_t* si, struct sensors_event_t* data,
 193                      int num_fields, int max_samples)
 194 {
 195         /*
 196          * Smooth out incoming data using a moving average over a number of
 197          * samples. We accumulate one second worth of samples, or max_samples,
 198          * depending on which is lower.
 199          */
 200
 201         int i;
 202         int f;
 203         int sampling_rate = (int) si->sampling_rate;
 204         int history_size;
 205         int history_full = 0;
 206
 207         /* Don't denoise anything if we have less than two samples per second */
 208         if (sampling_rate < 2)
 209                 return;
 210
 211         /* Restrict window size to the min of sampling_rate and max_samples */
 212         if (sampling_rate > max_samples)
 213                 history_size = max_samples;
 214         else
 215                 history_size = sampling_rate;
 216
 217         /* Reset history if we're operating on an incorrect window size */
 218         if (si->history_size != history_size) {
 219                 si->history_size = history_size;
 220                 si->history_entries = 0;
 221                 si->history_index = 0;
 222                 si->history = (float*) realloc(si->history,
 223                                 si->history_size * num_fields * sizeof(float));
 224                 if (si->history) {
 225                         si->history_sum = (float*) realloc(si->history_sum,
 226                                 num_fields * sizeof(float));
 227                         if (si->history_sum)
 228                                 memset(si->history_sum, 0, num_fields * sizeof(float));
 229                 }
 230         }
 231
 232         if (!si->history || !si->history_sum)
 233                 return; /* Unlikely, but still... */
 234
 235         /* Update initialized samples count */
 236         if (si->history_entries < si->history_size)
 237                 si->history_entries++;
 238         else
 239                 history_full = 1;
 240
 241         /* Record new sample and calculate the moving sum */
 242         for (f=0; f < num_fields; f++) {
 243                 /**
 244                  * A field is going to be overwritten if
 245                  * history is full, so decrease the history sum
 246                  */
 247                 if (history_full)
 248                         si->history_sum[f] -=
 249                                 si->history[si->history_index * num_fields + f];
 250
 251                 si->history[si->history_index * num_fields + f] = data->data[f];
 252                 si->history_sum[f] += data->data[f];
 253
 254                 /* For now simply compute a mobile mean for each field */
 255                 /* and output filtered data */
 256                 data->data[f] = si->history_sum[f] / si->history_entries;
 257         }
 258
 259         /* Update our rolling index (next evicted cell) */
 260         si->history_index = (si->history_index + 1) % si->history_size;
 261 }
 262
 263
 264 static void clamp_gyro_readings_to_zero (int s, struct sensors_event_t* data)
 265 {
 266         float x, y, z;
 267         float near_zero;
 268
 269         switch (sensor_info[s].type) {
 270                 case SENSOR_TYPE_GYROSCOPE:
 271                         x = data->data[0];
 272                         y = data->data[1];
 273                         z = data->data[2];
 274                         break;
 275
 276                 case SENSOR_TYPE_GYROSCOPE_UNCALIBRATED:
 277                         x = data->data[0] - data->uncalibrated_gyro.bias[0];
 278                         y = data->data[1] - data->uncalibrated_gyro.bias[1];
 279                         z = data->data[2] - data->uncalibrated_gyro.bias[2];
 280                         break;
 281
 282                 default:
 283                         return;
 284         }
 285
 286         /* If we're calibrated, don't filter out as much */
 287         if (sensor_info[s].cal_level > 0)
 288                 near_zero = 0.02; /* rad/s */
 289         else
 290                 near_zero = 0.1;
 291
 292         /* If motion on all axes is small enough */
 293         if (fabs(x) < near_zero && fabs(y) < near_zero && fabs(z) < near_zero) {
 294
 295                 /*
 296                  * Report that we're not moving at all... but not exactly zero
 297                  * as composite sensors (orientation, rotation vector) don't
 298                  * seem to react very well to it.
 299                  */
 300                 switch (sensor_info[s].type) {
 301                         case SENSOR_TYPE_GYROSCOPE:
 302                                 data->data[0] *= 0.000001;
 303                                 data->data[1] *= 0.000001;
 304                                 data->data[2] *= 0.000001;
 305                                 break;
 306
 307                         case SENSOR_TYPE_GYROSCOPE_UNCALIBRATED:
 308                                 data->data[0]= data->uncalibrated_gyro.bias[0]
 309                                                 + 0.000001 * x;
 310                                 data->data[1]= data->uncalibrated_gyro.bias[1]
 311                                                 + 0.000001 * y;
 312                                 data->data[2]= data->uncalibrated_gyro.bias[2]
 313                                                 + 0.000001 * z;
 314                                 break;
 315                 }
 316         }
 317 }
 318
 319
 320 static int finalize_sample_default (int s, struct sensors_event_t* data)
 321 {
 322         /* Swap fields if we have a custom channel ordering on this sensor */
 323         if (sensor_info[s].quirks & QUIRK_FIELD_ORDERING)
 324                 reorder_fields(data->data, sensor_info[s].order);
 325
 326         sensor_info[s].event_count++;
 327         switch (sensor_info[s].type) {
 328                 case SENSOR_TYPE_ACCELEROMETER:
 329                         /* Always consider the accelerometer accurate */
 330                         data->acceleration.status = SENSOR_STATUS_ACCURACY_HIGH;
 331                         if (sensor_info[s].quirks & QUIRK_NOISY)
 332                                 denoise(&sensor_info[s], data, 3, 20);
 333                         break;
 334
 335                 case SENSOR_TYPE_MAGNETIC_FIELD:
 336                         calibrate_compass (data, &sensor_info[s], get_timestamp());
 337                         if (sensor_info[s].quirks & QUIRK_NOISY)
 338                                 denoise(&sensor_info[s], data, 3, 30);
 339                         break;
 340
 341                 case SENSOR_TYPE_GYROSCOPE:
 342
 343                         /*
 344                          * Report medium accuracy by default ; higher accuracy
 345                          * levels will be reported once, and if, we achieve
 346                          * calibration.
 347                          */
 348                         data->gyro.status = SENSOR_STATUS_ACCURACY_MEDIUM;
 349
 350                         /* ... fall through */
 351
 352                 case SENSOR_TYPE_GYROSCOPE_UNCALIBRATED:
 353
 354                         /*
 355                          * We're only trying to calibrate data from continuously
 356                          * firing gyroscope drivers, as motion based ones use
 357                          * movement thresholds that may lead us to incorrectly
 358                          * estimate bias.
 359                          */
 360                         if (sensor_info[s].selected_trigger !=
 361                                 sensor_info[s].motion_trigger_name)
 362                                         calibrate_gyro(data, &sensor_info[s]);
 363
 364                         /* For noisy sensors we'll drop a very few number
 365                          * of samples to make sure we have at least MIN_SAMPLES events
 366                          * in the filtering queue. This is to make sure we are not sending
 367                          * events that can disturb our mean or stddev.
 368                          */
 369                         if (sensor_info[s].quirks & QUIRK_NOISY) {
 370                                 denoise_median(&sensor_info[s], data, 3);
 371                                 if((sensor_info[s].selected_trigger !=
 372                                         sensor_info[s].motion_trigger_name) &&
 373                                         sensor_info[s].event_count < MIN_SAMPLES)
 374                                                 return 0;
 375                         }
 376
 377                         /* Clamp near zero moves to (0,0,0) if appropriate */
 378                         clamp_gyro_readings_to_zero(s, data);
 379                         break;
 380
 381                 case SENSOR_TYPE_LIGHT:
 382                 case SENSOR_TYPE_AMBIENT_TEMPERATURE:
 383                 case SENSOR_TYPE_TEMPERATURE:
 384                         /* Only keep two decimals for these readings */
 385                         data->data[0] = 0.01 * ((int) (data->data[0] * 100));
 386
 387                         /* ... fall through ... */
 388
 389                 case SENSOR_TYPE_PROXIMITY:
 390                         /*
 391                          * These are on change sensors ; drop the sample if it
 392                          * has the same value as the previously reported one.
 393                          */
 394                         if (data->data[0] == sensor_info[s].prev_val)
 395                                 return 0;
 396
 397                         sensor_info[s].prev_val = data->data[0];
 398                         break;
 399         }
 400
 401         /* Add this event to our global records, for filtering purposes */
 402         record_sample(s, data);
 403
 404         return 1; /* Return sample to Android */
 405 }
 406
 407
 408 static float transform_sample_default(int s, int c, unsigned char* sample_data)
 409 {
 410         struct datum_info_t* sample_type = &sensor_info[s].channel[c].type_info;
 411         int64_t              s64 = sample_as_int64(sample_data, sample_type);
 412         float scale = sensor_info[s].scale ?
 413                         sensor_info[s].scale : sensor_info[s].channel[c].scale;
 414
 415         /* In case correction has been requested using properties, apply it */
 416         scale *= sensor_info[s].channel[c].opt_scale;
 417
 418         /* Apply default scaling rules */
 419         return (sensor_info[s].offset + s64) * scale;
 420 }
 421
 422
 423 static int finalize_sample_ISH (int s, struct sensors_event_t* data)
 424 {
 425         float pitch, roll, yaw;
 426
 427         /* Swap fields if we have a custom channel ordering on this sensor */
 428         if (sensor_info[s].quirks & QUIRK_FIELD_ORDERING)
 429                 reorder_fields(data->data, sensor_info[s].order);
 430
 431         if (sensor_info[s].type == SENSOR_TYPE_ORIENTATION) {
 432
 433                 pitch = data->data[0];
 434                 roll = data->data[1];
 435                 yaw = data->data[2];
 436
 437                 data->data[0] = 360.0 - yaw;
 438                 data->data[1] = -pitch;
 439                 data->data[2] = -roll;
 440         }
 441
 442         /* Add this event to our global records, for filtering purposes */
 443         record_sample(s, data);
 444
 445         return 1; /* Return sample to Android */
 446 }
 447
 448
 449 static float transform_sample_ISH (int s, int c, unsigned char* sample_data)
 450 {
 451         struct datum_info_t* sample_type = &sensor_info[s].channel[c].type_info;
 452         int val         = (int) sample_as_int64(sample_data, sample_type);
 453         float correction;
 454         int data_bytes  = (sample_type->realbits)/8;
 455         int exponent    = sensor_info[s].offset;
 456
 457         /* In case correction has been requested using properties, apply it */
 458         correction = sensor_info[s].channel[c].opt_scale;
 459
 460         switch (sensor_info[s].type) {
 461                 case SENSOR_TYPE_ACCELEROMETER:
 462                         switch (c) {
 463                                 case 0:
 464                                         return  correction *
 465                                                 CONVERT_A_G_VTF16E14_X(
 466                                                 data_bytes, exponent, val);
 467
 468                                 case 1:
 469                                         return  correction *
 470                                                 CONVERT_A_G_VTF16E14_Y(
 471                                                 data_bytes, exponent, val);
 472
 473                                 case 2:
 474                                         return  correction *
 475                                                 CONVERT_A_G_VTF16E14_Z(
 476                                                 data_bytes, exponent, val);
 477                         }
 478                         break;
 479
 480
 481                 case SENSOR_TYPE_GYROSCOPE:
 482                         switch (c) {
 483                                 case 0:
 484                                         return  correction *
 485                                                 CONVERT_G_D_VTF16E14_X(
 486                                                 data_bytes, exponent, val);
 487
 488                                 case 1:
 489                                         return  correction *
 490                                                 CONVERT_G_D_VTF16E14_Y(
 491                                                 data_bytes, exponent, val);
 492
 493                                 case 2:
 494                                         return  correction *
 495                                                 CONVERT_G_D_VTF16E14_Z(
 496                                                 data_bytes, exponent, val);
 497                         }
 498                         break;
 499
 500                 case SENSOR_TYPE_MAGNETIC_FIELD:
 501                         switch (c) {
 502                                 case 0:
 503                                         return  correction *
 504                                                 CONVERT_M_MG_VTF16E14_X(
 505                                                 data_bytes, exponent, val);
 506
 507                                 case 1:
 508                                         return  correction *
 509                                                 CONVERT_M_MG_VTF16E14_Y(
 510                                                 data_bytes, exponent, val);
 511
 512                                 case 2:
 513                                         return  correction *
 514                                                 CONVERT_M_MG_VTF16E14_Z(
 515                                                 data_bytes, exponent, val);
 516                         }
 517                         break;
 518
 519                 case SENSOR_TYPE_LIGHT:
 520                                 return (float) val;
 521
 522                 case SENSOR_TYPE_ORIENTATION:
 523                         return  correction * convert_from_vtf_format(
 524                                                 data_bytes, exponent, val);
 525
 526                 case SENSOR_TYPE_ROTATION_VECTOR:
 527                         return  correction * convert_from_vtf_format(
 528                                                 data_bytes, exponent, val);
 529         }
 530
 531         return 0;
 532 }
 533
 534
 535 void select_transform (int s)
 536 {
 537         char prop_name[PROP_NAME_MAX];
 538         char prop_val[PROP_VALUE_MAX];
 539         int i                   = sensor_info[s].catalog_index;
 540         const char *prefix      = sensor_catalog[i].tag;
 541
 542         sprintf(prop_name, PROP_BASE, prefix, "transform");
 543
 544         if (property_get(prop_name, prop_val, "")) {
 545                 if (!strcmp(prop_val, "ISH")) {
 546                         ALOGI(  "Using Intel Sensor Hub semantics on %s\n",
 547                                 sensor_info[s].friendly_name);
 548
 549                         sensor_info[s].ops.transform = transform_sample_ISH;
 550                         sensor_info[s].ops.finalize = finalize_sample_ISH;
 551                         return;
 552                 }
 553         }
 554
 555         sensor_info[s].ops.transform = transform_sample_default;
 556         sensor_info[s].ops.finalize = finalize_sample_default;
 557 }
 558
 559
 560 float acquire_immediate_value(int s, int c)
 561 {
 562         char sysfs_path[PATH_MAX];
 563         float val;
 564         int ret;
 565         int dev_num = sensor_info[s].dev_num;
 566         int i = sensor_info[s].catalog_index;
 567         const char* raw_path = sensor_catalog[i].channel[c].raw_path;
 568         const char* input_path = sensor_catalog[i].channel[c].input_path;
 569         float scale = sensor_info[s].scale ?
 570                         sensor_info[s].scale : sensor_info[s].channel[c].scale;
 571         float offset = sensor_info[s].offset;
 572         int sensor_type = sensor_catalog[i].type;
 573         float correction;
 574
 575         /* In case correction has been requested using properties, apply it */
 576         correction = sensor_info[s].channel[c].opt_scale;
 577
 578         /* Acquire a sample value for sensor s / channel c through sysfs */
 579
 580         if (input_path[0]) {
 581                 sprintf(sysfs_path, BASE_PATH "%s", dev_num, input_path);
 582                 ret = sysfs_read_float(sysfs_path, &val);
 583
 584                 if (!ret) {
 585                         return val * correction;
 586                 }
 587         };
 588
 589         if (!raw_path[0])
 590                 return 0;
 591
 592         sprintf(sysfs_path, BASE_PATH "%s", dev_num, raw_path);
 593         ret = sysfs_read_float(sysfs_path, &val);
 594
 595         if (ret == -1)
 596                 return 0;
 597
 598         /*
 599         There is no transform ops defined yet for Raw sysfs values
 600         Use this function to perform transformation as well.
 601         */
 602         if (sensor_type == SENSOR_TYPE_MAGNETIC_FIELD)
 603                 return  CONVERT_GAUSS_TO_MICROTESLA ((val + offset) * scale) *
 604                         correction;
 605
 606         return (val + offset) * scale * correction;
 607 }