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                         (1024.0)
  25 #define NUMOFACCDATA                (8.0)
  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                   (1.0/6.6)
  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                   (1.0/64)
  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                (2000.0/32767*M_PI/180)
  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                                         M_PI/180)
 111 #define CONVERT_G_D_VTF16E14_Y(s,d,x)  (DEF_ORIENT_GYRO_Y *\
 112                                         convert_from_vtf_format(s,d,x) * \
 113                                         M_PI/180)
 114 #define CONVERT_G_D_VTF16E14_Z(s,d,x)  (DEF_ORIENT_GYRO_Z *\
 115                                         convert_from_vtf_format(s,d,x) * \
 116                                         M_PI/180)
 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 clamp_gyro_readings_to_zero (int s, struct sensors_event_t* data)
 193 {
 194         float x, y, z;
 195         float near_zero;
 196
 197         x = data->data[0];
 198         y = data->data[1];
 199         z = data->data[2];
 200
 201
 202         /* If we're calibrated, don't filter out as much */
 203         if (sensor[s].cal_level > 0)
 204                 near_zero = 0.02; /* rad/s */
 205         else
 206                 near_zero = 0.1;
 207
 208         /* If motion on all axes is small enough */
 209         if (fabs(x) < near_zero && fabs(y) < near_zero && fabs(z) < near_zero) {
 210
 211                 /*
 212                  * Report that we're not moving at all... but not exactly zero
 213                  * as composite sensors (orientation, rotation vector) don't
 214                  * seem to react very well to it.
 215                  */
 216
 217                 data->data[0] *= 0.000001;
 218                 data->data[1] *= 0.000001;
 219                 data->data[2] *= 0.000001;
 220         }
 221 }
 222
 223 static void process_event_gyro_uncal(int s, int i, struct sensors_event_t* data)
 224 {
 225         struct gyro_cal_t* gyro_data;
 226
 227         if (sensor[s].type == SENSOR_TYPE_GYROSCOPE) {
 228                 gyro_data = (struct gyro_cal_t*) sensor[s].cal_data;
 229
 230                 memcpy(&sensor[i].sample, data, sizeof(struct sensors_event_t));
 231
 232                 sensor[i].sample.type = SENSOR_TYPE_GYROSCOPE_UNCALIBRATED;
 233                 sensor[i].sample.sensor = s;
 234
 235                 sensor[i].sample.data[0] = data->data[0] + gyro_data->bias_x;
 236                 sensor[i].sample.data[1] = data->data[1] + gyro_data->bias_y;
 237                 sensor[i].sample.data[2] = data->data[2] + gyro_data->bias_z;
 238
 239                 sensor[i].sample.uncalibrated_gyro.bias[0] = gyro_data->bias_x;
 240                 sensor[i].sample.uncalibrated_gyro.bias[1] = gyro_data->bias_y;
 241                 sensor[i].sample.uncalibrated_gyro.bias[2] = gyro_data->bias_z;
 242
 243                 sensor[i].report_pending = 1;
 244         }
 245 }
 246
 247 static void process_event(int s, struct sensors_event_t* data)
 248 {
 249         /*
 250          * This gets the real event (post process - calibration, filtering & co.)
 251          * and makes it into a virtual one.
 252          * The specific processing function for each sensor will populate the
 253          * necessary fields and set up the report pending flag.
 254          */
 255
 256          int i;
 257
 258          /* Go through out virtual sensors and check if we can use this event */
 259          for (i = 0; i < sensor_count; i++) {
 260                 switch (sensor[i].type) {
 261                         case SENSOR_TYPE_GYROSCOPE_UNCALIBRATED:
 262                                 process_event_gyro_uncal(s, i, data);
 263                         break;
 264
 265                         default:
 266                         break;
 267                 }
 268         }
 269 }
 270
 271 static int finalize_sample_default (int s, struct sensors_event_t* data)
 272 {
 273         /* Swap fields if we have a custom channel ordering on this sensor */
 274         if (sensor[s].quirks & QUIRK_FIELD_ORDERING)
 275                 reorder_fields(data->data, sensor[s].order);
 276
 277         sensor[s].event_count++;
 278         switch (sensor[s].type) {
 279                 case SENSOR_TYPE_ACCELEROMETER:
 280                         /* Always consider the accelerometer accurate */
 281                         data->acceleration.status = SENSOR_STATUS_ACCURACY_HIGH;
 282                         if (sensor[s].quirks & QUIRK_NOISY)
 283                                 denoise(s, data);
 284                         break;
 285
 286                 case SENSOR_TYPE_MAGNETIC_FIELD:
 287                         calibrate_compass (data, &sensor[s]);
 288                         if (sensor[s].quirks & QUIRK_NOISY)
 289                                 denoise(s, data);
 290                         break;
 291
 292                 case SENSOR_TYPE_GYROSCOPE:
 293
 294                         /*
 295                          * Report medium accuracy by default ; higher accuracy
 296                          * levels will be reported once, and if, we achieve
 297                          * calibration.
 298                          */
 299                         data->gyro.status = SENSOR_STATUS_ACCURACY_MEDIUM;
 300
 301                         /*
 302                          * We're only trying to calibrate data from continuously
 303                          * firing gyroscope drivers, as motion based ones use
 304                          * movement thresholds that may lead us to incorrectly
 305                          * estimate bias.
 306                          */
 307                         if (sensor[s].selected_trigger !=
 308                                 sensor[s].motion_trigger_name)
 309                                         calibrate_gyro(data, &sensor[s]);
 310
 311                         /*
 312                          * For noisy sensors drop a few samples to make sure we
 313                          * have at least GYRO_MIN_SAMPLES events in the
 314                          * filtering queue. This improves mean and std dev.
 315                          */
 316                         if (sensor[s].quirks & QUIRK_NOISY) {
 317                                 if (sensor[s].selected_trigger !=
 318                                     sensor[s].motion_trigger_name &&
 319                                     sensor[s].event_count<GYRO_MIN_SAMPLES)
 320                                                 return 0;
 321
 322                                 denoise(s, data);
 323                         }
 324
 325                         /* Clamp near zero moves to (0,0,0) if appropriate */
 326                         clamp_gyro_readings_to_zero(s, data);
 327                         break;
 328
 329                 case SENSOR_TYPE_LIGHT:
 330                 case SENSOR_TYPE_AMBIENT_TEMPERATURE:
 331                 case SENSOR_TYPE_TEMPERATURE:
 332                         /* Only keep two decimals for these readings */
 333                         data->data[0] = 0.01 * ((int) (data->data[0] * 100));
 334
 335                         /* ... fall through ... */
 336
 337                 case SENSOR_TYPE_PROXIMITY:
 338                         /*
 339                          * These are on change sensors ; drop the sample if it
 340                          * has the same value as the previously reported one.
 341                          */
 342                         if (data->data[0] == sensor[s].prev_val)
 343                                 return 0;
 344
 345                         sensor[s].prev_val = data->data[0];
 346                         break;
 347         }
 348         /* If there are active virtual sensors depending on this one - process the event */
 349         if (sensor[s].ref_count)
 350                 process_event(s, data);
 351         /* We will drop samples if the sensor is not directly enabled */
 352         if (!sensor[s].directly_enabled)
 353                 return 0;
 354
 355         return 1; /* Return sample to Android */
 356 }
 357
 358
 359 static float transform_sample_default(int s, int c, unsigned char* sample_data)
 360 {
 361         struct datum_info_t* sample_type = &sensor[s].channel[c].type_info;
 362         int64_t              s64 = sample_as_int64(sample_data, sample_type);
 363         float scale = sensor[s].scale ?
 364                         sensor[s].scale : sensor[s].channel[c].scale;
 365
 366         /* In case correction has been requested using properties, apply it */
 367         scale *= sensor[s].channel[c].opt_scale;
 368
 369         /* Apply default scaling rules */
 370         return (sensor[s].offset + s64) * scale;
 371 }
 372
 373
 374 static int finalize_sample_ISH (int s, struct sensors_event_t* data)
 375 {
 376         float pitch, roll, yaw;
 377
 378         /* Swap fields if we have a custom channel ordering on this sensor */
 379         if (sensor[s].quirks & QUIRK_FIELD_ORDERING)
 380                 reorder_fields(data->data, sensor[s].order);
 381
 382         if (sensor[s].type == SENSOR_TYPE_ORIENTATION) {
 383
 384                 pitch = data->data[0];
 385                 roll = data->data[1];
 386                 yaw = data->data[2];
 387
 388                 data->data[0] = 360.0 - yaw;
 389                 data->data[1] = -pitch;
 390                 data->data[2] = -roll;
 391         }
 392
 393         /* Add this event to our global records, for filtering purposes */
 394         record_sample(s, data);
 395
 396         return 1; /* Return sample to Android */
 397 }
 398
 399
 400 static float transform_sample_ISH (int s, int c, unsigned char* sample_data)
 401 {
 402         struct datum_info_t* sample_type = &sensor[s].channel[c].type_info;
 403         int val         = (int) sample_as_int64(sample_data, sample_type);
 404         float correction;
 405         int data_bytes  = (sample_type->realbits)/8;
 406         int exponent    = sensor[s].offset;
 407
 408         /* In case correction has been requested using properties, apply it */
 409         correction = sensor[s].channel[c].opt_scale;
 410
 411         switch (sensor[s].type) {
 412                 case SENSOR_TYPE_ACCELEROMETER:
 413                         switch (c) {
 414                                 case 0:
 415                                         return  correction *
 416                                                 CONVERT_A_G_VTF16E14_X(
 417                                                 data_bytes, exponent, val);
 418
 419                                 case 1:
 420                                         return  correction *
 421                                                 CONVERT_A_G_VTF16E14_Y(
 422                                                 data_bytes, exponent, val);
 423
 424                                 case 2:
 425                                         return  correction *
 426                                                 CONVERT_A_G_VTF16E14_Z(
 427                                                 data_bytes, exponent, val);
 428                         }
 429                         break;
 430
 431
 432                 case SENSOR_TYPE_GYROSCOPE:
 433                         switch (c) {
 434                                 case 0:
 435                                         return  correction *
 436                                                 CONVERT_G_D_VTF16E14_X(
 437                                                 data_bytes, exponent, val);
 438
 439                                 case 1:
 440                                         return  correction *
 441                                                 CONVERT_G_D_VTF16E14_Y(
 442                                                 data_bytes, exponent, val);
 443
 444                                 case 2:
 445                                         return  correction *
 446                                                 CONVERT_G_D_VTF16E14_Z(
 447                                                 data_bytes, exponent, val);
 448                         }
 449                         break;
 450
 451                 case SENSOR_TYPE_MAGNETIC_FIELD:
 452                         switch (c) {
 453                                 case 0:
 454                                         return  correction *
 455                                                 CONVERT_M_MG_VTF16E14_X(
 456                                                 data_bytes, exponent, val);
 457
 458                                 case 1:
 459                                         return  correction *
 460                                                 CONVERT_M_MG_VTF16E14_Y(
 461                                                 data_bytes, exponent, val);
 462
 463                                 case 2:
 464                                         return  correction *
 465                                                 CONVERT_M_MG_VTF16E14_Z(
 466                                                 data_bytes, exponent, val);
 467                         }
 468                         break;
 469
 470                 case SENSOR_TYPE_LIGHT:
 471                                 return (float) val;
 472
 473                 case SENSOR_TYPE_ORIENTATION:
 474                         return  correction * convert_from_vtf_format(
 475                                                 data_bytes, exponent, val);
 476
 477                 case SENSOR_TYPE_ROTATION_VECTOR:
 478                         return  correction * convert_from_vtf_format(
 479                                                 data_bytes, exponent, val);
 480         }
 481
 482         return 0;
 483 }
 484
 485
 486 void select_transform (int s)
 487 {
 488         char prop_name[PROP_NAME_MAX];
 489         char prop_val[PROP_VALUE_MAX];
 490         int i                   = sensor[s].catalog_index;
 491         const char *prefix      = sensor_catalog[i].tag;
 492
 493         sprintf(prop_name, PROP_BASE, prefix, "transform");
 494
 495         if (property_get(prop_name, prop_val, "")) {
 496                 if (!strcmp(prop_val, "ISH")) {
 497                         ALOGI(  "Using Intel Sensor Hub semantics on %s\n",
 498                                 sensor[s].friendly_name);
 499
 500                         sensor[s].ops.transform = transform_sample_ISH;
 501                         sensor[s].ops.finalize = finalize_sample_ISH;
 502                         return;
 503                 }
 504         }
 505
 506         sensor[s].ops.transform = transform_sample_default;
 507         sensor[s].ops.finalize = finalize_sample_default;
 508 }
 509
 510
 511 float acquire_immediate_value(int s, int c)
 512 {
 513         char sysfs_path[PATH_MAX];
 514         float val;
 515         int ret;
 516         int dev_num = sensor[s].dev_num;
 517         int i = sensor[s].catalog_index;
 518         const char* raw_path = sensor_catalog[i].channel[c].raw_path;
 519         const char* input_path = sensor_catalog[i].channel[c].input_path;
 520         float scale = sensor[s].scale ?
 521                         sensor[s].scale : sensor[s].channel[c].scale;
 522         float offset = sensor[s].offset;
 523         int sensor_type = sensor_catalog[i].type;
 524         float correction;
 525
 526         /* In case correction has been requested using properties, apply it */
 527         correction = sensor[s].channel[c].opt_scale;
 528
 529         /* Acquire a sample value for sensor s / channel c through sysfs */
 530
 531         if (input_path[0]) {
 532                 sprintf(sysfs_path, BASE_PATH "%s", dev_num, input_path);
 533                 ret = sysfs_read_float(sysfs_path, &val);
 534
 535                 if (!ret) {
 536                         return val * correction;
 537                 }
 538         };
 539
 540         if (!raw_path[0])
 541                 return 0;
 542
 543         sprintf(sysfs_path, BASE_PATH "%s", dev_num, raw_path);
 544         ret = sysfs_read_float(sysfs_path, &val);
 545
 546         if (ret == -1)
 547                 return 0;
 548
 549         /*
 550          * There is no transform ops defined yet for raw sysfs values.
 551          * Use this function to perform transformation as well.
 552          */
 553         if (sensor_type == SENSOR_TYPE_MAGNETIC_FIELD)
 554                 return  CONVERT_GAUSS_TO_MICROTESLA ((val + offset) * scale) *
 555                         correction;
 556
 557         return (val + offset) * scale * correction;
 558 }