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