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 int finalize_sample_default (int s, struct sensors_event_t* data)
 265 {
 266         /* Swap fields if we have a custom channel ordering on this sensor */
 267         if (sensor_info[s].quirks & QUIRK_FIELD_ORDERING)
 268                 reorder_fields(data->data, sensor_info[s].order);
 269
 270         sensor_info[s].event_count++;
 271         switch (sensor_info[s].type) {
 272                 case SENSOR_TYPE_ACCELEROMETER:
 273                         /* Always consider the accelerometer accurate */
 274                         data->acceleration.status = SENSOR_STATUS_ACCURACY_HIGH;
 275                         if (sensor_info[s].quirks & QUIRK_NOISY)
 276                                 denoise(&sensor_info[s], data, 3, 20);
 277                         break;
 278
 279                 case SENSOR_TYPE_MAGNETIC_FIELD:
 280                         calibrate_compass (data, &sensor_info[s], get_timestamp());
 281                         if (sensor_info[s].quirks & QUIRK_NOISY)
 282                                 denoise(&sensor_info[s], data, 3, 100);
 283                         break;
 284
 285                 case SENSOR_TYPE_GYROSCOPE:
 286                 case SENSOR_TYPE_GYROSCOPE_UNCALIBRATED:
 287                         /*
 288                          * Report medium accuracy by default ; higher accuracy
 289                          * levels will be reported once, and if, we achieve
 290                          * calibration.
 291                          */
 292                         data->gyro.status = SENSOR_STATUS_ACCURACY_MEDIUM;
 293
 294                         /*
 295                          * We're only trying to calibrate data from continuously
 296                          * firing gyroscope drivers, as motion based ones use
 297                          * movement thresholds that may lead us to incorrectly
 298                          * estimate bias.
 299                          */
 300                         if (sensor_info[s].selected_trigger !=
 301                                 sensor_info[s].motion_trigger_name)
 302                                         calibrate_gyro(data, &sensor_info[s]);
 303
 304                         /* For noisy sensors we'll drop a very few number
 305                          * of samples to make sure we have at least MIN_SAMPLES events
 306                          * in the filtering queue. This is to make sure we are not sending
 307                          * events that can disturb our mean or stddev.
 308                          */
 309                         if (sensor_info[s].quirks & QUIRK_NOISY) {
 310                                 denoise_median(&sensor_info[s], data, 3);
 311                                 if((sensor_info[s].selected_trigger !=
 312                                         sensor_info[s].motion_trigger_name) &&
 313                                         sensor_info[s].event_count < MIN_SAMPLES)
 314                                                 return 0;
 315                         }
 316                         break;
 317
 318                 case SENSOR_TYPE_LIGHT:
 319                 case SENSOR_TYPE_AMBIENT_TEMPERATURE:
 320                 case SENSOR_TYPE_TEMPERATURE:
 321                         /* Only keep two decimals for these readings */
 322                         data->data[0] = 0.01 * ((int) (data->data[0] * 100));
 323
 324                         /* ... fall through ... */
 325
 326                 case SENSOR_TYPE_PROXIMITY:
 327                         /*
 328                          * These are on change sensors ; drop the sample if it
 329                          * has the same value as the previously reported one.
 330                          */
 331                         if (data->data[0] == sensor_info[s].prev_val)
 332                                 return 0;
 333
 334                         sensor_info[s].prev_val = data->data[0];
 335                         break;
 336         }
 337
 338         return 1; /* Return sample to Android */
 339 }
 340
 341
 342 static float transform_sample_default(int s, int c, unsigned char* sample_data)
 343 {
 344         struct datum_info_t* sample_type = &sensor_info[s].channel[c].type_info;
 345         int64_t              s64 = sample_as_int64(sample_data, sample_type);
 346         float scale = sensor_info[s].scale ?
 347                         sensor_info[s].scale : sensor_info[s].channel[c].scale;
 348
 349         /* In case correction has been requested using properties, apply it */
 350         scale *= sensor_info[s].channel[c].opt_scale;
 351
 352         /* Apply default scaling rules */
 353         return (sensor_info[s].offset + s64) * scale;
 354 }
 355
 356
 357 static int finalize_sample_ISH (int s, struct sensors_event_t* data)
 358 {
 359         float pitch, roll, yaw;
 360
 361         /* Swap fields if we have a custom channel ordering on this sensor */
 362         if (sensor_info[s].quirks & QUIRK_FIELD_ORDERING)
 363                 reorder_fields(data->data, sensor_info[s].order);
 364
 365         if (sensor_info[s].type == SENSOR_TYPE_ORIENTATION) {
 366
 367                 pitch = data->data[0];
 368                 roll = data->data[1];
 369                 yaw = data->data[2];
 370
 371                 data->data[0] = 360.0 - yaw;
 372                 data->data[1] = -pitch;
 373                 data->data[2] = -roll;
 374         }
 375
 376         return 1; /* Return sample to Android */
 377 }
 378
 379
 380 static float transform_sample_ISH (int s, int c, unsigned char* sample_data)
 381 {
 382         struct datum_info_t* sample_type = &sensor_info[s].channel[c].type_info;
 383         int val         = (int) sample_as_int64(sample_data, sample_type);
 384         float correction;
 385         int data_bytes  = (sample_type->realbits)/8;
 386         int exponent    = sensor_info[s].offset;
 387
 388         /* In case correction has been requested using properties, apply it */
 389         correction = sensor_info[s].channel[c].opt_scale;
 390
 391         switch (sensor_info[s].type) {
 392                 case SENSOR_TYPE_ACCELEROMETER:
 393                         switch (c) {
 394                                 case 0:
 395                                         return  correction *
 396                                                 CONVERT_A_G_VTF16E14_X(
 397                                                 data_bytes, exponent, val);
 398
 399                                 case 1:
 400                                         return  correction *
 401                                                 CONVERT_A_G_VTF16E14_Y(
 402                                                 data_bytes, exponent, val);
 403
 404                                 case 2:
 405                                         return  correction *
 406                                                 CONVERT_A_G_VTF16E14_Z(
 407                                                 data_bytes, exponent, val);
 408                         }
 409                         break;
 410
 411
 412                 case SENSOR_TYPE_GYROSCOPE:
 413                         switch (c) {
 414                                 case 0:
 415                                         return  correction *
 416                                                 CONVERT_G_D_VTF16E14_X(
 417                                                 data_bytes, exponent, val);
 418
 419                                 case 1:
 420                                         return  correction *
 421                                                 CONVERT_G_D_VTF16E14_Y(
 422                                                 data_bytes, exponent, val);
 423
 424                                 case 2:
 425                                         return  correction *
 426                                                 CONVERT_G_D_VTF16E14_Z(
 427                                                 data_bytes, exponent, val);
 428                         }
 429                         break;
 430
 431                 case SENSOR_TYPE_MAGNETIC_FIELD:
 432                         switch (c) {
 433                                 case 0:
 434                                         return  correction *
 435                                                 CONVERT_M_MG_VTF16E14_X(
 436                                                 data_bytes, exponent, val);
 437
 438                                 case 1:
 439                                         return  correction *
 440                                                 CONVERT_M_MG_VTF16E14_Y(
 441                                                 data_bytes, exponent, val);
 442
 443                                 case 2:
 444                                         return  correction *
 445                                                 CONVERT_M_MG_VTF16E14_Z(
 446                                                 data_bytes, exponent, val);
 447                         }
 448                         break;
 449
 450                 case SENSOR_TYPE_LIGHT:
 451                                 return (float) val;
 452
 453                 case SENSOR_TYPE_ORIENTATION:
 454                         return  correction * convert_from_vtf_format(
 455                                                 data_bytes, exponent, val);
 456
 457                 case SENSOR_TYPE_ROTATION_VECTOR:
 458                         return  correction * convert_from_vtf_format(
 459                                                 data_bytes, exponent, val);
 460         }
 461
 462         return 0;
 463 }
 464
 465
 466 void select_transform (int s)
 467 {
 468         char prop_name[PROP_NAME_MAX];
 469         char prop_val[PROP_VALUE_MAX];
 470         int i                   = sensor_info[s].catalog_index;
 471         const char *prefix      = sensor_catalog[i].tag;
 472
 473         sprintf(prop_name, PROP_BASE, prefix, "transform");
 474
 475         if (property_get(prop_name, prop_val, "")) {
 476                 if (!strcmp(prop_val, "ISH")) {
 477                         ALOGI(  "Using Intel Sensor Hub semantics on %s\n",
 478                                 sensor_info[s].friendly_name);
 479
 480                         sensor_info[s].ops.transform = transform_sample_ISH;
 481                         sensor_info[s].ops.finalize = finalize_sample_ISH;
 482                         return;
 483                 }
 484         }
 485
 486         sensor_info[s].ops.transform = transform_sample_default;
 487         sensor_info[s].ops.finalize = finalize_sample_default;
 488 }
 489
 490
 491 float acquire_immediate_value(int s, int c)
 492 {
 493         char sysfs_path[PATH_MAX];
 494         float val;
 495         int ret;
 496         int dev_num = sensor_info[s].dev_num;
 497         int i = sensor_info[s].catalog_index;
 498         const char* raw_path = sensor_catalog[i].channel[c].raw_path;
 499         const char* input_path = sensor_catalog[i].channel[c].input_path;
 500         float scale = sensor_info[s].scale ?
 501                         sensor_info[s].scale : sensor_info[s].channel[c].scale;
 502         float offset = sensor_info[s].offset;
 503         int sensor_type = sensor_catalog[i].type;
 504         float correction;
 505
 506         /* In case correction has been requested using properties, apply it */
 507         correction = sensor_info[s].channel[c].opt_scale;
 508
 509         /* Acquire a sample value for sensor s / channel c through sysfs */
 510
 511         if (input_path[0]) {
 512                 sprintf(sysfs_path, BASE_PATH "%s", dev_num, input_path);
 513                 ret = sysfs_read_float(sysfs_path, &val);
 514
 515                 if (!ret) {
 516                         return val * correction;
 517                 }
 518         };
 519
 520         if (!raw_path[0])
 521                 return 0;
 522
 523         sprintf(sysfs_path, BASE_PATH "%s", dev_num, raw_path);
 524         ret = sysfs_read_float(sysfs_path, &val);
 525
 526         if (ret == -1)
 527                 return 0;
 528
 529         /*
 530         There is no transform ops defined yet for Raw sysfs values
 531         Use this function to perform transformation as well.
 532         */
 533         if (sensor_type == SENSOR_TYPE_MAGNETIC_FIELD)
 534                 return  CONVERT_GAUSS_TO_MICROTESLA ((val + offset) * scale) *
 535                         correction;
 536
 537         return (val + offset) * scale * correction;
 538 }