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
  16 /*----------------------------------------------------------------------------*/
  17
  18 /* Macros related to Intel Sensor Hub */
  19
  20 #define GRAVITY 9.80665f
  21
  22 /* 720 LSG = 1G */
  23 #define LSG                         (1024.0f)
  24 #define NUMOFACCDATA                (8.0f)
  25
  26 /* conversion of acceleration data to SI units (m/s^2) */
  27 #define CONVERT_A                   (GRAVITY_EARTH / LSG / NUMOFACCDATA)
  28 #define CONVERT_A_X(x)              ((float(x)/1000) * (GRAVITY * -1.0))
  29 #define CONVERT_A_Y(x)              ((float(x)/1000) * (GRAVITY * 1.0))
  30 #define CONVERT_A_Z(x)              ((float(x)/1000) * (GRAVITY * 1.0))
  31
  32 /* conversion of magnetic data to uT units */
  33 #define CONVERT_M                   (1.0f/6.6f)
  34 #define CONVERT_M_X                 (-CONVERT_M)
  35 #define CONVERT_M_Y                 (-CONVERT_M)
  36 #define CONVERT_M_Z                 (CONVERT_M)
  37
  38 #define CONVERT_GAUSS_TO_MICROTESLA(x)        ( (x) * 100 )
  39
  40 /* conversion of orientation data to degree units */
  41 #define CONVERT_O                   (1.0f/64.0f)
  42 #define CONVERT_O_A                 (CONVERT_O)
  43 #define CONVERT_O_P                 (CONVERT_O)
  44 #define CONVERT_O_R                 (-CONVERT_O)
  45
  46 /*conversion of gyro data to SI units (radian/sec) */
  47 #define CONVERT_GYRO                ((2000.0f/32767.0f)*((float)M_PI / 180.0f))
  48 #define CONVERT_GYRO_X              (-CONVERT_GYRO)
  49 #define CONVERT_GYRO_Y              (-CONVERT_GYRO)
  50 #define CONVERT_GYRO_Z              (CONVERT_GYRO)
  51
  52 #define BIT(x) (1 << (x))
  53
  54 inline unsigned int set_bit_range(int start, int end)
  55 {
  56     int i;
  57     unsigned int value = 0;
  58
  59     for (i = start; i < end; ++i)
  60         value |= BIT(i);
  61     return value;
  62 }
  63
  64 inline float convert_from_vtf_format(int size, int exponent, unsigned int value)
  65 {
  66     int divider=1;
  67     int i;
  68     float sample;
  69     int mul = 1.0;
  70
  71     value = value & set_bit_range(0, size*8);
  72     if (value & BIT(size*8-1)) {
  73         value =  ((1LL << (size*8)) - value);
  74         mul = -1.0;
  75     }
  76     sample = value * 1.0;
  77     if (exponent < 0) {
  78         exponent = abs(exponent);
  79         for (i = 0; i < exponent; ++i) {
  80             divider = divider*10;
  81         }
  82         return mul * sample/divider;
  83     } else {
  84         return mul * sample * pow(10.0, exponent);
  85     }
  86 }
  87
  88 // Platform sensor orientation
  89 #define DEF_ORIENT_ACCEL_X                   -1
  90 #define DEF_ORIENT_ACCEL_Y                   -1
  91 #define DEF_ORIENT_ACCEL_Z                   -1
  92
  93 #define DEF_ORIENT_GYRO_X                   1
  94 #define DEF_ORIENT_GYRO_Y                   1
  95 #define DEF_ORIENT_GYRO_Z                   1
  96
  97 // G to m/s2
  98 #define CONVERT_FROM_VTF16(s,d,x)      (convert_from_vtf_format(s,d,x))
  99 #define CONVERT_A_G_VTF16E14_X(s,d,x)  (DEF_ORIENT_ACCEL_X *\
 100                                         convert_from_vtf_format(s,d,x)*GRAVITY)
 101 #define CONVERT_A_G_VTF16E14_Y(s,d,x)  (DEF_ORIENT_ACCEL_Y *\
 102                                         convert_from_vtf_format(s,d,x)*GRAVITY)
 103 #define CONVERT_A_G_VTF16E14_Z(s,d,x)  (DEF_ORIENT_ACCEL_Z *\
 104                                         convert_from_vtf_format(s,d,x)*GRAVITY)
 105
 106 // Degree/sec to radian/sec
 107 #define CONVERT_G_D_VTF16E14_X(s,d,x)  (DEF_ORIENT_GYRO_X *\
 108                                         convert_from_vtf_format(s,d,x) * \
 109                                         ((float)M_PI/180.0f))
 110 #define CONVERT_G_D_VTF16E14_Y(s,d,x)  (DEF_ORIENT_GYRO_Y *\
 111                                         convert_from_vtf_format(s,d,x) * \
 112                                         ((float)M_PI/180.0f))
 113 #define CONVERT_G_D_VTF16E14_Z(s,d,x)  (DEF_ORIENT_GYRO_Z *\
 114                                         convert_from_vtf_format(s,d,x) * \
 115                                         ((float)M_PI/180.0f))
 116
 117 // Milli gauss to micro tesla
 118 #define CONVERT_M_MG_VTF16E14_X(s,d,x) (convert_from_vtf_format(s,d,x)/10)
 119 #define CONVERT_M_MG_VTF16E14_Y(s,d,x) (convert_from_vtf_format(s,d,x)/10)
 120 #define CONVERT_M_MG_VTF16E14_Z(s,d,x) (convert_from_vtf_format(s,d,x)/10)
 121
 122
 123 /*----------------------------------------------------------------------------*/
 124
 125 static int64_t sample_as_int64(unsigned char* sample, struct datum_info_t* type)
 126 {
 127         uint64_t u64;
 128         int i;
 129         int zeroed_bits = type->storagebits - type->realbits;
 130         uint64_t sign_mask;
 131         uint64_t value_mask;
 132
 133         u64 = 0;
 134
 135         if (type->endianness == 'b')
 136                 for (i=0; i<type->storagebits/8; i++)
 137                         u64 = (u64 << 8) | sample[i];
 138         else
 139                 for (i=type->storagebits/8 - 1; i>=0; i--)
 140                         u64 = (u64 << 8) | sample[i];
 141
 142         u64 = (u64 >> type->shift) & (~0ULL >> zeroed_bits);
 143
 144         if (type->sign == 'u')
 145                 return (int64_t) u64; /* We don't handle unsigned 64 bits int */
 146
 147         /* Signed integer */
 148
 149         switch (type->realbits) {
 150                 case 0 ... 1:
 151                         return 0;
 152
 153                 case 8:
 154                         return (int64_t) (int8_t) u64;
 155
 156                 case 16:
 157                         return (int64_t) (int16_t) u64;
 158
 159                 case 32:
 160                         return (int64_t) (int32_t) u64;
 161
 162                 case 64:
 163                         return (int64_t) u64;
 164
 165                 default:
 166                         sign_mask = 1 << (type->realbits-1);
 167                         value_mask = sign_mask - 1;
 168
 169                         if (u64 & sign_mask)
 170                                 /* Negative value: return 2-complement */
 171                                 return - ((~u64 & value_mask) + 1);
 172                         else
 173                                 return (int64_t) u64; /* Positive value */
 174         }
 175 }
 176
 177
 178 static void reorder_fields(float* data, unsigned char map[MAX_CHANNELS])
 179 {
 180         int i;
 181         float temp[MAX_CHANNELS];
 182
 183         for (i=0; i<MAX_CHANNELS; i++)
 184                 temp[i] = data[map[i]];
 185
 186         for (i=0; i<MAX_CHANNELS; i++)
 187                 data[i] = temp[i];
 188 }
 189
 190
 191 static void denoise (struct sensor_info_t* si, struct sensors_event_t* data,
 192                      int num_fields, int max_samples)
 193 {
 194         /*
 195          * Smooth out incoming data using a moving average over a number of
 196          * samples. We accumulate one second worth of samples, or max_samples,
 197          * depending on which is lower.
 198          */
 199
 200         int i;
 201         float total;
 202         int f;
 203         int sampling_rate = (int) si->sampling_rate;
 204         int history_size;
 205
 206         /* Don't denoise anything if we have less than two samples per second */
 207         if (sampling_rate < 2)
 208                 return;
 209
 210         /* Restrict window size to the min of sampling_rate and max_samples */
 211         if (sampling_rate > max_samples)
 212                 history_size = max_samples;
 213         else
 214                 history_size = sampling_rate;
 215
 216         /* Reset history if we're operating on an incorrect window size */
 217         if (si->history_size != history_size) {
 218                 si->history_size = history_size;
 219                 si->history_entries = 0;
 220                 si->history_index = 0;
 221                 si->history = (float*) realloc(si->history,
 222                                 si->history_size * num_fields * sizeof(float));
 223         }
 224
 225         if (!si->history)
 226                 return; /* Unlikely, but still... */
 227
 228         /* Update initialized samples count */
 229         if (si->history_entries < si->history_size)
 230                 si->history_entries++;
 231
 232         /* Record new sample */
 233         for (f=0; f < num_fields; f++)
 234                 si->history[si->history_index * num_fields + f] = data->data[f];
 235
 236         /* Update our rolling index (next evicted cell) */
 237         si->history_index = (si->history_index + 1) % si->history_size;
 238
 239         /* For now simply compute a mobile mean for each field */
 240         for (f=0; f < num_fields; f++) {
 241                 total = 0;
 242
 243                 for (i=0; i < si->history_entries; i++)
 244                                 total += si->history[i * num_fields + f];
 245
 246                 /* Output filtered data */
 247                 data->data[f] = total / si->history_entries;
 248         }
 249 }
 250
 251
 252 static int finalize_sample_default(int s, struct sensors_event_t* data)
 253 {
 254         int i           = sensor_info[s].catalog_index;
 255         int sensor_type = sensor_catalog[i].type;
 256
 257         /* Swap fields if we have a custom channel ordering on this sensor */
 258         if (sensor_info[s].quirks & QUIRK_FIELD_ORDERING)
 259                 reorder_fields(data->data, sensor_info[s].order);
 260
 261         switch (sensor_type) {
 262                 case SENSOR_TYPE_ACCELEROMETER:
 263                         if (sensor_info[s].quirks & QUIRK_NOISY)
 264                                 denoise(&sensor_info[s], data, 3, 20);
 265                         break;
 266
 267                 case SENSOR_TYPE_MAGNETIC_FIELD:
 268                         calibrate_compass (data, &sensor_info[s], get_timestamp());
 269                         if (sensor_info[s].quirks & QUIRK_NOISY)
 270                                 denoise(&sensor_info[s], data, 3, 100);
 271                         break;
 272
 273                 case SENSOR_TYPE_GYROSCOPE:
 274                 case SENSOR_TYPE_GYROSCOPE_UNCALIBRATED:
 275                         calibrate_gyro(data, &sensor_info[s]);
 276                         if (sensor_info[s].quirks & QUIRK_NOISY)
 277                                 denoise(&sensor_info[s], data, 3, 20);
 278                         break;
 279
 280                 case SENSOR_TYPE_LIGHT:
 281                 case SENSOR_TYPE_AMBIENT_TEMPERATURE:
 282                 case SENSOR_TYPE_TEMPERATURE:
 283                         /* Only keep two decimals for these readings */
 284                         data->data[0] = 0.01 * ((int) (data->data[0] * 100));
 285
 286                         /* ... fall through ... */
 287
 288                 case SENSOR_TYPE_PROXIMITY:
 289                         /*
 290                          * These are on change sensors ; drop the sample if it
 291                          * has the same value as the previously reported one.
 292                          */
 293                         if (data->data[0] == sensor_info[s].prev_val)
 294                                 return 0;
 295
 296                         sensor_info[s].prev_val = data->data[0];
 297                         break;
 298         }
 299
 300         return 1; /* Return sample to Android */
 301 }
 302
 303
 304 static float transform_sample_default(int s, int c, unsigned char* sample_data)
 305 {
 306         struct datum_info_t* sample_type = &sensor_info[s].channel[c].type_info;
 307         int64_t              s64 = sample_as_int64(sample_data, sample_type);
 308         float scale = sensor_info[s].scale ?
 309                         sensor_info[s].scale : sensor_info[s].channel[c].scale;
 310
 311         /* In case correction has been requested using properties, apply it */
 312         scale *= sensor_info[s].channel[c].opt_scale;
 313
 314         /* Apply default scaling rules */
 315         return (sensor_info[s].offset + s64) * scale;
 316 }
 317
 318
 319 static int finalize_sample_ISH(int s, struct sensors_event_t* data)
 320 {
 321         int i           = sensor_info[s].catalog_index;
 322         int sensor_type = sensor_catalog[i].type;
 323         float pitch, roll, yaw;
 324
 325         /* Swap fields if we have a custom channel ordering on this sensor */
 326         if (sensor_info[s].quirks & QUIRK_FIELD_ORDERING)
 327                 reorder_fields(data->data, sensor_info[s].order);
 328
 329         if (sensor_type == SENSOR_TYPE_ORIENTATION) {
 330
 331                 pitch = data->data[0];
 332                 roll = data->data[1];
 333                 yaw = data->data[2];
 334
 335                 data->data[0] = 360.0 - yaw;
 336                 data->data[1] = -pitch;
 337                 data->data[2] = -roll;
 338         }
 339
 340         return 1; /* Return sample to Android */
 341 }
 342
 343
 344 static float transform_sample_ISH(int s, int c, unsigned char* sample_data)
 345 {
 346         struct datum_info_t* sample_type = &sensor_info[s].channel[c].type_info;
 347         int val         = (int) sample_as_int64(sample_data, sample_type);
 348         int i           = sensor_info[s].catalog_index;
 349         int sensor_type = sensor_catalog[i].type;
 350         float correction;
 351         int data_bytes  = (sample_type->realbits)/8;
 352         int exponent    = sensor_info[s].offset;
 353
 354         /* In case correction has been requested using properties, apply it */
 355         correction = sensor_info[s].channel[c].opt_scale;
 356
 357         switch (sensor_type) {
 358                 case SENSOR_TYPE_ACCELEROMETER:
 359                         switch (c) {
 360                                 case 0:
 361                                         return  correction *
 362                                                 CONVERT_A_G_VTF16E14_X(
 363                                                 data_bytes, exponent, val);
 364
 365                                 case 1:
 366                                         return  correction *
 367                                                 CONVERT_A_G_VTF16E14_Y(
 368                                                 data_bytes, exponent, val);
 369
 370                                 case 2:
 371                                         return  correction *
 372                                                 CONVERT_A_G_VTF16E14_Z(
 373                                                 data_bytes, exponent, val);
 374                         }
 375                         break;
 376
 377
 378                 case SENSOR_TYPE_GYROSCOPE:
 379                         switch (c) {
 380                                 case 0:
 381                                         return  correction *
 382                                                 CONVERT_G_D_VTF16E14_X(
 383                                                 data_bytes, exponent, val);
 384
 385                                 case 1:
 386                                         return  correction *
 387                                                 CONVERT_G_D_VTF16E14_Y(
 388                                                 data_bytes, exponent, val);
 389
 390                                 case 2:
 391                                         return  correction *
 392                                                 CONVERT_G_D_VTF16E14_Z(
 393                                                 data_bytes, exponent, val);
 394                         }
 395                         break;
 396
 397                 case SENSOR_TYPE_MAGNETIC_FIELD:
 398                         switch (c) {
 399                                 case 0:
 400                                         return  correction *
 401                                                 CONVERT_M_MG_VTF16E14_X(
 402                                                 data_bytes, exponent, val);
 403
 404                                 case 1:
 405                                         return  correction *
 406                                                 CONVERT_M_MG_VTF16E14_Y(
 407                                                 data_bytes, exponent, val);
 408
 409                                 case 2:
 410                                         return  correction *
 411                                                 CONVERT_M_MG_VTF16E14_Z(
 412                                                 data_bytes, exponent, val);
 413                         }
 414                         break;
 415
 416                 case SENSOR_TYPE_LIGHT:
 417                                 return (float) val;
 418
 419                 case SENSOR_TYPE_ORIENTATION:
 420                         return  correction * convert_from_vtf_format(
 421                                                 data_bytes, exponent, val);
 422
 423                 case SENSOR_TYPE_ROTATION_VECTOR:
 424                         return  correction * convert_from_vtf_format(
 425                                                 data_bytes, exponent, val);
 426         }
 427
 428         return 0;
 429 }
 430
 431
 432 void select_transform (int s)
 433 {
 434         char prop_name[PROP_NAME_MAX];
 435         char prop_val[PROP_VALUE_MAX];
 436         int i                   = sensor_info[s].catalog_index;
 437         const char *prefix      = sensor_catalog[i].tag;
 438
 439         sprintf(prop_name, PROP_BASE, prefix, "transform");
 440
 441         if (property_get(prop_name, prop_val, "")) {
 442                 if (!strcmp(prop_val, "ISH")) {
 443                         ALOGI(  "Using Intel Sensor Hub semantics on %s\n",
 444                                 sensor_info[s].friendly_name);
 445
 446                         sensor_info[s].ops.transform = transform_sample_ISH;
 447                         sensor_info[s].ops.finalize = finalize_sample_ISH;
 448                         return;
 449                 }
 450         }
 451
 452         sensor_info[s].ops.transform = transform_sample_default;
 453         sensor_info[s].ops.finalize = finalize_sample_default;
 454 }
 455
 456
 457 float acquire_immediate_value(int s, int c)
 458 {
 459         char sysfs_path[PATH_MAX];
 460         float val;
 461         int ret;
 462         int dev_num = sensor_info[s].dev_num;
 463         int i = sensor_info[s].catalog_index;
 464         const char* raw_path = sensor_catalog[i].channel[c].raw_path;
 465         const char* input_path = sensor_catalog[i].channel[c].input_path;
 466         float scale = sensor_info[s].scale ?
 467                         sensor_info[s].scale : sensor_info[s].channel[c].scale;
 468         float offset = sensor_info[s].offset;
 469         int sensor_type = sensor_catalog[i].type;
 470         float correction;
 471
 472         /* In case correction has been requested using properties, apply it */
 473         correction = sensor_info[s].channel[c].opt_scale;
 474
 475         /* Acquire a sample value for sensor s / channel c through sysfs */
 476
 477         if (input_path[0]) {
 478                 sprintf(sysfs_path, BASE_PATH "%s", dev_num, input_path);
 479                 ret = sysfs_read_float(sysfs_path, &val);
 480
 481                 if (!ret) {
 482                         return val * correction;
 483                 }
 484         };
 485
 486         if (!raw_path[0])
 487                 return 0;
 488
 489         sprintf(sysfs_path, BASE_PATH "%s", dev_num, raw_path);
 490         ret = sysfs_read_float(sysfs_path, &val);
 491
 492         if (ret == -1)
 493                 return 0;
 494
 495         /*
 496         There is no transform ops defined yet for Raw sysfs values
 497         Use this function to perform transformation as well.
 498         */
 499         if (sensor_type == SENSOR_TYPE_MAGNETIC_FIELD)
 500                 return  CONVERT_GAUSS_TO_MICROTESLA ((val + offset) * scale) *
 501                         correction;
 502
 503         return (val + offset) * scale * correction;
 504 }