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)
 193 {
 194         int i;
 195         float total;
 196         int f;
 197         int sampling_rate = (int) si->sampling_rate;
 198
 199         /* We're recording 1s worth of samples ; need suitable sampling rate */
 200         if (sampling_rate < 1)
 201                 return;
 202
 203         /* Reset history if a new sampling rate is detected */
 204         if (si->history_size != sampling_rate) {
 205                 si->history_size = sampling_rate;
 206                 si->history_entries = 0;
 207                 si->history_index = 0;
 208                 si->history = (float*) realloc(si->history,
 209                                 si->history_size * num_fields * sizeof(float));
 210         }
 211
 212         if (!si->history)
 213                 return; /* Unlikely, but still... */
 214
 215         /* Populate beginning of array as we go */
 216         if (si->history_entries < si->history_size) {
 217                 for (f=0; f<num_fields; f++)
 218                         si->history[si->history_entries * num_fields + f] =
 219                                 data->data[f];
 220
 221                 si->history_entries++;
 222         }
 223
 224         /* Once we get enough data, start filtering */
 225         if (si->history_entries == si->history_size) {
 226
 227                 /* For now simply compute a mobile mean */
 228                 for (f=0; f<num_fields; f++) {
 229                         total = 0;
 230
 231                         for (i=0; i<si->history_size; i++)
 232                                 total += si->history[i * num_fields + f];
 233
 234                         si->history[si->history_index * num_fields + f] =
 235                                 data->data[f];
 236
 237                         /* Output filtered data */
 238                         data->data[f] = total / si->history_size;
 239                 }
 240
 241                 /* Update our rolling index (next evicted cell) */
 242                 si->history_index = (si->history_index + 1) % si->history_size;
 243         }
 244 }
 245
 246
 247 static int finalize_sample_default(int s, struct sensors_event_t* data)
 248 {
 249         int i           = sensor_info[s].catalog_index;
 250         int sensor_type = sensor_catalog[i].type;
 251
 252         /* Swap fields if we have a custom channel ordering on this sensor */
 253         if (sensor_info[s].quirks & QUIRK_FIELD_ORDERING)
 254                 reorder_fields(data->data, sensor_info[s].order);
 255
 256         switch (sensor_type) {
 257                 case SENSOR_TYPE_ACCELEROMETER:
 258                         break;
 259
 260                 case SENSOR_TYPE_MAGNETIC_FIELD:
 261                         calibrate_compass (data, &sensor_info[s], get_timestamp());
 262                         if (sensor_info[s].quirks & QUIRK_NOISY)
 263                                 denoise(&sensor_info[s], data, 3);
 264                         break;
 265
 266                 case SENSOR_TYPE_GYROSCOPE:
 267                 case SENSOR_TYPE_GYROSCOPE_UNCALIBRATED:
 268                         calibrate_gyro(data, &sensor_info[s]);
 269                         break;
 270
 271                 case SENSOR_TYPE_LIGHT:
 272                 case SENSOR_TYPE_AMBIENT_TEMPERATURE:
 273                 case SENSOR_TYPE_TEMPERATURE:
 274                         /* Only keep two decimals for these readings */
 275                         data->data[0] = 0.01 * ((int) (data->data[0] * 100));
 276
 277                         /* ... fall through ... */
 278
 279                 case SENSOR_TYPE_PROXIMITY:
 280                         /*
 281                          * These are on change sensors ; drop the sample if it
 282                          * has the same value as the previously reported one.
 283                          */
 284                         if (data->data[0] == sensor_info[s].prev_val)
 285                                 return 0;
 286
 287                         sensor_info[s].prev_val = data->data[0];
 288                         break;
 289         }
 290
 291         return 1; /* Return sample to Android */
 292 }
 293
 294
 295 static float transform_sample_default(int s, int c, unsigned char* sample_data)
 296 {
 297         struct datum_info_t* sample_type = &sensor_info[s].channel[c].type_info;
 298         int64_t              s64 = sample_as_int64(sample_data, sample_type);
 299         float scale = sensor_info[s].scale ?
 300                         sensor_info[s].scale : sensor_info[s].channel[c].scale;
 301
 302         /* In case correction has been requested using properties, apply it */
 303         scale *= sensor_info[s].channel[c].opt_scale;
 304
 305         /* Apply default scaling rules */
 306         return (sensor_info[s].offset + s64) * scale;
 307 }
 308
 309
 310 static int finalize_sample_ISH(int s, struct sensors_event_t* data)
 311 {
 312         int i           = sensor_info[s].catalog_index;
 313         int sensor_type = sensor_catalog[i].type;
 314         float pitch, roll, yaw;
 315
 316         /* Swap fields if we have a custom channel ordering on this sensor */
 317         if (sensor_info[s].quirks & QUIRK_FIELD_ORDERING)
 318                 reorder_fields(data->data, sensor_info[s].order);
 319
 320         if (sensor_type == SENSOR_TYPE_ORIENTATION) {
 321
 322                 pitch = data->data[0];
 323                 roll = data->data[1];
 324                 yaw = data->data[2];
 325
 326                 data->data[0] = 360.0 - yaw;
 327                 data->data[1] = -pitch;
 328                 data->data[2] = -roll;
 329         }
 330
 331         return 1; /* Return sample to Android */
 332 }
 333
 334
 335 static float transform_sample_ISH(int s, int c, unsigned char* sample_data)
 336 {
 337         struct datum_info_t* sample_type = &sensor_info[s].channel[c].type_info;
 338         int val         = (int) sample_as_int64(sample_data, sample_type);
 339         int i           = sensor_info[s].catalog_index;
 340         int sensor_type = sensor_catalog[i].type;
 341         float correction;
 342         int data_bytes  = (sample_type->realbits)/8;
 343         int exponent    = sensor_info[s].offset;
 344
 345         /* In case correction has been requested using properties, apply it */
 346         correction = sensor_info[s].channel[c].opt_scale;
 347
 348         switch (sensor_type) {
 349                 case SENSOR_TYPE_ACCELEROMETER:
 350                         switch (c) {
 351                                 case 0:
 352                                         return  correction *
 353                                                 CONVERT_A_G_VTF16E14_X(
 354                                                 data_bytes, exponent, val);
 355
 356                                 case 1:
 357                                         return  correction *
 358                                                 CONVERT_A_G_VTF16E14_Y(
 359                                                 data_bytes, exponent, val);
 360
 361                                 case 2:
 362                                         return  correction *
 363                                                 CONVERT_A_G_VTF16E14_Z(
 364                                                 data_bytes, exponent, val);
 365                         }
 366                         break;
 367
 368
 369                 case SENSOR_TYPE_GYROSCOPE:
 370                         switch (c) {
 371                                 case 0:
 372                                         return  correction *
 373                                                 CONVERT_G_D_VTF16E14_X(
 374                                                 data_bytes, exponent, val);
 375
 376                                 case 1:
 377                                         return  correction *
 378                                                 CONVERT_G_D_VTF16E14_Y(
 379                                                 data_bytes, exponent, val);
 380
 381                                 case 2:
 382                                         return  correction *
 383                                                 CONVERT_G_D_VTF16E14_Z(
 384                                                 data_bytes, exponent, val);
 385                         }
 386                         break;
 387
 388                 case SENSOR_TYPE_MAGNETIC_FIELD:
 389                         switch (c) {
 390                                 case 0:
 391                                         return  correction *
 392                                                 CONVERT_M_MG_VTF16E14_X(
 393                                                 data_bytes, exponent, val);
 394
 395                                 case 1:
 396                                         return  correction *
 397                                                 CONVERT_M_MG_VTF16E14_Y(
 398                                                 data_bytes, exponent, val);
 399
 400                                 case 2:
 401                                         return  correction *
 402                                                 CONVERT_M_MG_VTF16E14_Z(
 403                                                 data_bytes, exponent, val);
 404                         }
 405                         break;
 406
 407                 case SENSOR_TYPE_LIGHT:
 408                                 return (float) val;
 409
 410                 case SENSOR_TYPE_ORIENTATION:
 411                         return  correction * convert_from_vtf_format(
 412                                                 data_bytes, exponent, val);
 413
 414                 case SENSOR_TYPE_ROTATION_VECTOR:
 415                         return  correction * convert_from_vtf_format(
 416                                                 data_bytes, exponent, val);
 417         }
 418
 419         return 0;
 420 }
 421
 422
 423 void select_transform (int s)
 424 {
 425         char prop_name[PROP_NAME_MAX];
 426         char prop_val[PROP_VALUE_MAX];
 427         int i                   = sensor_info[s].catalog_index;
 428         const char *prefix      = sensor_catalog[i].tag;
 429
 430         sprintf(prop_name, PROP_BASE, prefix, "transform");
 431
 432         if (property_get(prop_name, prop_val, "")) {
 433                 if (!strcmp(prop_val, "ISH")) {
 434                         ALOGI(  "Using Intel Sensor Hub semantics on %s\n",
 435                                 sensor_info[s].friendly_name);
 436
 437                         sensor_info[s].ops.transform = transform_sample_ISH;
 438                         sensor_info[s].ops.finalize = finalize_sample_ISH;
 439                         return;
 440                 }
 441         }
 442
 443         sensor_info[s].ops.transform = transform_sample_default;
 444         sensor_info[s].ops.finalize = finalize_sample_default;
 445 }
 446
 447
 448 float acquire_immediate_value(int s, int c)
 449 {
 450         char sysfs_path[PATH_MAX];
 451         float val;
 452         int ret;
 453         int dev_num = sensor_info[s].dev_num;
 454         int i = sensor_info[s].catalog_index;
 455         const char* raw_path = sensor_catalog[i].channel[c].raw_path;
 456         const char* input_path = sensor_catalog[i].channel[c].input_path;
 457         float scale = sensor_info[s].scale ?
 458                         sensor_info[s].scale : sensor_info[s].channel[c].scale;
 459         float offset = sensor_info[s].offset;
 460         int sensor_type = sensor_catalog[i].type;
 461         float correction;
 462
 463         /* In case correction has been requested using properties, apply it */
 464         correction = sensor_info[s].channel[c].opt_scale;
 465
 466         /* Acquire a sample value for sensor s / channel c through sysfs */
 467
 468         if (input_path[0]) {
 469                 sprintf(sysfs_path, BASE_PATH "%s", dev_num, input_path);
 470                 ret = sysfs_read_float(sysfs_path, &val);
 471
 472                 if (!ret) {
 473                         return val * correction;
 474                 }
 475         };
 476
 477         if (!raw_path[0])
 478                 return 0;
 479
 480         sprintf(sysfs_path, BASE_PATH "%s", dev_num, raw_path);
 481         ret = sysfs_read_float(sysfs_path, &val);
 482
 483         if (ret == -1)
 484                 return 0;
 485
 486         /*
 487         There is no transform ops defined yet for Raw sysfs values
 488         Use this function to perform transformation as well.
 489         */
 490         if (sensor_type == SENSOR_TYPE_MAGNETIC_FIELD)
 491                 return  CONVERT_GAUSS_TO_MICROTESLA ((val + offset) * scale) *
 492                         correction;
 493
 494         return (val + offset) * scale * correction;
 495 }