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 "common.h"
  11 #include "transform.h"
  12 #include "utils.h"
  13 #include "calibration.h"
  14
  15 /*----------------------------------------------------------------------------*/
  16
  17 /* Macros related to Intel Sensor Hub */
  18
  19 #define GRAVITY 9.80665f
  20
  21 /* 720 LSG = 1G */
  22 #define LSG                         (1024.0f)
  23 #define NUMOFACCDATA                (8.0f)
  24
  25 /* conversion of acceleration data to SI units (m/s^2) */
  26 #define CONVERT_A                   (GRAVITY_EARTH / LSG / NUMOFACCDATA)
  27 #define CONVERT_A_X(x)              ((float(x)/1000) * (GRAVITY * -1.0))
  28 #define CONVERT_A_Y(x)              ((float(x)/1000) * (GRAVITY * 1.0))
  29 #define CONVERT_A_Z(x)              ((float(x)/1000) * (GRAVITY * 1.0))
  30
  31 /* conversion of magnetic data to uT units */
  32 #define CONVERT_M                   (1.0f/6.6f)
  33 #define CONVERT_M_X                 (-CONVERT_M)
  34 #define CONVERT_M_Y                 (-CONVERT_M)
  35 #define CONVERT_M_Z                 (CONVERT_M)
  36
  37 #define CONVERT_GAUSS_TO_MICROTESLA(x)        ( (x) * 100 )
  38
  39 /* conversion of orientation data to degree units */
  40 #define CONVERT_O                   (1.0f/64.0f)
  41 #define CONVERT_O_A                 (CONVERT_O)
  42 #define CONVERT_O_P                 (CONVERT_O)
  43 #define CONVERT_O_R                 (-CONVERT_O)
  44
  45 /*conversion of gyro data to SI units (radian/sec) */
  46 #define CONVERT_GYRO                ((2000.0f/32767.0f)*((float)M_PI / 180.0f))
  47 #define CONVERT_GYRO_X              (-CONVERT_GYRO)
  48 #define CONVERT_GYRO_Y              (-CONVERT_GYRO)
  49 #define CONVERT_GYRO_Z              (CONVERT_GYRO)
  50
  51 #define BIT(x) (1 << (x))
  52
  53 inline unsigned int set_bit_range(int start, int end)
  54 {
  55     int i;
  56     unsigned int value = 0;
  57
  58     for (i = start; i < end; ++i)
  59         value |= BIT(i);
  60     return value;
  61 }
  62
  63 inline float convert_from_vtf_format(int size, int exponent, unsigned int value)
  64 {
  65     int divider=1;
  66     int i;
  67     float sample;
  68     int mul = 1.0;
  69
  70     value = value & set_bit_range(0, size*8);
  71     if (value & BIT(size*8-1)) {
  72         value =  ((1LL << (size*8)) - value);
  73         mul = -1.0;
  74     }
  75     sample = value * 1.0;
  76     if (exponent < 0) {
  77         exponent = abs(exponent);
  78         for (i = 0; i < exponent; ++i) {
  79             divider = divider*10;
  80         }
  81         return mul * sample/divider;
  82     } else {
  83         return mul * sample * pow(10.0, exponent);
  84     }
  85 }
  86
  87 // Platform sensor orientation
  88 #define DEF_ORIENT_ACCEL_X                   -1
  89 #define DEF_ORIENT_ACCEL_Y                   -1
  90 #define DEF_ORIENT_ACCEL_Z                   -1
  91
  92 #define DEF_ORIENT_GYRO_X                   1
  93 #define DEF_ORIENT_GYRO_Y                   1
  94 #define DEF_ORIENT_GYRO_Z                   1
  95
  96 // G to m/s2
  97 #define CONVERT_FROM_VTF16(s,d,x)      (convert_from_vtf_format(s,d,x))
  98 #define CONVERT_A_G_VTF16E14_X(s,d,x)  (DEF_ORIENT_ACCEL_X *\
  99                                         convert_from_vtf_format(s,d,x)*GRAVITY)
 100 #define CONVERT_A_G_VTF16E14_Y(s,d,x)  (DEF_ORIENT_ACCEL_Y *\
 101                                         convert_from_vtf_format(s,d,x)*GRAVITY)
 102 #define CONVERT_A_G_VTF16E14_Z(s,d,x)  (DEF_ORIENT_ACCEL_Z *\
 103                                         convert_from_vtf_format(s,d,x)*GRAVITY)
 104
 105 // Degree/sec to radian/sec
 106 #define CONVERT_G_D_VTF16E14_X(s,d,x)  (DEF_ORIENT_GYRO_X *\
 107                                         convert_from_vtf_format(s,d,x) * \
 108                                         ((float)M_PI/180.0f))
 109 #define CONVERT_G_D_VTF16E14_Y(s,d,x)  (DEF_ORIENT_GYRO_Y *\
 110                                         convert_from_vtf_format(s,d,x) * \
 111                                         ((float)M_PI/180.0f))
 112 #define CONVERT_G_D_VTF16E14_Z(s,d,x)  (DEF_ORIENT_GYRO_Z *\
 113                                         convert_from_vtf_format(s,d,x) * \
 114                                         ((float)M_PI/180.0f))
 115
 116 // Milli gauss to micro tesla
 117 #define CONVERT_M_MG_VTF16E14_X(s,d,x) (convert_from_vtf_format(s,d,x)/10)
 118 #define CONVERT_M_MG_VTF16E14_Y(s,d,x) (convert_from_vtf_format(s,d,x)/10)
 119 #define CONVERT_M_MG_VTF16E14_Z(s,d,x) (convert_from_vtf_format(s,d,x)/10)
 120
 121
 122 /*----------------------------------------------------------------------------*/
 123
 124 static int64_t sample_as_int64(unsigned char* sample, struct datum_info_t* type)
 125 {
 126         uint64_t u64;
 127         int i;
 128         int zeroed_bits = type->storagebits - type->realbits;
 129         uint64_t sign_mask;
 130         uint64_t value_mask;
 131
 132         u64 = 0;
 133
 134         if (type->endianness == 'b')
 135                 for (i=0; i<type->storagebits/8; i++)
 136                         u64 = (u64 << 8) | sample[i];
 137         else
 138                 for (i=type->storagebits/8 - 1; i>=0; i--)
 139                         u64 = (u64 << 8) | sample[i];
 140
 141         u64 = (u64 >> type->shift) & (~0ULL >> zeroed_bits);
 142
 143         if (type->sign == 'u')
 144                 return (int64_t) u64; /* We don't handle unsigned 64 bits int */
 145
 146         /* Signed integer */
 147
 148         switch (type->realbits) {
 149                 case 0 ... 1:
 150                         return 0;
 151
 152                 case 8:
 153                         return (int64_t) (int8_t) u64;
 154
 155                 case 16:
 156                         return (int64_t) (int16_t) u64;
 157
 158                 case 32:
 159                         return (int64_t) (int32_t) u64;
 160
 161                 case 64:
 162                         return (int64_t) u64;
 163
 164                 default:
 165                         sign_mask = 1 << (type->realbits-1);
 166                         value_mask = sign_mask - 1;
 167
 168                         if (u64 & sign_mask)
 169                                 /* Negative value: return 2-complement */
 170                                 return - ((~u64 & value_mask) + 1);
 171                         else
 172                                 return (int64_t) u64; /* Positive value */
 173         }
 174 }
 175
 176
 177 static void reorder_fields(float* data, unsigned char map[MAX_CHANNELS])
 178 {
 179         int i;
 180         float temp[MAX_CHANNELS];
 181
 182         for (i=0; i<MAX_CHANNELS; i++)
 183                 temp[i] = data[map[i]];
 184
 185         for (i=0; i<MAX_CHANNELS; i++)
 186                 data[i] = temp[i];
 187 }
 188
 189
 190 static int finalize_sample_default(int s, struct sensors_event_t* data)
 191 {
 192         int i           = sensor_info[s].catalog_index;
 193         int sensor_type = sensor_catalog[i].type;
 194
 195         /* Swap fields if we have a custom channel ordering on this sensor */
 196         if (sensor_info[s].flags & FLAG_FIELD_ORDERING)
 197                 reorder_fields(data->data, sensor_info[s].order);
 198
 199         switch (sensor_type) {
 200                 case SENSOR_TYPE_ACCELEROMETER:
 201                         break;
 202
 203                 case SENSOR_TYPE_MAGNETIC_FIELD:
 204                         calibrate_compass (data, &sensor_info[s], get_timestamp());
 205                         break;
 206
 207                 case SENSOR_TYPE_GYROSCOPE:
 208                 case SENSOR_TYPE_GYROSCOPE_UNCALIBRATED:
 209                         calibrate_gyro(data, &sensor_info[s]);
 210                         break;
 211
 212                 case SENSOR_TYPE_LIGHT:
 213                 case SENSOR_TYPE_AMBIENT_TEMPERATURE:
 214                 case SENSOR_TYPE_TEMPERATURE:
 215                         /* Only keep two decimals for these readings */
 216                         data->data[0] = 0.01 * ((int) (data->data[0] * 100));
 217
 218                         /*
 219                          * These are on change sensors ; drop the sample if it
 220                          * has the same value as the previously reported one.
 221                          */
 222                         if (data->data[0] == sensor_info[s].prev_val)
 223                                 return 0;
 224
 225                         sensor_info[s].prev_val = data->data[0];
 226                         break;
 227         }
 228
 229         return 1; /* Return sample to Android */
 230 }
 231
 232
 233 static float transform_sample_default(int s, int c, unsigned char* sample_data)
 234 {
 235         struct datum_info_t* sample_type = &sensor_info[s].channel[c].type_info;
 236         int64_t              s64 = sample_as_int64(sample_data, sample_type);
 237         float scale = sensor_info[s].scale ?
 238                         sensor_info[s].scale : sensor_info[s].channel[c].scale;
 239
 240         /* In case correction has been requested using properties, apply it */
 241         scale *= sensor_info[s].channel[c].opt_scale;
 242
 243         /* Apply default scaling rules */
 244         return (sensor_info[s].offset + s64) * scale;
 245 }
 246
 247
 248 static int finalize_sample_ISH(int s, struct sensors_event_t* data)
 249 {
 250         int i           = sensor_info[s].catalog_index;
 251         int sensor_type = sensor_catalog[i].type;
 252         float pitch, roll, yaw;
 253
 254         /* Swap fields if we have a custom channel ordering on this sensor */
 255         if (sensor_info[s].flags & FLAG_FIELD_ORDERING)
 256                 reorder_fields(data->data, sensor_info[s].order);
 257
 258         if (sensor_type == SENSOR_TYPE_ORIENTATION) {
 259
 260                 pitch = data->data[0];
 261                 roll = data->data[1];
 262                 yaw = data->data[2];
 263
 264                 data->data[0] = 360.0 - yaw;
 265                 data->data[1] = -pitch;
 266                 data->data[2] = -roll;
 267         }
 268
 269         return 1; /* Return sample to Android */
 270 }
 271
 272
 273 static float transform_sample_ISH(int s, int c, unsigned char* sample_data)
 274 {
 275         struct datum_info_t* sample_type = &sensor_info[s].channel[c].type_info;
 276         int val         = (int) sample_as_int64(sample_data, sample_type);
 277         int i           = sensor_info[s].catalog_index;
 278         int sensor_type = sensor_catalog[i].type;
 279         float correction;
 280         int data_bytes  = (sample_type->realbits)/8;
 281         int exponent    = sensor_info[s].offset;
 282
 283         /* In case correction has been requested using properties, apply it */
 284         correction = sensor_info[s].channel[c].opt_scale;
 285
 286         switch (sensor_type) {
 287                 case SENSOR_TYPE_ACCELEROMETER:
 288                         switch (c) {
 289                                 case 0:
 290                                         return  correction *
 291                                                 CONVERT_A_G_VTF16E14_X(
 292                                                 data_bytes, exponent, val);
 293
 294                                 case 1:
 295                                         return  correction *
 296                                                 CONVERT_A_G_VTF16E14_Y(
 297                                                 data_bytes, exponent, val);
 298
 299                                 case 2:
 300                                         return  correction *
 301                                                 CONVERT_A_G_VTF16E14_Z(
 302                                                 data_bytes, exponent, val);
 303                         }
 304                         break;
 305
 306
 307                 case SENSOR_TYPE_GYROSCOPE:
 308                         switch (c) {
 309                                 case 0:
 310                                         return  correction *
 311                                                 CONVERT_G_D_VTF16E14_X(
 312                                                 data_bytes, exponent, val);
 313
 314                                 case 1:
 315                                         return  correction *
 316                                                 CONVERT_G_D_VTF16E14_Y(
 317                                                 data_bytes, exponent, val);
 318
 319                                 case 2:
 320                                         return  correction *
 321                                                 CONVERT_G_D_VTF16E14_Z(
 322                                                 data_bytes, exponent, val);
 323                         }
 324                         break;
 325
 326                 case SENSOR_TYPE_MAGNETIC_FIELD:
 327                         switch (c) {
 328                                 case 0:
 329                                         return  correction *
 330                                                 CONVERT_M_MG_VTF16E14_X(
 331                                                 data_bytes, exponent, val);
 332
 333                                 case 1:
 334                                         return  correction *
 335                                                 CONVERT_M_MG_VTF16E14_Y(
 336                                                 data_bytes, exponent, val);
 337
 338                                 case 2:
 339                                         return  correction *
 340                                                 CONVERT_M_MG_VTF16E14_Z(
 341                                                 data_bytes, exponent, val);
 342                         }
 343                         break;
 344
 345                 case SENSOR_TYPE_LIGHT:
 346                                 return (float) val;
 347
 348                 case SENSOR_TYPE_ORIENTATION:
 349                         return  correction * convert_from_vtf_format(
 350                                                 data_bytes, exponent, val);
 351
 352                 case SENSOR_TYPE_ROTATION_VECTOR:
 353                         return  correction * convert_from_vtf_format(
 354                                                 data_bytes, exponent, val);
 355         }
 356
 357         return 0;
 358 }
 359
 360
 361 void select_transform (int s)
 362 {
 363         char prop_name[PROP_NAME_MAX];
 364         char prop_val[PROP_VALUE_MAX];
 365         int i                   = sensor_info[s].catalog_index;
 366         const char *prefix      = sensor_catalog[i].tag;
 367
 368         sprintf(prop_name, PROP_BASE, prefix, "transform");
 369
 370         if (property_get(prop_name, prop_val, "")) {
 371                 if (!strcmp(prop_val, "ISH")) {
 372                         ALOGI(  "Using Intel Sensor Hub semantics on %s\n",
 373                                 sensor_info[s].friendly_name);
 374
 375                         sensor_info[s].ops.transform = transform_sample_ISH;
 376                         sensor_info[s].ops.finalize = finalize_sample_ISH;
 377                         return;
 378                 }
 379         }
 380
 381         sensor_info[s].ops.transform = transform_sample_default;
 382         sensor_info[s].ops.finalize = finalize_sample_default;
 383 }
 384
 385
 386 float acquire_immediate_value(int s, int c)
 387 {
 388         char sysfs_path[PATH_MAX];
 389         float val;
 390         int ret;
 391         int dev_num = sensor_info[s].dev_num;
 392         int i = sensor_info[s].catalog_index;
 393         const char* raw_path = sensor_catalog[i].channel[c].raw_path;
 394         const char* input_path = sensor_catalog[i].channel[c].input_path;
 395         float scale = sensor_info[s].scale ?
 396                         sensor_info[s].scale : sensor_info[s].channel[c].scale;
 397         float offset = sensor_info[s].offset;
 398         int sensor_type = sensor_catalog[i].type;
 399         float correction;
 400
 401         /* In case correction has been requested using properties, apply it */
 402         correction = sensor_info[s].channel[c].opt_scale;
 403
 404         /* Acquire a sample value for sensor s / channel c through sysfs */
 405
 406         if (input_path[0]) {
 407                 sprintf(sysfs_path, BASE_PATH "%s", dev_num, input_path);
 408                 ret = sysfs_read_float(sysfs_path, &val);
 409
 410                 if (!ret) {
 411                         return val * correction;
 412                 }
 413         };
 414
 415         if (!raw_path[0])
 416                 return 0;
 417
 418         sprintf(sysfs_path, BASE_PATH "%s", dev_num, raw_path);
 419         ret = sysfs_read_float(sysfs_path, &val);
 420
 421         if (ret == -1)
 422                 return 0;
 423
 424         /*
 425         There is no transform ops defined yet for Raw sysfs values
 426         Use this function to perform transformation as well.
 427         */
 428         if (sensor_type == SENSOR_TYPE_MAGNETIC_FIELD)
 429                 return  CONVERT_GAUSS_TO_MICROTESLA ((val + offset) * scale) *
 430                         correction;
 431
 432         return (val + offset) * scale * correction;
 433 }