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         uint16_t u16;
 127         uint32_t u32;
 128         uint64_t u64;
 129         int i;
 130         int zeroed_bits = type->storagebits - type->realbits;
 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         switch (type->realbits) {
 147                 case 8:
 148                         return (int64_t) (int8_t) u64;
 149
 150                 case 12:
 151                         return (int64_t)  (u64 >>  11) ?
 152                                         (((int64_t)-1) ^ 0xfff) | u64 : u64;
 153
 154                 case 16:
 155                         return (int64_t) (int16_t) u64;
 156
 157                 case 32:
 158                         return (int64_t) (int32_t) u64;
 159
 160                 case 64:
 161                         return (int64_t) u64;
 162         }
 163
 164         ALOGE("Unhandled sample storage size\n");
 165         return 0;
 166 }
 167
 168
 169 static void finalize_sample_default(int s, struct sensors_event_t* data)
 170 {
 171         int i           = sensor_info[s].catalog_index;
 172         int sensor_type = sensor_catalog[i].type;
 173         float x, y, z;
 174
 175         switch (sensor_type) {
 176                 case SENSOR_TYPE_ACCELEROMETER:
 177                         /*
 178                          * Invert x and z axes orientation from SI units - see
 179                          * /hardware/libhardware/include/hardware/sensors.h
 180                          * for a discussion of what Android expects
 181                          */
 182                         x = -data->data[0];
 183                         y = data->data[1];
 184                         z = -data->data[2];
 185
 186                         data->data[0] = x;
 187                         data->data[1] = y;
 188                         data->data[2] = z;
 189                         break;
 190
 191                 case SENSOR_TYPE_MAGNETIC_FIELD:
 192                         x = -data->data[0];
 193                         y = data->data[1];
 194                         z = -data->data[2];
 195
 196                         data->data[0] = x;
 197                         data->data[1] = y;
 198                         data->data[2] = z;
 199
 200                         /* Calibrate compass */
 201                         calibrate_compass (data, get_timestamp());
 202                         break;
 203
 204                 case SENSOR_TYPE_GYROSCOPE:
 205                         x = -data->data[0];
 206                         y = data->data[1];
 207                         z = -data->data[2];
 208
 209                         /* Limit drift */
 210                         if (fabs(x) < 0.1 && fabs(y) < 0.1 && fabs(z) < 0.1)
 211                                 x = y = z = 0;
 212
 213                         data->data[0] = x;
 214                         data->data[1] = y;
 215                         data->data[2] = z;
 216                         break;
 217
 218                 case SENSOR_TYPE_AMBIENT_TEMPERATURE:
 219                 case SENSOR_TYPE_TEMPERATURE:
 220                         /* Only keep two decimals for temperature readings */
 221                         data->data[0] = 0.01 * ((int) (data->data[0] * 100));
 222                         break;
 223
 224         }
 225 }
 226
 227
 228 static float transform_sample_default(int s, int c, unsigned char* sample_data)
 229 {
 230         struct datum_info_t* sample_type = &sensor_info[s].channel[c].type_info;
 231         int64_t              s64 = sample_as_int64(sample_data, sample_type);
 232         float scale = sensor_info[s].scale ?
 233                         sensor_info[s].scale : sensor_info[s].channel[c].scale;
 234
 235         /* In case correction has been requested using properties, apply it */
 236         scale *= sensor_info[s].channel[c].opt_scale;
 237
 238         /* Apply default scaling rules */
 239         return (sensor_info[s].offset + s64) * scale;
 240 }
 241
 242
 243 static void finalize_sample_ISH(int s, struct sensors_event_t* data)
 244 {
 245         int i           = sensor_info[s].catalog_index;
 246         int sensor_type = sensor_catalog[i].type;
 247         float pitch, roll, yaw;
 248
 249         if (sensor_type == SENSOR_TYPE_ORIENTATION) {
 250
 251                 pitch = data->data[0];
 252                 roll = data->data[1];
 253                 yaw = data->data[2];
 254
 255                 data->data[0] = 360.0 - yaw;
 256                 data->data[1] = -pitch;
 257                 data->data[2] = -roll;
 258         }
 259 }
 260
 261
 262 static float transform_sample_ISH(int s, int c, unsigned char* sample_data)
 263 {
 264         struct datum_info_t* sample_type = &sensor_info[s].channel[c].type_info;
 265         int val         = (int) sample_as_int64(sample_data, sample_type);
 266         int i           = sensor_info[s].catalog_index;
 267         int sensor_type = sensor_catalog[i].type;
 268         float correction;
 269         int data_bytes  = (sample_type->realbits)/8;
 270         int exponent    = sensor_info[s].offset;
 271
 272         /* In case correction has been requested using properties, apply it */
 273         correction = sensor_info[s].channel[c].opt_scale;
 274
 275         switch (sensor_type) {
 276                 case SENSOR_TYPE_ACCELEROMETER:
 277                         switch (c) {
 278                                 case 0:
 279                                         return  correction *
 280                                                 CONVERT_A_G_VTF16E14_X(
 281                                                 data_bytes, exponent, val);
 282
 283                                 case 1:
 284                                         return  correction *
 285                                                 CONVERT_A_G_VTF16E14_Y(
 286                                                 data_bytes, exponent, val);
 287
 288                                 case 2:
 289                                         return  correction *
 290                                                 CONVERT_A_G_VTF16E14_Z(
 291                                                 data_bytes, exponent, val);
 292                         }
 293                         break;
 294
 295
 296                 case SENSOR_TYPE_GYROSCOPE:
 297                         switch (c) {
 298                                 case 0:
 299                                         return  correction *
 300                                                 CONVERT_G_D_VTF16E14_X(
 301                                                 data_bytes, exponent, val);
 302
 303                                 case 1:
 304                                         return  correction *
 305                                                 CONVERT_G_D_VTF16E14_Y(
 306                                                 data_bytes, exponent, val);
 307
 308                                 case 2:
 309                                         return  correction *
 310                                                 CONVERT_G_D_VTF16E14_Z(
 311                                                 data_bytes, exponent, val);
 312                         }
 313                         break;
 314
 315                 case SENSOR_TYPE_MAGNETIC_FIELD:
 316                         switch (c) {
 317                                 case 0:
 318                                         return  correction *
 319                                                 CONVERT_M_MG_VTF16E14_X(
 320                                                 data_bytes, exponent, val);
 321
 322                                 case 1:
 323                                         return  correction *
 324                                                 CONVERT_M_MG_VTF16E14_Y(
 325                                                 data_bytes, exponent, val);
 326
 327                                 case 2:
 328                                         return  correction *
 329                                                 CONVERT_M_MG_VTF16E14_Z(
 330                                                 data_bytes, exponent, val);
 331                         }
 332                         break;
 333
 334                 case SENSOR_TYPE_ORIENTATION:
 335                         return  correction * convert_from_vtf_format(
 336                                                 data_bytes, exponent, val);
 337
 338                 case SENSOR_TYPE_ROTATION_VECTOR:
 339                         return  correction * convert_from_vtf_format(
 340                                                 data_bytes, exponent, val);
 341         }
 342
 343         return 0;
 344 }
 345
 346
 347 void select_transform (int s)
 348 {
 349         char prop_name[PROP_NAME_MAX];
 350         char prop_val[PROP_VALUE_MAX];
 351         int i                   = sensor_info[s].catalog_index;
 352         const char *prefix      = sensor_catalog[i].tag;
 353
 354         sprintf(prop_name, PROP_BASE, prefix, "transform");
 355
 356         if (property_get(prop_name, prop_val, "")) {
 357                 if (!strcmp(prop_val, "ISH")) {
 358                         ALOGI(  "Using Intel Sensor Hub semantics on %s\n",
 359                                 sensor_info[s].friendly_name);
 360
 361                         sensor_info[s].ops.transform = transform_sample_ISH;
 362                         sensor_info[s].ops.finalize = finalize_sample_ISH;
 363                         return;
 364                 }
 365         }
 366
 367         sensor_info[s].ops.transform = transform_sample_default;
 368         sensor_info[s].ops.finalize = finalize_sample_default;
 369 }
 370
 371
 372 float acquire_immediate_value(int s, int c)
 373 {
 374         char sysfs_path[PATH_MAX];
 375         float val;
 376         int ret;
 377         int dev_num = sensor_info[s].dev_num;
 378         int i = sensor_info[s].catalog_index;
 379         const char* raw_path = sensor_catalog[i].channel[c].raw_path;
 380         const char* input_path = sensor_catalog[i].channel[c].input_path;
 381         float scale = sensor_info[s].scale ?
 382                         sensor_info[s].scale : sensor_info[s].channel[c].scale;
 383         float offset = sensor_info[s].offset;
 384         int sensor_type = sensor_catalog[i].type;
 385         float correction;
 386
 387         /* In case correction has been requested using properties, apply it */
 388         correction = sensor_info[s].channel[c].opt_scale;
 389
 390         /* Acquire a sample value for sensor s / channel c through sysfs */
 391
 392         if (input_path[0]) {
 393                 sprintf(sysfs_path, BASE_PATH "%s", dev_num, input_path);
 394                 ret = sysfs_read_float(sysfs_path, &val);
 395
 396                 if (!ret) {
 397                         return val * correction;
 398                 }
 399         };
 400
 401         if (!raw_path[0])
 402                 return 0;
 403
 404         sprintf(sysfs_path, BASE_PATH "%s", dev_num, raw_path);
 405         ret = sysfs_read_float(sysfs_path, &val);
 406
 407         if (ret == -1)
 408                 return 0;
 409
 410         /*
 411         There is no transform ops defined yet for Raw sysfs values
 412         Use this function to perform transformation as well.
 413         */
 414         if (sensor_type == SENSOR_TYPE_MAGNETIC_FIELD)
 415                 return  CONVERT_GAUSS_TO_MICROTESLA ((val + offset) * scale) *
 416                         correction;
 417
 418         return (val + offset) * scale * correction;
 419 }