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 #define DATA_BYTES      2
 122 #define ACC_EXPONENT    -2
 123 #define GYRO_EXPONENT   -1
 124 #define MAGN_EXPONENT   0
 125 #define INC_EXPONENT    -1
 126 #define ROT_EXPONENT    -8
 127
 128 /*----------------------------------------------------------------------------*/
 129
 130 static int64_t sample_as_int64(unsigned char* sample, struct datum_info_t* type)
 131 {
 132         uint16_t u16;
 133         uint32_t u32;
 134         uint64_t u64;
 135         int i;
 136         int zeroed_bits = type->storagebits - type->realbits;
 137
 138         u64 = 0;
 139
 140         if (type->endianness == 'b')
 141                 for (i=0; i<type->storagebits/8; i++)
 142                         u64 = (u64 << 8) | sample[i];
 143         else
 144                 for (i=type->storagebits/8 - 1; i>=0; i--)
 145                         u64 = (u64 << 8) | sample[i];
 146
 147         u64 = (u64 >> type->shift) & (~0ULL >> zeroed_bits);
 148
 149         if (type->sign == 'u')
 150                 return (int64_t) u64; /* We don't handle unsigned 64 bits int */
 151
 152         switch (type->realbits) {
 153                 case 8:
 154                         return (int64_t) (int8_t) u64;
 155
 156                 case 12:
 157                         return (int64_t)  (u64 >>  11) ?
 158                                         (((int64_t)-1) ^ 0xfff) | u64 : u64;
 159
 160                 case 16:
 161                         return (int64_t) (int16_t) u64;
 162
 163                 case 32:
 164                         return (int64_t) (int32_t) u64;
 165
 166                 case 64:
 167                         return (int64_t) u64;
 168         }
 169
 170         ALOGE("Unhandled sample storage size\n");
 171         return 0;
 172 }
 173
 174
 175 static void finalize_sample_default(int s, struct sensors_event_t* data)
 176 {
 177         int i           = sensor_info[s].catalog_index;
 178         int sensor_type = sensor_catalog[i].type;
 179         float x, y, z;
 180
 181         switch (sensor_type) {
 182                 case SENSOR_TYPE_ACCELEROMETER:
 183                         /*
 184                          * Invert x and z axes orientation from SI units - see
 185                          * /hardware/libhardware/include/hardware/sensors.h
 186                          * for a discussion of what Android expects
 187                          */
 188                         x = -data->data[0];
 189                         y = data->data[1];
 190                         z = -data->data[2];
 191
 192                         data->data[0] = x;
 193                         data->data[1] = y;
 194                         data->data[2] = z;
 195                         break;
 196
 197                 case SENSOR_TYPE_MAGNETIC_FIELD:
 198                         x = -data->data[0];
 199                         y = data->data[1];
 200                         z = -data->data[2];
 201
 202                         data->data[0] = x;
 203                         data->data[1] = y;
 204                         data->data[2] = z;
 205
 206                         /* Calibrate compass */
 207                         calibrate_compass (data, get_timestamp());
 208                         break;
 209
 210                 case SENSOR_TYPE_GYROSCOPE:
 211                         x = -data->data[0];
 212                         y = data->data[1];
 213                         z = -data->data[2];
 214
 215                         /* Limit drift */
 216                         if (fabs(x) < 0.1 && fabs(y) < 0.1 && fabs(z) < 0.1)
 217                                 x = y = z = 0;
 218
 219                         data->data[0] = x;
 220                         data->data[1] = y;
 221                         data->data[2] = z;
 222                         break;
 223
 224                 case SENSOR_TYPE_AMBIENT_TEMPERATURE:
 225                 case SENSOR_TYPE_TEMPERATURE:
 226                         /* Only keep two decimals for temperature readings */
 227                         data->data[0] = 0.01 * ((int) (data->data[0] * 100));
 228                         break;
 229
 230         }
 231 }
 232
 233
 234 static float transform_sample_default(int s, int c, unsigned char* sample_data)
 235 {
 236         struct datum_info_t* sample_type = &sensor_info[s].channel[c].type_info;
 237         int64_t              s64 = sample_as_int64(sample_data, sample_type);
 238         float scale = sensor_info[s].scale ?
 239                         sensor_info[s].scale : sensor_info[s].channel[c].scale;
 240         /* Apply default scaling rules */
 241         return (sensor_info[s].offset + s64) * scale;
 242 }
 243
 244
 245 static void finalize_sample_ISH(int s, struct sensors_event_t* data)
 246 {
 247         int i           = sensor_info[s].catalog_index;
 248         int sensor_type = sensor_catalog[i].type;
 249         float pitch, roll, yaw;
 250
 251         if (sensor_type == SENSOR_TYPE_ORIENTATION) {
 252
 253                 pitch = data->data[0];
 254                 roll = data->data[1];
 255                 yaw = data->data[2];
 256
 257                 data->data[0] = 360.0 - yaw;
 258                 data->data[1] = -pitch;
 259                 data->data[2] = -roll;
 260         }
 261 }
 262
 263
 264 static float transform_sample_ISH(int s, int c, unsigned char* sample_data)
 265 {
 266         struct datum_info_t* sample_type = &sensor_info[s].channel[c].type_info;
 267         int val         = (int) sample_as_int64(sample_data, sample_type);
 268         int i           = sensor_info[s].catalog_index;
 269         int sensor_type = sensor_catalog[i].type;
 270
 271         switch (sensor_type) {
 272                 case SENSOR_TYPE_ACCELEROMETER:
 273                         switch (c) {
 274                                 case 0:
 275                                         return CONVERT_A_G_VTF16E14_X(
 276                                                 DATA_BYTES, ACC_EXPONENT, val);
 277
 278                                 case 1:
 279                                         return CONVERT_A_G_VTF16E14_Y(
 280                                                 DATA_BYTES, ACC_EXPONENT, val);
 281
 282                                 case 2:
 283                                         return CONVERT_A_G_VTF16E14_Z(
 284                                                 DATA_BYTES, ACC_EXPONENT, val);
 285                         }
 286                         break;
 287
 288
 289                 case SENSOR_TYPE_GYROSCOPE:
 290                         switch (c) {
 291                                 case 0:
 292                                         return CONVERT_G_D_VTF16E14_X(
 293                                                 DATA_BYTES, GYRO_EXPONENT, val);
 294
 295                                 case 1:
 296                                         return CONVERT_G_D_VTF16E14_Y(
 297                                                 DATA_BYTES, GYRO_EXPONENT, val);
 298
 299                                 case 2:
 300                                         return CONVERT_G_D_VTF16E14_Z(
 301                                                 DATA_BYTES, GYRO_EXPONENT, val);
 302                         }
 303                         break;
 304
 305                 case SENSOR_TYPE_MAGNETIC_FIELD:
 306                         switch (c) {
 307                                 case 0:
 308                                         return CONVERT_M_MG_VTF16E14_X(
 309                                                 DATA_BYTES, MAGN_EXPONENT, val);
 310
 311                                 case 1:
 312                                         return CONVERT_M_MG_VTF16E14_Y(
 313                                                 DATA_BYTES, MAGN_EXPONENT, val);
 314
 315                                 case 2:
 316                                         return CONVERT_M_MG_VTF16E14_Z(
 317                                                 DATA_BYTES, MAGN_EXPONENT, val);
 318                         }
 319                         break;
 320
 321                 case SENSOR_TYPE_ORIENTATION:
 322                         return convert_from_vtf_format(DATA_BYTES, INC_EXPONENT,
 323                                 val);
 324
 325                 case SENSOR_TYPE_ROTATION_VECTOR:
 326                         return convert_from_vtf_format(DATA_BYTES, ROT_EXPONENT,
 327                                 val);
 328         }
 329
 330         return 0;
 331 }
 332
 333
 334 void select_transform (int s)
 335 {
 336         char prop_name[PROP_NAME_MAX];
 337         char prop_val[PROP_VALUE_MAX];
 338         int i                   = sensor_info[s].catalog_index;
 339         const char *prefix      = sensor_catalog[i].tag;
 340
 341         sprintf(prop_name, PROP_BASE, prefix, "transform");
 342
 343         if (property_get(prop_name, prop_val, "")) {
 344                 if (!strcmp(prop_val, "ISH")) {
 345                         ALOGI(  "Using Intel Sensor Hub semantics on %s\n",
 346                                 sensor_info[s].friendly_name);
 347
 348                         sensor_info[s].ops.transform = transform_sample_ISH;
 349                         sensor_info[s].ops.finalize = finalize_sample_ISH;
 350                         return;
 351                 }
 352         }
 353
 354         sensor_info[s].ops.transform = transform_sample_default;
 355         sensor_info[s].ops.finalize = finalize_sample_default;
 356 }
 357
 358
 359 float acquire_immediate_value(int s, int c)
 360 {
 361         char sysfs_path[PATH_MAX];
 362         float val;
 363         int ret;
 364         int dev_num = sensor_info[s].dev_num;
 365         int i = sensor_info[s].catalog_index;
 366         const char* raw_path = sensor_catalog[i].channel[c].raw_path;
 367         const char* input_path = sensor_catalog[i].channel[c].input_path;
 368         float scale = sensor_info[s].scale ?
 369                         sensor_info[s].scale : sensor_info[s].channel[c].scale;
 370         float offset = sensor_info[s].offset;
 371         int sensor_type = sensor_catalog[i].type;
 372
 373         /* Acquire a sample value for sensor s / channel c through sysfs */
 374
 375         if (input_path[0]) {
 376                 sprintf(sysfs_path, BASE_PATH "%s", dev_num, input_path);
 377                 ret = sysfs_read_float(sysfs_path, &val);
 378
 379                 if (!ret) {
 380                         return val;
 381                 }
 382         };
 383
 384         if (!raw_path[0])
 385                 return 0;
 386
 387         sprintf(sysfs_path, BASE_PATH "%s", dev_num, raw_path);
 388         ret = sysfs_read_float(sysfs_path, &val);
 389
 390         if (ret == -1)
 391                 return 0;
 392
 393         /*
 394         There is no transform ops defined yet for Raw sysfs values
 395         Use this function to perform transformation as well.
 396         */
 397         if (sensor_type == SENSOR_TYPE_MAGNETIC_FIELD)
 398                 return CONVERT_GAUSS_TO_MICROTESLA ((val + offset) * scale); //Gauss to MicroTesla
 399
 400         return (val + offset) * scale;
 401 }