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
  14 /*----------------------------------------------------------------------------*/
  15
  16 /* Macros related to Intel Sensor Hub */
  17
  18 #define GRAVITY 9.80665f
  19
  20 /* 720 LSG = 1G */
  21 #define LSG                         (1024.0f)
  22 #define NUMOFACCDATA                (8.0f)
  23
  24 /* conversion of acceleration data to SI units (m/s^2) */
  25 #define CONVERT_A                   (GRAVITY_EARTH / LSG / NUMOFACCDATA)
  26 #define CONVERT_A_X(x)              ((float(x)/1000) * (GRAVITY * -1.0))
  27 #define CONVERT_A_Y(x)              ((float(x)/1000) * (GRAVITY * 1.0))
  28 #define CONVERT_A_Z(x)              ((float(x)/1000) * (GRAVITY * 1.0))
  29
  30 /* conversion of magnetic data to uT units */
  31 #define CONVERT_M                   (1.0f/6.6f)
  32 #define CONVERT_M_X                 (-CONVERT_M)
  33 #define CONVERT_M_Y                 (-CONVERT_M)
  34 #define CONVERT_M_Z                 (CONVERT_M)
  35
  36 #define CONVERT_GAUSS_TO_MICROTESLA(x)        ( (x) * 100 )
  37
  38 /* conversion of orientation data to degree units */
  39 #define CONVERT_O                   (1.0f/64.0f)
  40 #define CONVERT_O_A                 (CONVERT_O)
  41 #define CONVERT_O_P                 (CONVERT_O)
  42 #define CONVERT_O_R                 (-CONVERT_O)
  43
  44 /*conversion of gyro data to SI units (radian/sec) */
  45 #define CONVERT_GYRO                ((2000.0f/32767.0f)*((float)M_PI / 180.0f))
  46 #define CONVERT_GYRO_X              (-CONVERT_GYRO)
  47 #define CONVERT_GYRO_Y              (-CONVERT_GYRO)
  48 #define CONVERT_GYRO_Z              (CONVERT_GYRO)
  49
  50 #define BIT(x) (1 << (x))
  51
  52 inline unsigned int set_bit_range(int start, int end)
  53 {
  54     int i;
  55     unsigned int value = 0;
  56
  57     for (i = start; i < end; ++i)
  58         value |= BIT(i);
  59     return value;
  60 }
  61
  62 inline float convert_from_vtf_format(int size, int exponent, unsigned int value)
  63 {
  64     int divider=1;
  65     int i;
  66     float sample;
  67     int mul = 1.0;
  68
  69     value = value & set_bit_range(0, size*8);
  70     if (value & BIT(size*8-1)) {
  71         value =  ((1LL << (size*8)) - value);
  72         mul = -1.0;
  73     }
  74     sample = value * 1.0;
  75     if (exponent < 0) {
  76         exponent = abs(exponent);
  77         for (i = 0; i < exponent; ++i) {
  78             divider = divider*10;
  79         }
  80         return mul * sample/divider;
  81     } else {
  82         return mul * sample * pow(10.0, exponent);
  83     }
  84 }
  85
  86 // Platform sensor orientation
  87 #define DEF_ORIENT_ACCEL_X                   -1
  88 #define DEF_ORIENT_ACCEL_Y                   -1
  89 #define DEF_ORIENT_ACCEL_Z                   -1
  90
  91 #define DEF_ORIENT_GYRO_X                   1
  92 #define DEF_ORIENT_GYRO_Y                   1
  93 #define DEF_ORIENT_GYRO_Z                   1
  94
  95 // G to m/s2
  96 #define CONVERT_FROM_VTF16(s,d,x)      (convert_from_vtf_format(s,d,x))
  97 #define CONVERT_A_G_VTF16E14_X(s,d,x)  (DEF_ORIENT_ACCEL_X *\
  98                                         convert_from_vtf_format(s,d,x)*GRAVITY)
  99 #define CONVERT_A_G_VTF16E14_Y(s,d,x)  (DEF_ORIENT_ACCEL_Y *\
 100                                         convert_from_vtf_format(s,d,x)*GRAVITY)
 101 #define CONVERT_A_G_VTF16E14_Z(s,d,x)  (DEF_ORIENT_ACCEL_Z *\
 102                                         convert_from_vtf_format(s,d,x)*GRAVITY)
 103
 104 // Degree/sec to radian/sec
 105 #define CONVERT_G_D_VTF16E14_X(s,d,x)  (DEF_ORIENT_GYRO_X *\
 106                                         convert_from_vtf_format(s,d,x) * \
 107                                         ((float)M_PI/180.0f))
 108 #define CONVERT_G_D_VTF16E14_Y(s,d,x)  (DEF_ORIENT_GYRO_Y *\
 109                                         convert_from_vtf_format(s,d,x) * \
 110                                         ((float)M_PI/180.0f))
 111 #define CONVERT_G_D_VTF16E14_Z(s,d,x)  (DEF_ORIENT_GYRO_Z *\
 112                                         convert_from_vtf_format(s,d,x) * \
 113                                         ((float)M_PI/180.0f))
 114
 115 // Milli gauss to micro tesla
 116 #define CONVERT_M_MG_VTF16E14_X(s,d,x) (convert_from_vtf_format(s,d,x)/10)
 117 #define CONVERT_M_MG_VTF16E14_Y(s,d,x) (convert_from_vtf_format(s,d,x)/10)
 118 #define CONVERT_M_MG_VTF16E14_Z(s,d,x) (convert_from_vtf_format(s,d,x)/10)
 119
 120 #define DATA_BYTES      2
 121 #define ACC_EXPONENT    -2
 122 #define GYRO_EXPONENT   -1
 123 #define MAGN_EXPONENT   0
 124 #define INC_EXPONENT    -1
 125 #define ROT_EXPONENT    -8
 126
 127 /*----------------------------------------------------------------------------*/
 128
 129 static int64_t sample_as_int64(unsigned char* sample, struct datum_info_t* type)
 130 {
 131         uint16_t u16;
 132         uint32_t u32;
 133         uint64_t u64;
 134         int i;
 135         int zeroed_bits = type->storagebits - type->realbits;
 136
 137         u64 = 0;
 138
 139         if (type->endianness == 'b')
 140                 for (i=0; i<type->storagebits/8; i++)
 141                         u64 = (u64 << 8) | sample[i];
 142         else
 143                 for (i=type->storagebits/8 - 1; i>=0; i--)
 144                         u64 = (u64 << 8) | sample[i];
 145
 146         u64 = (u64 >> type->shift) & (~0ULL >> zeroed_bits);
 147
 148         if (type->sign == 'u')
 149                 return (int64_t) u64; /* We don't handle unsigned 64 bits int */
 150
 151         switch (type->realbits) {
 152                 case 8:
 153                         return (int64_t) (int8_t) u64;
 154
 155                 case 12:
 156                         return (int64_t)  (u64 >>  11) ?
 157                                         (((int64_t)-1) ^ 0xfff) | u64 : u64;
 158
 159                 case 16:
 160                         return (int64_t) (int16_t) u64;
 161
 162                 case 32:
 163                         return (int64_t) (int32_t) u64;
 164
 165                 case 64:
 166                         return (int64_t) u64;
 167         }
 168
 169         ALOGE("Unhandled sample storage size\n");
 170         return 0;
 171 }
 172
 173
 174 static void finalize_sample_default(int s, struct sensors_event_t* data)
 175 {
 176         int i           = sensor_info[s].catalog_index;
 177         int sensor_type = sensor_catalog[i].type;
 178         float x, y, z;
 179
 180         switch (sensor_type) {
 181                 case SENSOR_TYPE_ACCELEROMETER:
 182                         /*
 183                          * Invert x and z axes orientation from SI units - see
 184                          * /hardware/libhardware/include/hardware/sensors.h
 185                          * for a discussion of what Android expects
 186                          */
 187                         x = -data->data[0];
 188                         y = data->data[1];
 189                         z = -data->data[2];
 190
 191                         data->data[0] = x;
 192                         data->data[1] = y;
 193                         data->data[2] = z;
 194                         break;
 195
 196                 case SENSOR_TYPE_MAGNETIC_FIELD:
 197                         x = -data->data[0];
 198                         y = data->data[1];
 199                         z = -data->data[2];
 200
 201                         data->data[0] = x;
 202                         data->data[1] = y;
 203                         data->data[2] = z;
 204                         break;
 205
 206                 case SENSOR_TYPE_GYROSCOPE:
 207                         x = -data->data[0];
 208                         y = data->data[1];
 209                         z = -data->data[2];
 210
 211                         /* Limit drift */
 212                         if (fabs(x) < 0.1 && fabs(y) < 0.1 && fabs(z) < 0.1)
 213                                 x = y = z = 0;
 214
 215                         data->data[0] = x;
 216                         data->data[1] = y;
 217                         data->data[2] = z;
 218                         break;
 219
 220                 case SENSOR_TYPE_AMBIENT_TEMPERATURE:
 221                 case SENSOR_TYPE_TEMPERATURE:
 222                         /* Only keep two decimals for temperature readings */
 223                         data->data[0] = 0.01 * ((int) (data->data[0] * 100));
 224                         break;
 225         }
 226 }
 227
 228
 229 static float transform_sample_default(int s, int c, unsigned char* sample_data)
 230 {
 231         struct datum_info_t* sample_type = &sensor_info[s].channel[c].type_info;
 232         int64_t              s64 = sample_as_int64(sample_data, sample_type);
 233
 234         /* Apply default scaling rules */
 235         return (sensor_info[s].offset + s64) * sensor_info[s].scale;
 236 }
 237
 238
 239 static void finalize_sample_ISH(int s, struct sensors_event_t* data)
 240 {
 241         int i           = sensor_info[s].catalog_index;
 242         int sensor_type = sensor_catalog[i].type;
 243         float pitch, roll, yaw;
 244
 245         if (sensor_type == SENSOR_TYPE_ORIENTATION) {
 246
 247                 pitch = data->data[0];
 248                 roll = data->data[1];
 249                 yaw = data->data[2];
 250
 251                 data->data[0] = 360.0 - yaw;
 252                 data->data[1] = -pitch;
 253                 data->data[2] = -roll;
 254         }
 255 }
 256
 257
 258 static float transform_sample_ISH(int s, int c, unsigned char* sample_data)
 259 {
 260         struct datum_info_t* sample_type = &sensor_info[s].channel[c].type_info;
 261         int val         = (int) sample_as_int64(sample_data, sample_type);
 262         int i           = sensor_info[s].catalog_index;
 263         int sensor_type = sensor_catalog[i].type;
 264
 265         switch (sensor_type) {
 266                 case SENSOR_TYPE_ACCELEROMETER:
 267                         switch (c) {
 268                                 case 0:
 269                                         return CONVERT_A_G_VTF16E14_X(
 270                                                 DATA_BYTES, ACC_EXPONENT, val);
 271
 272                                 case 1:
 273                                         return CONVERT_A_G_VTF16E14_Y(
 274                                                 DATA_BYTES, ACC_EXPONENT, val);
 275
 276                                 case 2:
 277                                         return CONVERT_A_G_VTF16E14_Z(
 278                                                 DATA_BYTES, ACC_EXPONENT, val);
 279                         }
 280                         break;
 281
 282
 283                 case SENSOR_TYPE_GYROSCOPE:
 284                         switch (c) {
 285                                 case 0:
 286                                         return CONVERT_G_D_VTF16E14_X(
 287                                                 DATA_BYTES, GYRO_EXPONENT, val);
 288
 289                                 case 1:
 290                                         return CONVERT_G_D_VTF16E14_Y(
 291                                                 DATA_BYTES, GYRO_EXPONENT, val);
 292
 293                                 case 2:
 294                                         return CONVERT_G_D_VTF16E14_Z(
 295                                                 DATA_BYTES, GYRO_EXPONENT, val);
 296                         }
 297                         break;
 298
 299                 case SENSOR_TYPE_MAGNETIC_FIELD:
 300                         switch (c) {
 301                                 case 0:
 302                                         return CONVERT_M_MG_VTF16E14_X(
 303                                                 DATA_BYTES, MAGN_EXPONENT, val);
 304
 305                                 case 1:
 306                                         return CONVERT_M_MG_VTF16E14_Y(
 307                                                 DATA_BYTES, MAGN_EXPONENT, val);
 308
 309                                 case 2:
 310                                         return CONVERT_M_MG_VTF16E14_Z(
 311                                                 DATA_BYTES, MAGN_EXPONENT, val);
 312                         }
 313                         break;
 314
 315                 case SENSOR_TYPE_ORIENTATION:
 316                         return convert_from_vtf_format(DATA_BYTES, INC_EXPONENT,
 317                                 val);
 318
 319                 case SENSOR_TYPE_ROTATION_VECTOR:
 320                         return convert_from_vtf_format(DATA_BYTES, ROT_EXPONENT,
 321                                 val);
 322         }
 323
 324         return 0;
 325 }
 326
 327
 328 void select_transform (int s)
 329 {
 330         char prop_name[PROP_NAME_MAX];
 331         char prop_val[PROP_VALUE_MAX];
 332         int i                   = sensor_info[s].catalog_index;
 333         const char *prefix      = sensor_catalog[i].tag;
 334
 335         sprintf(prop_name, PROP_BASE, prefix, "transform");
 336
 337         if (property_get(prop_name, prop_val, "")) {
 338                 if (!strcmp(prop_val, "ISH")) {
 339                         ALOGI(  "Using Intel Sensor Hub semantics on %s\n",
 340                                 sensor_info[s].friendly_name);
 341
 342                         sensor_info[s].ops.transform = transform_sample_ISH;
 343                         sensor_info[s].ops.finalize = finalize_sample_ISH;
 344                         return;
 345                 }
 346         }
 347
 348         sensor_info[s].ops.transform = transform_sample_default;
 349         sensor_info[s].ops.finalize = finalize_sample_default;
 350 }
 351
 352
 353 float acquire_immediate_value(int s, int c)
 354 {
 355         char sysfs_path[PATH_MAX];
 356         float val;
 357         int ret;
 358         int dev_num = sensor_info[s].dev_num;
 359         int i = sensor_info[s].catalog_index;
 360         const char* raw_path = sensor_catalog[i].channel[c].raw_path;
 361         const char* input_path = sensor_catalog[i].channel[c].input_path;
 362         float scale = sensor_info[s].scale;
 363         float offset = sensor_info[s].offset;
 364         int sensor_type = sensor_catalog[i].type;
 365
 366         /* Acquire a sample value for sensor s / channel c through sysfs */
 367
 368         if (input_path[0]) {
 369                 sprintf(sysfs_path, BASE_PATH "%s", dev_num, input_path);
 370                 ret = sysfs_read_float(sysfs_path, &val);
 371
 372                 if (!ret) {
 373                         return val;
 374                 }
 375         };
 376
 377         if (!raw_path[0])
 378                 return 0;
 379
 380         sprintf(sysfs_path, BASE_PATH "%s", dev_num, raw_path);
 381         ret = sysfs_read_float(sysfs_path, &val);
 382
 383         if (ret == -1)
 384                 return 0;
 385
 386         /*
 387         There is no transform ops defined yet for Raw sysfs values
 388         Use this function to perform transformation as well.
 389         */
 390         if (sensor_type == SENSOR_TYPE_MAGNETIC_FIELD)
 391                 return CONVERT_GAUSS_TO_MICROTESLA ((val + offset) * scale); //Gauss to MicroTesla
 392
 393         return (val + offset) * scale;
 394 }