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