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
  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
 134         switch (type->storagebits) {
 135                 case 64:
 136                         u64 = 0;
 137
 138                         if (type->endianness == 'b')
 139                                 for (i=0; i<8; i++)
 140                                         u64 = (u64 << 8) | sample[i];
 141                         else
 142                                 for (i=7; i>=0; i--)
 143                                         u64 = (u64 << 8) | sample[i];
 144
 145                         if (type->sign == 'u')
 146                                 return (int64_t) (u64 >> type->shift);
 147
 148                         return ((int64_t) u64) >> type->shift;
 149
 150                 case 32:
 151                         if (type->endianness == 'b')
 152                                 u32 = (sample[0] << 24) | (sample[1] << 16) |
 153                                         (sample[2] << 8) | sample[3];
 154                         else
 155                                 u32 = (sample[3] << 24) | (sample[2] << 16) |
 156                                         (sample[1] << 8) | sample[0];
 157
 158                         if (type->sign == 'u')
 159                                 return u32 >> type->shift;
 160
 161                         return ((int32_t) u32) >> type->shift;
 162
 163                 case 16:
 164                         if (type->endianness == 'b')
 165                                 u16 = (sample[0] << 8) | sample[1];
 166                         else
 167                                 u16 = (sample[1] << 8) | sample[0];
 168
 169                         if (type->sign == 'u')
 170                                 return u16 >> type->shift;
 171
 172                         return  ((int16_t) u16) >> type->shift;
 173         }
 174
 175         ALOGE("Unhandled sample storage size\n");
 176         return 0;
 177 }
 178
 179
 180 static void finalize_sample_default(int s, struct sensors_event_t* data)
 181 {
 182         int i           = sensor_info[s].catalog_index;
 183         int sensor_type = sensor_catalog[i].type;
 184
 185         switch (sensor_type) {
 186                 case SENSOR_TYPE_ACCELEROMETER:
 187                         /*
 188                          * Invert x axis orientation from SI units - see
 189                          * /hardware/libhardware/include/hardware/sensors.h
 190                          * for a discussion of what Android expects
 191                          */
 192                         data->data[0] = -data->data[0];
 193                         break;
 194
 195                 case SENSOR_TYPE_GYROSCOPE:
 196                         /* Limit drift */
 197                         if (abs(data->data[0]) < .05 && abs(data->data[1]) < .05
 198                                 && abs(data->data[2]) < .05) {
 199                                         data->data[0] = 0;
 200                                         data->data[1] = 0;
 201                                         data->data[2] = 0;
 202                                 }
 203                         break;
 204         }
 205 }
 206
 207
 208 static float transform_sample_default(int s, int c, unsigned char* sample_data)
 209 {
 210         struct datum_info_t* sample_type = &sensor_info[s].channel[c].type_info;
 211         int64_t              s64 = sample_as_int64(sample_data, sample_type);
 212
 213         /* Apply default scaling rules */
 214         return (sensor_info[s].offset + s64) * sensor_info[s].scale;
 215 }
 216
 217
 218 static void finalize_sample_ISH(int s, struct sensors_event_t* data)
 219 {
 220         int i           = sensor_info[s].catalog_index;
 221         int sensor_type = sensor_catalog[i].type;
 222         float pitch, roll, yaw;
 223
 224         if (sensor_type == SENSOR_TYPE_ORIENTATION) {
 225
 226                 pitch = data->data[0];
 227                 roll = data->data[1];
 228                 yaw = data->data[2];
 229
 230                 data->data[0] = 360.0 - yaw;
 231                 data->data[1] = -pitch;
 232                 data->data[2] = -roll;
 233         }
 234 }
 235
 236
 237 static float transform_sample_ISH(int s, int c, unsigned char* sample_data)
 238 {
 239         struct datum_info_t* sample_type = &sensor_info[s].channel[c].type_info;
 240         int val         = (int) sample_as_int64(sample_data, sample_type);
 241         int i           = sensor_info[s].catalog_index;
 242         int sensor_type = sensor_catalog[i].type;
 243
 244         switch (sensor_type) {
 245                 case SENSOR_TYPE_ACCELEROMETER:
 246                         switch (c) {
 247                                 case 0:
 248                                         return CONVERT_A_G_VTF16E14_X(
 249                                                 DATA_BYTES, ACC_EXPONENT, val);
 250
 251                                 case 1:
 252                                         return CONVERT_A_G_VTF16E14_Y(
 253                                                 DATA_BYTES, ACC_EXPONENT, val);
 254
 255                                 case 2:
 256                                         return CONVERT_A_G_VTF16E14_Z(
 257                                                 DATA_BYTES, ACC_EXPONENT, val);
 258                         }
 259                         break;
 260
 261
 262                 case SENSOR_TYPE_GYROSCOPE:
 263                         switch (c) {
 264                                 case 0:
 265                                         return CONVERT_G_D_VTF16E14_X(
 266                                                 DATA_BYTES, GYRO_EXPONENT, val);
 267
 268                                 case 1:
 269                                         return CONVERT_G_D_VTF16E14_Y(
 270                                                 DATA_BYTES, GYRO_EXPONENT, val);
 271
 272                                 case 2:
 273                                         return CONVERT_G_D_VTF16E14_Z(
 274                                                 DATA_BYTES, GYRO_EXPONENT, val);
 275                         }
 276                         break;
 277
 278                 case SENSOR_TYPE_MAGNETIC_FIELD:
 279                         switch (c) {
 280                                 case 0:
 281                                         return CONVERT_M_MG_VTF16E14_X(
 282                                                 DATA_BYTES, MAGN_EXPONENT, val);
 283
 284                                 case 1:
 285                                         return CONVERT_M_MG_VTF16E14_Y(
 286                                                 DATA_BYTES, MAGN_EXPONENT, val);
 287
 288                                 case 2:
 289                                         return CONVERT_M_MG_VTF16E14_Z(
 290                                                 DATA_BYTES, MAGN_EXPONENT, val);
 291                         }
 292                         break;
 293
 294                 case SENSOR_TYPE_ORIENTATION:
 295                         return convert_from_vtf_format(DATA_BYTES, INC_EXPONENT,
 296                                 val);
 297
 298                 case SENSOR_TYPE_ROTATION_VECTOR:
 299                         return convert_from_vtf_format(DATA_BYTES, ROT_EXPONENT,
 300                                 val);
 301         }
 302
 303         return 0;
 304 }
 305
 306
 307 void select_transform (int s)
 308 {
 309         char prop_name[PROP_NAME_MAX];
 310         char prop_val[PROP_VALUE_MAX];
 311         int i                   = sensor_info[s].catalog_index;
 312         const char *prefix      = sensor_catalog[i].tag;
 313
 314         sprintf(prop_name, PROP_BASE, prefix, "transform");
 315
 316         if (property_get(prop_name, prop_val, "")) {
 317                 if (!strcmp(prop_val, "ISH")) {
 318                         ALOGI(  "Using Intel Sensor Hub semantics on %s\n",
 319                                 sensor_info[s].friendly_name);
 320
 321                         sensor_info[s].ops.transform = transform_sample_ISH;
 322                         sensor_info[s].ops.finalize = finalize_sample_ISH;
 323                         return;
 324                 }
 325         }
 326
 327         sensor_info[s].ops.transform = transform_sample_default;
 328         sensor_info[s].ops.finalize = finalize_sample_default;
 329 }