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; 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 16:
 154                         return (int64_t) (int16_t) u64;
 155
 156                 case 32:
 157                         return (int64_t) (int32_t) u64;
 158
 159                 case 64:
 160                         return (int64_t) u64;
 161         }
 162
 163         ALOGE("Unhandled sample storage size\n");
 164         return 0;
 165 }
 166
 167
 168 static void finalize_sample_default(int s, struct sensors_event_t* data)
 169 {
 170         int i           = sensor_info[s].catalog_index;
 171         int sensor_type = sensor_catalog[i].type;
 172
 173         switch (sensor_type) {
 174                 case SENSOR_TYPE_ACCELEROMETER:
 175                         /*
 176                          * Invert x and z axes orientation from SI units - see
 177                          * /hardware/libhardware/include/hardware/sensors.h
 178                          * for a discussion of what Android expects
 179                          */
 180                         data->data[0] = -data->data[0];
 181                         data->data[2] = -data->data[2];
 182                         break;
 183
 184                 case SENSOR_TYPE_GYROSCOPE:
 185                         /* Limit drift */
 186                         if (    fabs(data->data[0]) < 0.1 &&
 187                                 fabs(data->data[1]) < 0.1 &&
 188                                 fabs(data->data[2]) < 0.1) {
 189                                         data->data[0] = 0;
 190                                         data->data[1] = 0;
 191                                         data->data[2] = 0;
 192                                 }
 193                         break;
 194         }
 195 }
 196
 197
 198 static float transform_sample_default(int s, int c, unsigned char* sample_data)
 199 {
 200         struct datum_info_t* sample_type = &sensor_info[s].channel[c].type_info;
 201         int64_t              s64 = sample_as_int64(sample_data, sample_type);
 202
 203         /* Apply default scaling rules */
 204         return (sensor_info[s].offset + s64) * sensor_info[s].scale;
 205 }
 206
 207
 208 static void finalize_sample_ISH(int s, struct sensors_event_t* data)
 209 {
 210         int i           = sensor_info[s].catalog_index;
 211         int sensor_type = sensor_catalog[i].type;
 212         float pitch, roll, yaw;
 213
 214         if (sensor_type == SENSOR_TYPE_ORIENTATION) {
 215
 216                 pitch = data->data[0];
 217                 roll = data->data[1];
 218                 yaw = data->data[2];
 219
 220                 data->data[0] = 360.0 - yaw;
 221                 data->data[1] = -pitch;
 222                 data->data[2] = -roll;
 223         }
 224 }
 225
 226
 227 static float transform_sample_ISH(int s, int c, unsigned char* sample_data)
 228 {
 229         struct datum_info_t* sample_type = &sensor_info[s].channel[c].type_info;
 230         int val         = (int) sample_as_int64(sample_data, sample_type);
 231         int i           = sensor_info[s].catalog_index;
 232         int sensor_type = sensor_catalog[i].type;
 233
 234         switch (sensor_type) {
 235                 case SENSOR_TYPE_ACCELEROMETER:
 236                         switch (c) {
 237                                 case 0:
 238                                         return CONVERT_A_G_VTF16E14_X(
 239                                                 DATA_BYTES, ACC_EXPONENT, val);
 240
 241                                 case 1:
 242                                         return CONVERT_A_G_VTF16E14_Y(
 243                                                 DATA_BYTES, ACC_EXPONENT, val);
 244
 245                                 case 2:
 246                                         return CONVERT_A_G_VTF16E14_Z(
 247                                                 DATA_BYTES, ACC_EXPONENT, val);
 248                         }
 249                         break;
 250
 251
 252                 case SENSOR_TYPE_GYROSCOPE:
 253                         switch (c) {
 254                                 case 0:
 255                                         return CONVERT_G_D_VTF16E14_X(
 256                                                 DATA_BYTES, GYRO_EXPONENT, val);
 257
 258                                 case 1:
 259                                         return CONVERT_G_D_VTF16E14_Y(
 260                                                 DATA_BYTES, GYRO_EXPONENT, val);
 261
 262                                 case 2:
 263                                         return CONVERT_G_D_VTF16E14_Z(
 264                                                 DATA_BYTES, GYRO_EXPONENT, val);
 265                         }
 266                         break;
 267
 268                 case SENSOR_TYPE_MAGNETIC_FIELD:
 269                         switch (c) {
 270                                 case 0:
 271                                         return CONVERT_M_MG_VTF16E14_X(
 272                                                 DATA_BYTES, MAGN_EXPONENT, val);
 273
 274                                 case 1:
 275                                         return CONVERT_M_MG_VTF16E14_Y(
 276                                                 DATA_BYTES, MAGN_EXPONENT, val);
 277
 278                                 case 2:
 279                                         return CONVERT_M_MG_VTF16E14_Z(
 280                                                 DATA_BYTES, MAGN_EXPONENT, val);
 281                         }
 282                         break;
 283
 284                 case SENSOR_TYPE_ORIENTATION:
 285                         return convert_from_vtf_format(DATA_BYTES, INC_EXPONENT,
 286                                 val);
 287
 288                 case SENSOR_TYPE_ROTATION_VECTOR:
 289                         return convert_from_vtf_format(DATA_BYTES, ROT_EXPONENT,
 290                                 val);
 291         }
 292
 293         return 0;
 294 }
 295
 296
 297 void select_transform (int s)
 298 {
 299         char prop_name[PROP_NAME_MAX];
 300         char prop_val[PROP_VALUE_MAX];
 301         int i                   = sensor_info[s].catalog_index;
 302         const char *prefix      = sensor_catalog[i].tag;
 303
 304         sprintf(prop_name, PROP_BASE, prefix, "transform");
 305
 306         if (property_get(prop_name, prop_val, "")) {
 307                 if (!strcmp(prop_val, "ISH")) {
 308                         ALOGI(  "Using Intel Sensor Hub semantics on %s\n",
 309                                 sensor_info[s].friendly_name);
 310
 311                         sensor_info[s].ops.transform = transform_sample_ISH;
 312                         sensor_info[s].ops.finalize = finalize_sample_ISH;
 313                         return;
 314                 }
 315         }
 316
 317         sensor_info[s].ops.transform = transform_sample_default;
 318         sensor_info[s].ops.finalize = finalize_sample_default;
 319 }
 320
 321
 322 float acquire_immediate_value(int s, int c)
 323 {
 324         char sysfs_path[PATH_MAX];
 325         float val;
 326         int ret;
 327         int dev_num = sensor_info[s].dev_num;
 328         int i = sensor_info[s].catalog_index;
 329         const char* raw_path = sensor_catalog[i].channel[c].raw_path;
 330         const char* input_path = sensor_catalog[i].channel[c].input_path;
 331         float scale = sensor_info[s].scale;
 332         float offset = sensor_info[s].offset;
 333
 334         /* Acquire a sample value for sensor s / channel c through sysfs */
 335
 336         if (input_path[0]) {
 337                 sprintf(sysfs_path, BASE_PATH "%s", dev_num, input_path);
 338                 ret = sysfs_read_float(sysfs_path, &val);
 339
 340                 if (!ret) {
 341                         return val;
 342                 }
 343         };
 344
 345         if (!raw_path[0])
 346                 return 0;
 347
 348         sprintf(sysfs_path, BASE_PATH "%s", dev_num, raw_path);
 349         ret = sysfs_read_float(sysfs_path, &val);
 350
 351         if (ret == -1)
 352                 return 0;
 353
 354         return (val + offset) * scale;
 355 }