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 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
 177         switch (sensor_type) {
 178                 case SENSOR_TYPE_ACCELEROMETER:
 179                         /*
 180                          * Invert x and z axes orientation from SI units - see
 181                          * /hardware/libhardware/include/hardware/sensors.h
 182                          * for a discussion of what Android expects
 183                          */
 184                         data->data[0] = -data->data[0];
 185                         data->data[2] = -data->data[2];
 186                         break;
 187
 188                 case SENSOR_TYPE_GYROSCOPE:
 189                         /* Limit drift */
 190                         if (    fabs(data->data[0]) < 0.1 &&
 191                                 fabs(data->data[1]) < 0.1 &&
 192                                 fabs(data->data[2]) < 0.1) {
 193                                         data->data[0] = 0;
 194                                         data->data[1] = 0;
 195                                         data->data[2] = 0;
 196                                 }
 197                         break;
 198         }
 199 }
 200
 201
 202 static float transform_sample_default(int s, int c, unsigned char* sample_data)
 203 {
 204         struct datum_info_t* sample_type = &sensor_info[s].channel[c].type_info;
 205         int64_t              s64 = sample_as_int64(sample_data, sample_type);
 206
 207         /* Apply default scaling rules */
 208         return (sensor_info[s].offset + s64) * sensor_info[s].scale;
 209 }
 210
 211
 212 static void finalize_sample_ISH(int s, struct sensors_event_t* data)
 213 {
 214         int i           = sensor_info[s].catalog_index;
 215         int sensor_type = sensor_catalog[i].type;
 216         float pitch, roll, yaw;
 217
 218         if (sensor_type == SENSOR_TYPE_ORIENTATION) {
 219
 220                 pitch = data->data[0];
 221                 roll = data->data[1];
 222                 yaw = data->data[2];
 223
 224                 data->data[0] = 360.0 - yaw;
 225                 data->data[1] = -pitch;
 226                 data->data[2] = -roll;
 227         }
 228 }
 229
 230
 231 static float transform_sample_ISH(int s, int c, unsigned char* sample_data)
 232 {
 233         struct datum_info_t* sample_type = &sensor_info[s].channel[c].type_info;
 234         int val         = (int) sample_as_int64(sample_data, sample_type);
 235         int i           = sensor_info[s].catalog_index;
 236         int sensor_type = sensor_catalog[i].type;
 237
 238         switch (sensor_type) {
 239                 case SENSOR_TYPE_ACCELEROMETER:
 240                         switch (c) {
 241                                 case 0:
 242                                         return CONVERT_A_G_VTF16E14_X(
 243                                                 DATA_BYTES, ACC_EXPONENT, val);
 244
 245                                 case 1:
 246                                         return CONVERT_A_G_VTF16E14_Y(
 247                                                 DATA_BYTES, ACC_EXPONENT, val);
 248
 249                                 case 2:
 250                                         return CONVERT_A_G_VTF16E14_Z(
 251                                                 DATA_BYTES, ACC_EXPONENT, val);
 252                         }
 253                         break;
 254
 255
 256                 case SENSOR_TYPE_GYROSCOPE:
 257                         switch (c) {
 258                                 case 0:
 259                                         return CONVERT_G_D_VTF16E14_X(
 260                                                 DATA_BYTES, GYRO_EXPONENT, val);
 261
 262                                 case 1:
 263                                         return CONVERT_G_D_VTF16E14_Y(
 264                                                 DATA_BYTES, GYRO_EXPONENT, val);
 265
 266                                 case 2:
 267                                         return CONVERT_G_D_VTF16E14_Z(
 268                                                 DATA_BYTES, GYRO_EXPONENT, val);
 269                         }
 270                         break;
 271
 272                 case SENSOR_TYPE_MAGNETIC_FIELD:
 273                         switch (c) {
 274                                 case 0:
 275                                         return CONVERT_M_MG_VTF16E14_X(
 276                                                 DATA_BYTES, MAGN_EXPONENT, val);
 277
 278                                 case 1:
 279                                         return CONVERT_M_MG_VTF16E14_Y(
 280                                                 DATA_BYTES, MAGN_EXPONENT, val);
 281
 282                                 case 2:
 283                                         return CONVERT_M_MG_VTF16E14_Z(
 284                                                 DATA_BYTES, MAGN_EXPONENT, val);
 285                         }
 286                         break;
 287
 288                 case SENSOR_TYPE_ORIENTATION:
 289                         return convert_from_vtf_format(DATA_BYTES, INC_EXPONENT,
 290                                 val);
 291
 292                 case SENSOR_TYPE_ROTATION_VECTOR:
 293                         return convert_from_vtf_format(DATA_BYTES, ROT_EXPONENT,
 294                                 val);
 295         }
 296
 297         return 0;
 298 }
 299
 300
 301 void select_transform (int s)
 302 {
 303         char prop_name[PROP_NAME_MAX];
 304         char prop_val[PROP_VALUE_MAX];
 305         int i                   = sensor_info[s].catalog_index;
 306         const char *prefix      = sensor_catalog[i].tag;
 307
 308         sprintf(prop_name, PROP_BASE, prefix, "transform");
 309
 310         if (property_get(prop_name, prop_val, "")) {
 311                 if (!strcmp(prop_val, "ISH")) {
 312                         ALOGI(  "Using Intel Sensor Hub semantics on %s\n",
 313                                 sensor_info[s].friendly_name);
 314
 315                         sensor_info[s].ops.transform = transform_sample_ISH;
 316                         sensor_info[s].ops.finalize = finalize_sample_ISH;
 317                         return;
 318                 }
 319         }
 320
 321         sensor_info[s].ops.transform = transform_sample_default;
 322         sensor_info[s].ops.finalize = finalize_sample_default;
 323 }
 324
 325
 326 float acquire_immediate_value(int s, int c)
 327 {
 328         char sysfs_path[PATH_MAX];
 329         float val;
 330         int ret;
 331         int dev_num = sensor_info[s].dev_num;
 332         int i = sensor_info[s].catalog_index;
 333         const char* raw_path = sensor_catalog[i].channel[c].raw_path;
 334         const char* input_path = sensor_catalog[i].channel[c].input_path;
 335         float scale = sensor_info[s].scale;
 336         float offset = sensor_info[s].offset;
 337
 338         /* Acquire a sample value for sensor s / channel c through sysfs */
 339
 340         if (input_path[0]) {
 341                 sprintf(sysfs_path, BASE_PATH "%s", dev_num, input_path);
 342                 ret = sysfs_read_float(sysfs_path, &val);
 343
 344                 if (!ret) {
 345                         return val;
 346                 }
 347         };
 348
 349         if (!raw_path[0])
 350                 return 0;
 351
 352         sprintf(sysfs_path, BASE_PATH "%s", dev_num, raw_path);
 353         ret = sysfs_read_float(sysfs_path, &val);
 354
 355         if (ret == -1)
 356                 return 0;
 357
 358         return (val + offset) * scale;
 359 }