typedef struct { CTL_SPI_DEVICE_t *spi; CTL_I2C_BUS_t *i2c; void *v; } CTL_TRANSPORT_BUS_t;
MEMS digital sensors are typically on SPI or I2C buses and have a register interface. But, of course, there could be other ways to sample those registers. This structure provides private storage for the transport to run over SPI and I2C buses.