The spi_setcfg() function sets the configuration for a specific device on the SPI bus. The prototype for this function is:
int spi_setcfg( int fd,
                uint32_t device,
                spi_cfg_t *cfg );
The arguments are:
typedef struct {
    uint32_t    mode;
    uint32_t    clock_rate;
} spi_cfg_t;
  
  The possible mode settings are defined in <hw/spi-master.h>.
This function returns EOK if the configuration is successful.