// Sends bytes over SPI channel and returns []byte response
func (spi *SPIDevice) Send(bytes_to_send [3]byte) ([]byte, error) {
wBuffer := bytes_to_send
rBuffer := [3]byte{}
// generates message
transfer := SPI_IOC_TRANSFER{}
transfer.txBuf = uint64(uintptr(unsafe.Pointer(&wBuffer)))
transfer.rxBuf = uint64(uintptr(unsafe.Pointer(&rBuffer)))
transfer.length = uint32(unsafe.Sizeof(wBuffer))
transfer.delayUsecs = SPI_DELAY
transfer.bitsPerWord = spi.bpw
transfer.speedHz = spi.speed
// sends message over SPI
err := ioctl.IOCTL(spi.file.Fd(), SPI_IOC_MESSAGE(1), uintptr(unsafe.Pointer(&transfer)))
if err != nil {
return nil, fmt.Errorf("Error on sending: %s\n", err)
}
// generates a valid response
ret := make([]byte, unsafe.Sizeof(rBuffer))
for i := range ret {
ret[i] = rBuffer[i]
}
return ret, nil
}
func (spi *SPIDevice) SetMode(mode uint8) error {
spi.mode = mode
err := ioctl.IOCTL(spi.file.Fd(), SPI_IOC_WR_MODE(), uintptr(unsafe.Pointer(&mode)))
if err != nil {
return fmt.Errorf("Error setting mode: %s\n", err)
}
return nil
}
func (spi *SPIDevice) SetSpeed(speed uint32) error {
spi.speed = speed
err := ioctl.IOCTL(spi.file.Fd(), SPI_IOC_WR_MAX_SPEED_HZ(), uintptr(unsafe.Pointer(&speed)))
if err != nil {
return fmt.Errorf("Error setting speed: %s\n", err)
}
return nil
}
func (spi *SPIDevice) SetBitsPerWord(bpw uint8) error {
spi.bpw = bpw
err := ioctl.IOCTL(spi.file.Fd(), SPI_IOC_WR_BITS_PER_WORD(), uintptr(unsafe.Pointer(&bpw)))
if err != nil {
return fmt.Errorf("Error setting bits per word: %s\n", err)
}
return nil
}