AD74115_FRAME_SIZE
u8 reg_tx_buf[AD74115_FRAME_SIZE] __aligned(IIO_DMA_MINALIGN);
u8 reg_rx_buf[AD74115_FRAME_SIZE];
u8 adc_samples_tx_buf[AD74115_FRAME_SIZE * AD74115_ADC_CH_NUM];
u8 adc_samples_rx_buf[AD74115_FRAME_SIZE * AD74115_ADC_CH_NUM];
return spi_write(st->spi, st->reg_tx_buf, AD74115_FRAME_SIZE);
xfer->len = AD74115_FRAME_SIZE;
tx_buf += AD74115_FRAME_SIZE;
rx_buf += AD74115_FRAME_SIZE;
xfer->len = AD74115_FRAME_SIZE;