K1_SPI_THRESH
val = FIELD_PREP(FIFO_RFT_MASK, K1_SPI_THRESH - 1);
val |= FIELD_PREP(FIFO_TFT_MASK, K1_SPI_THRESH - 1);
burst_size = K1_SPI_THRESH * spi_bpw_to_bytes(transfer->bits_per_word);
u32 burst_size = K1_SPI_THRESH * drv_data->bytes;
count = min3(count, K1_SPI_THRESH, drv_data->tx_resid / drv_data->bytes);