XTFPGA_I2S_FIFO_SIZE
i2s->tx_fifo_low = XTFPGA_I2S_FIFO_SIZE / 2;
.period_bytes_max = XTFPGA_I2S_FIFO_SIZE / 2 * 8,
.periods_max = XTFPGA_I2S_FIFO_SIZE * 8 / 2,
.buffer_bytes_max = XTFPGA_I2S_FIFO_SIZE * 8,