LEDC_FIFO_DEPTH
burst = min(length, LEDC_FIFO_DEPTH - fifo_used);
if (priv->dma_chan && length > LEDC_FIFO_DEPTH) {
FIELD_PREP_CONST(LEDC_DMA_CTRL_REG_FIFO_TRIG_LEVEL, LEDC_FIFO_DEPTH / 2);
dma_cfg.dst_maxburst = LEDC_FIFO_DEPTH / 2;