STM32_DMA_FIFO_THRESHOLD_NONE
if (fifoth != STM32_DMA_FIFO_THRESHOLD_NONE)
chan->threshold = STM32_DMA_FIFO_THRESHOLD_NONE;
if (threshold == STM32_DMA_FIFO_THRESHOLD_NONE)
if (threshold == STM32_DMA_FIFO_THRESHOLD_NONE)
if (fifoth != STM32_DMA_FIFO_THRESHOLD_NONE)