SSI_DMA_TX_BUSY
if (!(state & SSI_DMA_TX_BUSY))
int state = atomic_fetch_andnot(SSI_DMA_TX_BUSY, &priv->dma_busy);
atomic_or(SSI_DMA_TX_BUSY, &priv->dma_busy);
if (atomic_read(&priv->dma_busy) & SSI_DMA_TX_BUSY) {
atomic_andnot(SSI_DMA_TX_BUSY, &priv->dma_busy);