SPRD_SPI_TX
struct dma_chan *dma_chan = ss->dma.dma_chan[SPRD_SPI_TX];
ss->dma.dma_chan[SPRD_SPI_TX] = dma_request_chan(ss->dev, "tx_chn");
if (IS_ERR_OR_NULL(ss->dma.dma_chan[SPRD_SPI_TX])) {
return dev_err_probe(ss->dev, PTR_ERR(ss->dma.dma_chan[SPRD_SPI_TX]),
if (ss->dma.dma_chan[SPRD_SPI_TX])
dma_release_channel(ss->dma.dma_chan[SPRD_SPI_TX]);