quoted

+static int fsl_sai_probe(struct platform_device *pdev) {

[...]

quoted

+
+	sai->dma_params_rx.addr = res->start + SAI_RDR;
+	sai->dma_params_rx.maxburst = 6;
+	index = of_property_match_string(np, "dma-names", "rx");
+	ret = of_parse_phandle_with_args(np, "dmas", "#dma-cells", index,
+				&dma_args);
+	if (ret)
+		return ret;
+	sai->dma_params_rx.slave_id = dma_args.args[1];
+
+	sai->dma_params_tx.addr = res->start + SAI_TDR;
+	sai->dma_params_tx.maxburst = 6;
+	index = of_property_match_string(np, "dma-names", "tx");
+	ret = of_parse_phandle_with_args(np, "dmas", "#dma-cells", index,
+				&dma_args);
+	if (ret)
+		return ret;
+	sai->dma_params_tx.slave_id = dma_args.args[1];

The driver should not have to manually parse the dma devicetree
properties, this is something that should be handled by the dma engine
driver.

Yes, the dma engine interface has already parsed the slave_id while
the dma customer requesting one dma channel.

Though this also could be a way to pass the slave_id to dma driver, but the 
dma driver uses the way while requesting dma channels.

So I'll drop this code later.