spi: rspi: Add DT support to DMA setup

Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NMark Brown <broonie@linaro.org>

Documentation/devicetree/bindings/spi/spi-rspi.txt

@@ -30,6 +30,9 @@ Required properties:
 
 Optional properties:
 - clocks           : Must contain a reference to the functional clock.
+- dmas             : Must contain a list of two references to DMA specifiers,
+		     one for transmission, and one for reception.
+- dma-names        : Must contain a list of two DMA names, "tx" and "rx".
 
 Pinctrl properties might be needed, too.  See
 Documentation/devicetree/bindings/pinctrl/renesas,*.
@@ -58,4 +61,6 @@ Examples:
 		num-cs = <1>;
 		#address-cells = <1>;
 		#size-cells = <0>;
+		dmas = <&dmac0 0x17>, <&dmac0 0x18>;
+		dma-names = "tx", "rx";
 	};

drivers/spi/spi-rspi.c

@@ -909,10 +909,11 @@ static struct dma_chan *rspi_request_dma_chan(struct device *dev,
 	dma_cap_zero(mask);
 	dma_cap_set(DMA_SLAVE, mask);
 
-	chan = dma_request_channel(mask, shdma_chan_filter,
-				   (void *)(unsigned long)id);
+	chan = dma_request_slave_channel_compat(mask, shdma_chan_filter,
+				(void *)(unsigned long)id, dev,
+				dir == DMA_MEM_TO_DEV ? "tx" : "rx");
 	if (!chan) {
-		dev_warn(dev, "dma_request_channel failed\n");
+		dev_warn(dev, "dma_request_slave_channel_compat failed\n");
 		return NULL;
 	}
 
@@ -941,22 +942,30 @@ static int rspi_request_dma(struct device *dev, struct spi_master *master,
 			    const struct resource *res)
 {
 	const struct rspi_plat_data *rspi_pd = dev_get_platdata(dev);
+	unsigned int dma_tx_id, dma_rx_id;
+
+	if (dev->of_node) {
+		/* In the OF case we will get the slave IDs from the DT */
+		dma_tx_id = 0;
+		dma_rx_id = 0;
+	} else if (rspi_pd && rspi_pd->dma_tx_id && rspi_pd->dma_rx_id) {
+		dma_tx_id = rspi_pd->dma_tx_id;
+		dma_rx_id = rspi_pd->dma_rx_id;
+	} else {
+		/* The driver assumes no error. */
+		return 0;
+	}
 
-	if (!rspi_pd || !rspi_pd->dma_rx_id || !rspi_pd->dma_tx_id)
-		return 0;	/* The driver assumes no error. */
-
-	master->dma_rx = rspi_request_dma_chan(dev, DMA_DEV_TO_MEM,
-					       rspi_pd->dma_rx_id,
+	master->dma_tx = rspi_request_dma_chan(dev, DMA_MEM_TO_DEV, dma_tx_id,
 					       res->start + RSPI_SPDR);
-	if (!master->dma_rx)
+	if (!master->dma_tx)
 		return -ENODEV;
 
-	master->dma_tx = rspi_request_dma_chan(dev, DMA_MEM_TO_DEV,
-					       rspi_pd->dma_tx_id,
+	master->dma_rx = rspi_request_dma_chan(dev, DMA_DEV_TO_MEM, dma_rx_id,
 					       res->start + RSPI_SPDR);
-	if (!master->dma_tx) {
-		dma_release_channel(master->dma_rx);
-		master->dma_rx = NULL;
+	if (!master->dma_rx) {
+		dma_release_channel(master->dma_tx);
+		master->dma_tx = NULL;
 		return -ENODEV;
 	}