dt-overlay to enable dma for spi driver

Signed-off-by: Martin Sperl <[email protected]>

Author: msperl

arch/arm/boot/dts/overlays/Makefile

@@ -45,6 +45,7 @@ dtb-$(RPI_DT_OVERLAYS) += rpi-sense-overlay.dtb
 dtb-$(RPI_DT_OVERLAYS) += sdhost-overlay.dtb
 dtb-$(RPI_DT_OVERLAYS) += spi-bcm2708-overlay.dtb
 dtb-$(RPI_DT_OVERLAYS) += spi-bcm2835-overlay.dtb
+dtb-$(RPI_DT_OVERLAYS) += spi-dma-overlay.dtb
 dtb-$(RPI_DT_OVERLAYS) += tinylcd35-overlay.dtb
 dtb-$(RPI_DT_OVERLAYS) += uart1-overlay.dtb
 dtb-$(RPI_DT_OVERLAYS) += vga666-overlay.dtb

arch/arm/boot/dts/overlays/spi-dma-overlay.dts

@@ -0,0 +1,20 @@
+/*
+ * Device tree overlay for spi-bcm2835 to allow dma
+ */
+
+/dts-v1/;
+/plugin/;
+
+/ {
+	compatible = "brcm,bcm2835", "brcm,bcm2836", "brcm,bcm2708", "brcm,bcm2709";
+
+	fragment@0 {
+		target = <&spi0>;
+		__overlay__ {
+			#address-cells = <1>;
+			#size-cells = <0>;
+			dmas = <&dma 6>, <&dma 7>;
+			dma-names = "tx", "rx";
+		};
+	};
+ };