[PATCH v2 2/2] ARM: dts: at_xdmac: add bindings documentation
From: mark.rutland@arm.com (Mark Rutland)
Date: 2014-07-04 08:58:34
Also in:
linux-devicetree
On Fri, Jul 04, 2014 at 08:36:10AM +0100, Ludovic Desroches wrote:
quoted hunk
Add bindings documentation for the new Atmel DMA controller (XDMAC) introduced with SAMA5D4. Signed-off-by: Ludovic Desroches <redacted> --- .../devicetree/bindings/dma/atmel-xdma.txt | 39 ++++++++++++++++++++ 1 file changed, 39 insertions(+) create mode 100644 Documentation/devicetree/bindings/dma/atmel-xdma.txtdiff --git a/Documentation/devicetree/bindings/dma/atmel-xdma.txt b/Documentation/devicetree/bindings/dma/atmel-xdma.txt new file mode 100644 index 0000000..1e09fda --- /dev/null +++ b/Documentation/devicetree/bindings/dma/atmel-xdma.txt@@ -0,0 +1,39 @@ +* Atmel Extensible Direct Memory Access Controller (XDMAC) + +Required properties: +- compatible: Should be "atmel,<chip>-dma". +- reg: Should contain DMA registers location and length. +- interrupts: Should contain DMA interrupt. +- #dma-cells: Must be <2>, used to represent the number of integer cells in +the dmas property of client devices.
Could you please move the description of the two cells in the dma-specifier here? It makes it far easier to read the binding. Cheers, Mark.
+
+Example:
+
+dma1: dma-controller at f0004000 {
+ compatible = "atmel,sama5d4-dma";
+ reg = <0xf0004000 0x200>;
+ interrupts = <50 4 0>;
+ #dma-cells = <2>;
+};
+
+DMA clients connected to the Atmel XDMA controller must use the format
+described in the dma.txt file, using a three-cell specifier for each channel:
+a phandle plus two integer cells.
+The two cells in order are:
+
+1. A phandle pointing to the DMA controller.
+2. The memory interface (16 most significant bits), the peripheral interface
+(16 less significant bits).
+3. Channel configuration register. Configurable fields are:
+ - bit 30-24: PERID, peripheral identifier.
+
+Example:
+
+i2c2: i2c at f8024000 {
+ compatible = "atmel,at91sam9x5-i2c";
+ reg = <0xf8024000 0x4000>;
+ interrupts = <34 4 6>;
+ dmas = <&dma0 0x00000001 0x06000000>,
+ <&dma0 0x00000001 0x07000000>;
+ dma-names = "tx", "rx";
+};
--
1.7.9.5
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