Add bindings documentation for the new Atmel DMA controller (XDMAC)
introduced with SAMA5D4.
Signed-off-by: Ludovic Desroches <ludovic.desroches@xxxxxxxxx>
---
.../devicetree/bindings/dma/atmel-xdma.txt | 50 ++++++++++++++++++++++
1 file changed, 50 insertions(+)
create mode 100644 Documentation/devicetree/bindings/dma/atmel-xdma.txt
diff --git a/Documentation/devicetree/bindings/dma/atmel-xdma.txt b/Documentation/devicetree/bindings/dma/atmel-xdma.txt
new file mode 100644
index 0000000..ae587ad
--- /dev/null
+++ b/Documentation/devicetree/bindings/dma/atmel-xdma.txt
@@ -0,0 +1,50 @@
+* Atmel Extensible Direct Memory Access Controller (XDMAC)
+
+* XDMA Controller
+Required properties:
+- compatible: Should be "atmel,<chip>-dma".
+ <chip> compatible description:
+ - sama5d4: first SoC adding the XDMAC
+- 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.
+ - The 1st cell specifies the memory interface (16 most significant bits) and
+ the peripheral interface (16 less significant bits) to use.
+ - The 2nd cell specifies the channel configuration register:
+ - bit 30-24: PERID, peripheral identifier.
+
+Example:
+
+dma1: dma-controller@f0004000 {
+ compatible = "atmel,sama5d4-dma";
+ reg = <0xf0004000 0x200>;
+ interrupts = <50 4 0>;
+ #dma-cells = <2>;
+};
+
+
+* DMA clients
+DMA clients connected to the Atmel XDMA controller must use the format
+described in the dma.txt file, using a two-cell specifier for each channel.
+The three 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@f8024000 {
+ compatible = "atmel,at91sam9x5-i2c";
+ reg = <0xf8024000 0x4000>;
+ interrupts = <34 4 6>;
+ dmas = <&dma1
+ (AT91_XDMAC_DT_MEM_IF(0) | AT91_XDMAC_DT_PER_IF(1))
+ AT91_XDMAC_DT_PERID(6)>,
+ <&dma1
+ (AT91_XDMAC_DT_MEM_IF(0) | AT91_XDMAC_DT_PER_IF(1))
+ AT91_XDMAC_DT_PERID(7)>;
+ dma-names = "tx", "rx";
+};
--
2.0.3
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