[PATCH v7 2/3] ARM: dts: at_xdmac: add bindings documentation
From: Ludovic Desroches <hidden>
Date: 2014-10-22 15:22:19
Also in:
linux-devicetree
Subsystem:
dma generic offload engine subsystem, open firmware and flattened device tree bindings, the rest · Maintainers:
Vinod Koul, Rob Herring, Krzysztof Kozlowski, Conor Dooley, Linus Torvalds
Add bindings documentation for the new Atmel DMA controller (XDMAC) introduced with SAMA5D4. Signed-off-by: Ludovic Desroches <redacted> Acked-by: Nicolas Ferre <redacted> --- .../devicetree/bindings/dma/atmel-xdma.txt | 54 ++++++++++++++++++++++ 1 file changed, 54 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..e75c128
--- /dev/null
+++ b/Documentation/devicetree/bindings/dma/atmel-xdma.txt@@ -0,0 +1,54 @@ +* 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 <1>, used to represent the number of integer cells in +the dmas property of client devices. + - The 1st cell specifies the channel configuration register: + - bit 13: SIF, source interface identifier, used to get the memory + interface identifier, + - bit 14: DIF, destination interface identifier, used to get the peripheral + interface identifier, + - bit 30-24: PERID, peripheral identifier. + +Example: + +dma1: dma-controller at 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 one-cell specifier for each channel. +The two cells in order are: +1. A phandle pointing to the DMA controller. +2. Channel configuration register. Configurable fields are: + - bit 13: SIF, source interface identifier, used to get the memory + interface identifier, + - bit 14: DIF, destination interface identifier, used to get the peripheral + interface identifier, + - bit 30-24: PERID, peripheral identifier. + +Example: + +i2c2: i2c at 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"; +};
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2.0.3