On Fri, Sep 14, 2012 at 05:41:56PM -0500, Jon Hunter wrote:
...
Typo nits in the binding examples below...
> Documentation/devicetree/bindings/dma/dma.txt | 81 +++++++++
> drivers/of/Makefile | 2 +-
> drivers/of/dma.c | 219 +++++++++++++++++++++++++
> include/linux/of_dma.h | 45 +++++
> 4 files changed, 346 insertions(+), 1 deletion(-)
> create mode 100644 Documentation/devicetree/bindings/dma/dma.txt
> create mode 100644 drivers/of/dma.c
> create mode 100644 include/linux/of_dma.h
>
> diff --git a/Documentation/devicetree/bindings/dma/dma.txt b/Documentation/devicetree/bindings/dma/dma.txt
> new file mode 100644
> index 0000000..a4f59a5
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/dma/dma.txt
> @@ -0,0 +1,81 @@
> +* Generic DMA Controller and DMA request bindings
> +
> +Generic binding to provide a way for a driver using DMA Engine to retrieve the
> +DMA request or channel information that goes from a hardware device to a DMA
> +controller.
> +
> +
> +* DMA controller
> +
> +Required property:
> +- #dma-cells: Must be at least 1. Used to provide DMA controller
> + specific information. See DMA client binding below for
> + more details.
> +
> +Optional properties:
> +- #dma-channels: Number of DMA channels supported by the controller.
> +- #dma-requests: Number of DMA requests signals supported by the
> + controller.
> +
> +Example:
> +
> + dma: dma@48000000 {
> + compatible = "ti,omap-sdma"
; here
> + reg = <0x48000000 0x1000>;
> + interrupts = <0 12 0x4
> + 0 13 0x4
> + 0 14 0x4
> + 0 15 0x4>;
> + #dma-cells = <1>;
> + #dma-channels = <32>;
> + #dma-requests = <127>;
> + };
> +
> +
> +* DMA client
> +
> +Client drivers should specify the DMA property using a phandle to the controller
> +followed by DMA controller specific data.
> +
> +Required property:
> +- dmas: List of one or more DMA specifiers, each consisting of
> + - A phandle pointing to DMA controller node
> + - A number of integer cells, as determined by the
> + #dma-cells property in the node referenced by phandle
> + containing DMA controller specific information. This
> + typically contains a DMA request line number or a
> + channel number, but can contain any data that is used
> + required for configuring a channel.
> +- dma-names: Contains one identifier string for each DMA specifier in
> + the dmas property. The specific strings that can be used
> + are defined in the binding of the DMA client device.
> + Multiple DMA specifiers can be used to represent
> + alternatives and in this case the dma-names for those
> + DMA specifiers must be identical (see examples).
> +
> +Examples:
> +
> +1. A device with one DMA read channel, one DMA write channel:
> +
> + i2c1: i2c@1 {
> + ...
> + dmas = <&dma 2 /* read channel */
> + &dma 3>; /* write channel */
> + dma-names = "rx", "tx"
; here too
> + ...
> + };
> +
> +2. A single read-write channel with three alternative DMA controllers:
> +
> + dmas = <&dma1 5
> + &dma2 7
> + &dma3 2>;
> + dma-names = "rx-tx", "rx-tx", "rx-tx"
again ;
> +
> +3. A device with three channels, one of which has two alternatives:
> +
> + dmas = <&dma1 2 /* read channel */
> + &dma1 3 /* write channel */
> + &dma2 0 /* error read */
> + &dma3 0>; /* alternative error read */
> + dma-names = "rx", "tx", "error", "error";
Patch for these posted separately.
-Matt
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