[PATCH V4 1/2] of: Add generic device tree DMA helpers
Stephen Warren
swarren at wwwdotorg.org
Sat Sep 15 02:28:57 EST 2012
On 09/13/2012 04:00 PM, Jon Hunter wrote:
> This is based upon the work by Benoit Cousson [1] and Nicolas Ferre [2]
> to add some basic helpers to retrieve a DMA controller device_node and the
> DMA request/channel information.
> diff --git a/Documentation/devicetree/bindings/dma/dma.txt b/Documentation/devicetree/bindings/dma/dma.txt
> +* 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
...
> +* 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 single integer cell 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.
"A single integer cell" doesn't sound correct; shouldn't this be
something like "a number of integer cells, as determined by the
#dma-cells property in the node referenced by phandle"?
> +- 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.
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