On Wed, Mar 12, 2014 at 11:47:54AM +0000, Alexander Popov wrote:
> From: Gerhard Sittig <gsi@xxxxxxx>
>
> introduce a device tree binding document for the MPC512x DMA controller
>
> Signed-off-by: Gerhard Sittig <gsi@xxxxxxx>
> [ a13xp0p0v88@xxxxxxxxx: turn this into a separate patch ]
> ---
> .../devicetree/bindings/dma/mpc512x-dma.txt | 55 ++++++++++++++++++++++
> 1 file changed, 55 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/dma/mpc512x-dma.txt
>
> diff --git a/Documentation/devicetree/bindings/dma/mpc512x-dma.txt b/Documentation/devicetree/bindings/dma/mpc512x-dma.txt
> new file mode 100644
> index 0000000..a4867d5
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/dma/mpc512x-dma.txt
> @@ -0,0 +1,55 @@
> +* Freescale MPC512x DMA Controller
> +
> +The DMA controller in the Freescale MPC512x SoC can move blocks of
> +memory contents between memory and peripherals or memory to memory.
> +
> +Refer to the "Generic DMA Controller and DMA request bindings" description
> +in the dma.txt file for a more detailled discussion of the binding. The
> +MPC512x DMA engine binding follows the common scheme, but doesn't provide
> +support for the optional channels and requests counters (those values are
> +derived from the detected hardware features) and has a fixed client
> +specifier length of 1 integer cell (the value is the DMA channel, since
> +the DMA controller uses a fixed assignment of request lines per channel).
> +
> +
> +DMA controller node properties:
> +
> +Required properties:
> +- compatible: should be "fsl,mpc5121-dma"
> +- reg: address and size of the DMA controller's register set
> +- interrupts: interrupt spec for the DMA controller
> +
> +Optional properties:
> +- #dma-cells: must be <1>, describes the number of integer cells
> + needed to specify the 'dmas' property in client nodes,
> + strongly recommended since common client helper code
> + uses this property
Describe what you expect this cell to contain, not the #dma-cells
binding in general. The DMA bindings already cover that.
What are valid value that clients may use, and what do they mean?
> +
> +Example:
> +
> + dma0: dma@14000 {
> + compatible = "fsl,mpc5121-dma";
> + reg = <0x14000 0x1800>;
> + interrupts = <65 0x8>;
> + #dma-cells = <1>;
> + };
> +
> +
> +Client node properties:
> +
> +Required properties:
> +- dmas: list of DMA specifiers, consisting each of a handle
> + for the DMA controller and integer cells to specify
> + the channel used within the DMA controller
> +- dma-names: list of identifier strings for the DMA specifiers,
> + client device driver code uses these strings to
> + have DMA channels looked up at the controller
List the exact names you expect, or the dma-names property is useless.
Thanks,
Mark.
> +
> +Example:
> +
> + sdhc@1500 {
> + compatible = "fsl,mpc5121-sdhc";
> + /* ... */
> + dmas = <&dma0 30>;
> + dma-names = "rx-tx";
> + };
> --
> 1.8.4.2
>
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