Re: [PATCH 2/2] dmaengine: msm_bam_dma: Add device tree binding

From: Kumar Gala
Date: Fri Oct 25 2013 - 17:31:32 EST



On Oct 25, 2013, at 3:24 PM, Andy Gross wrote:

> Add device tree probe support for the MSM BAM DMA driver.
>

The description here isn't correct, its the binding not probe ;).

> Signed-off-by: Andy Gross <agross@xxxxxxxxxxxxxx>
> ---
> .../devicetree/bindings/dma/msm_bam_dma.txt | 49 ++++++++++++++++++++
> 1 file changed, 49 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/dma/msm_bam_dma.txt
>
> diff --git a/Documentation/devicetree/bindings/dma/msm_bam_dma.txt b/Documentation/devicetree/bindings/dma/msm_bam_dma.txt
> new file mode 100644
> index 0000000..fe3ed8f
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/dma/msm_bam_dma.txt
> @@ -0,0 +1,49 @@
> +MSM BAM DMA controller
> +
> +Required properties:
> +- compatible: Should be "qcom,bam"
> +- reg: Address range for DMA registers
> +- interrupts: single interrupt for this controller
> +- #dma-cells: must be <3>
> +- clocks: required clock
> +- clock-names: name of clock
> +
> +Example:
> +
> + dma0: dma@f9984000 = {
> + compatible = "qcom,bam";
> + reg = <0xf9984000 0x15000>;
> + interrupts = <0 94 0>;
> + clocks = <&bam_dma_ahb_cxc>;
> + clock-names = "bam_clk";
> + #dma-cells = <3>;
> + };
> +
> +Client:
> +Required properties:
> +- dmas: List of dma channel requests
> +- dma-names: Names of aforementioned requested channels
> +
> +Clients must use the format described in the dma.txt file, using a four cell
> +specifier for each channel.
> +
> +The four cells in order are:
> + 1. A phandle pointing to the DMA controller
> + 2. The channel number
> + 3. The execution environment value for this channel.

This needs further explanation on what the value means.

> + 4. Direction of the fixed unidirectional channel
> + 0 - Memory to Device
> + 1 - Device to Memory
> +
> +Example:
> + serial@f991e000 {
> + compatible = "qcom,msm-uart";
> + reg = <0xf991e000 0x1000>
> + <0xf9944000 0x19000>;
> + interrupts = <0 108 0>;
> + clocks = <&blsp1_uart2_apps_cxc>, <&blsp1_ahb_cxc>;
> + clock-names = "gsbi_uart_clk", "gsbi_pclk";
> +
> + dmas = <&dma0 0 0 1>, <&dma0 1 0 0>;
> + dma-names = "rx", "tx";
> + };
> --
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