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

From: Kumar Gala <galak@codeaurora.org>
To: Andy Gross <agross@codeaurora.org>
Cc: Vinod Koul <vinod.koul@intel.com>,
	linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org,
	Dan Williams <dan.j.williams@intel.com>,
	David Brown <davidb@codeaurora.org>,
	Bryan Huntsman <bryanh@codeaurora.org>
Subject: Re: [PATCH 2/2] dmaengine: msm_bam_dma: Add device tree binding
Date: Fri, 25 Oct 2013 16:31:42 -0500	[thread overview]
Message-ID: <87302369-689E-476F-8B2D-B178CE3C0D48@codeaurora.org> (raw)
In-Reply-To: <1382732643-8184-3-git-send-email-agross@codeaurora.org>

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@codeaurora.org>
> ---
> .../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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-- 
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation