Re: [PATCH v4 04/20] dt-bindings: qcom-bam: Convert binding to YAML

[Vladimir Zapolskiy <vladimir.zapolskiy@linaro.org>]

Hi Bhupesh,

On 10/13/21 1:55 PM, Bhupesh Sharma wrote:
> Convert Qualcomm BAM DMA devicetree binding to YAML.
> 
> Cc: Thara Gopinath <thara.gopinath@linaro.org>
> Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
> Cc: Rob Herring <robh+dt@kernel.org>
> Signed-off-by: Bhupesh Sharma <bhupesh.sharma@linaro.org>
> ---
>   .../devicetree/bindings/dma/qcom_bam_dma.txt  | 50 -----------
>   .../devicetree/bindings/dma/qcom_bam_dma.yaml | 89 +++++++++++++++++++
>   2 files changed, 89 insertions(+), 50 deletions(-)
>   delete mode 100644 Documentation/devicetree/bindings/dma/qcom_bam_dma.txt
>   create mode 100644 Documentation/devicetree/bindings/dma/qcom_bam_dma.yaml
> 
> diff --git a/Documentation/devicetree/bindings/dma/qcom_bam_dma.txt b/Documentation/devicetree/bindings/dma/qcom_bam_dma.txt
> deleted file mode 100644
> index cf5b9e44432c..000000000000
> --- a/Documentation/devicetree/bindings/dma/qcom_bam_dma.txt
> +++ /dev/null
> @@ -1,50 +0,0 @@
> -QCOM BAM DMA controller
> -
> -Required properties:
> -- compatible: must be one of the following:
> - * "qcom,bam-v1.4.0" for MSM8974, APQ8074 and APQ8084
> - * "qcom,bam-v1.3.0" for APQ8064, IPQ8064 and MSM8960
> - * "qcom,bam-v1.7.0" for MSM8916
> -- reg: Address range for DMA registers
> -- interrupts: Should contain the one interrupt shared by all channels
> -- #dma-cells: must be <1>, the cell in the dmas property of the client device
> -  represents the channel number
> -- clocks: required clock
> -- clock-names: must contain "bam_clk" entry
> -- qcom,ee : indicates the active Execution Environment identifier (0-7) used in
> -  the secure world.
> -- qcom,controlled-remotely : optional, indicates that the bam is controlled by
> -  remote proccessor i.e. execution environment.
> -- num-channels : optional, indicates supported number of DMA channels in a
> -  remotely controlled bam.
> -- qcom,num-ees : optional, indicates supported number of Execution Environments
> -  in a remotely controlled bam.
> -
> -Example:
> -
> -	uart-bam: dma@f9984000 = {
> -		compatible = "qcom,bam-v1.4.0";
> -		reg = <0xf9984000 0x15000>;
> -		interrupts = <0 94 0>;
> -		clocks = <&gcc GCC_BAM_DMA_AHB_CLK>;
> -		clock-names = "bam_clk";
> -		#dma-cells = <1>;
> -		qcom,ee = <0>;
> -	};
> -
> -DMA clients must use the format described in the dma.txt file, using a two cell
> -specifier for each channel.
> -
> -Example:
> -	serial@f991e000 {
> -		compatible = "qcom,msm-uart";
> -		reg = <0xf991e000 0x1000>
> -			<0xf9944000 0x19000>;
> -		interrupts = <0 108 0>;
> -		clocks = <&gcc GCC_BLSP1_UART2_APPS_CLK>,
> -			<&gcc GCC_BLSP1_AHB_CLK>;
> -		clock-names = "core", "iface";
> -
> -		dmas = <&uart-bam 0>, <&uart-bam 1>;
> -		dma-names = "rx", "tx";
> -	};
> diff --git a/Documentation/devicetree/bindings/dma/qcom_bam_dma.yaml b/Documentation/devicetree/bindings/dma/qcom_bam_dma.yaml
> new file mode 100644
> index 000000000000..32b47e3b7769
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/dma/qcom_bam_dma.yaml
> @@ -0,0 +1,89 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/dma/qcom_bam_dma.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: QCOM BAM DMA controller binding
> +
> +maintainers:
> +  - Bhupesh Sharma <bhupesh.sharma@linaro.org>
> +
> +description: |
> +  This document defines the binding for the BAM DMA controller
> +  found on Qualcomm parts.
> +
> +allOf:
> +  - $ref: "dma-controller.yaml#"
> +
> +properties:
> +  compatible:
> +    enum:
> +      - qcom,bam-v1.4.0 # for MSM8974, APQ8074 and APQ8084
> +      - qcom,bam-v1.3.0 # for APQ8064, IPQ8064 and MSM8960
> +      - qcom,bam-v1.7.0 # for MSM8916

would it be better to sort the list above by IP version?

> +
> +  reg:
> +    maxItems: 1
> +
> +  clocks:
> +    maxItems: 1
> +
> +  clock-names:
> +    const: bam_clk
> +
> +  interrupts:
> +    minItems: 1
> +    maxItems: 31
> +
> +  num-channels:
> +    maximum: 31
> +    description: |
> +      Indicates supported number of DMA channels in a remotely controlled bam.

A comment about YAML specifics, I'm not sure, if it makes sense to set a control
to enable literal style of the given multiline description, since it is a one-liner.

My main observation though is that all actually multi-line descriptions in the
schema are different and of the folded style ("pipe" symbol is not set).

Probably it's good enough just to remove the "pipe" above.

> +
> +  "#dma-cells":
> +    const: 1
> +    description: The single cell represents the channel index.
> +
> +  qcom,ee:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    description:
> +      Indicates the active Execution Environment identifier (0-7)
> +      used in the secure world.

Would it make sense to add here

   minimum: 0
   maximum: 7

?

> +
> +  qcom,controlled-remotely:
> +    $ref: /schemas/types.yaml#/definitions/flag
> +    description:
> +      Indicates that the bam is controlled by remote proccessor i.e.
> +      execution environment.
> +
> +  qcom,num-ees:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    minimum: 0
> +    maximum: 31
> +    default: 2
> +    description:
> +      Indicates supported number of Execution Environments in a
> +      remotely controlled bam.
> +
> +required:
> +  - compatible
> +  - reg
> +  - interrupts
> +  - "#dma-cells"
> +  - qcom,ee
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/clock/qcom,gcc-msm8974.h>
> +    dma-controller@f9984000 {
> +        compatible = "qcom,bam-v1.4.0";
> +        reg = <0xf9984000 0x15000>;
> +        interrupts = <0 94 0>;
> +        clocks = <&gcc GCC_BAM_DMA_AHB_CLK>;
> +        clock-names = "bam_clk";
> +        #dma-cells = <1>;
> +        qcom,ee = <0>;
> +    };
> 

--
Best wishes,
Vladimir