Re: [PATCH v1 4/6] dt-bindings: memory: tegra20: mc: Convert to schema

[Krzysztof Kozlowski]

On 29/03/2021 21:46, Dmitry Osipenko wrote:
> Convert Tegra20 Memory Controller binding to schema.
> 
> Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>

Thanks for the patch! Please see a comment below.

> ---
>  .../memory-controllers/nvidia,tegra20-mc.txt  | 40 ----------
>  .../memory-controllers/nvidia,tegra20-mc.yaml | 78 +++++++++++++++++++
>  2 files changed, 78 insertions(+), 40 deletions(-)
>  delete mode 100644 Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-mc.txt
>  create mode 100644 Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-mc.yaml
> 
> diff --git a/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-mc.txt b/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-mc.txt
> deleted file mode 100644
> index 739b7c6f2e26..000000000000
> --- a/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-mc.txt
> +++ /dev/null
> @@ -1,40 +0,0 @@
> -NVIDIA Tegra20 MC(Memory Controller)
> -
> -Required properties:
> -- compatible : "nvidia,tegra20-mc-gart"
> -- reg : Should contain 2 register ranges: physical base address and length of
> -  the controller's registers and the GART aperture respectively.
> -- clocks: Must contain an entry for each entry in clock-names.
> -  See ../clocks/clock-bindings.txt for details.
> -- clock-names: Must include the following entries:
> -  - mc: the module's clock input
> -- interrupts : Should contain MC General interrupt.
> -- #reset-cells : Should be 1. This cell represents memory client module ID.
> -  The assignments may be found in header file <dt-bindings/memory/tegra20-mc.h>
> -  or in the TRM documentation.
> -- #iommu-cells: Should be 0. This cell represents the number of cells in an
> -  IOMMU specifier needed to encode an address. GART supports only a single
> -  address space that is shared by all devices, therefore no additional
> -  information needed for the address encoding.
> -- #interconnect-cells : Should be 1. This cell represents memory client.
> -  The assignments may be found in header file <dt-bindings/memory/tegra20-mc.h>.
> -
> -Example:
> -	mc: memory-controller@7000f000 {
> -		compatible = "nvidia,tegra20-mc-gart";
> -		reg = <0x7000f000 0x400		/* controller registers */
> -		       0x58000000 0x02000000>;	/* GART aperture */
> -		clocks = <&tegra_car TEGRA20_CLK_MC>;
> -		clock-names = "mc";
> -		interrupts = <GIC_SPI 77 0x04>;
> -		#reset-cells = <1>;
> -		#iommu-cells = <0>;
> -		#interconnect-cells = <1>;
> -	};
> -
> -	video-codec@6001a000 {
> -		compatible = "nvidia,tegra20-vde";
> -		...
> -		resets = <&mc TEGRA20_MC_RESET_VDE>;
> -		iommus = <&mc>;
> -	};
> diff --git a/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-mc.yaml b/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-mc.yaml
> new file mode 100644
> index 000000000000..c5731fa41e83
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra20-mc.yaml
> @@ -0,0 +1,78 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/memory-controllers/nvidia,tegra20-mc.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: NVIDIA Tegra20 SoC Memory Controller
> +
> +maintainers:
> +  - Dmitry Osipenko <digetx@xxxxxxxxx>
> +  - Jon Hunter <jonathanh@xxxxxxxxxx>
> +  - Thierry Reding <thierry.reding@xxxxxxxxx>
> +
> +description: |
> +  The Tegra20 Memory Controller merges request streams from various client
> +  interfaces into request stream(s) for the various memory target devices,
> +  and returns response data to the various clients. The Memory Controller
> +  has a configurable arbitration algorithm to allow the user to fine-tune
> +  performance among the various clients.
> +
> +  Tegra20 Memory Controller includes the GART (Graphics Address Relocation
> +  Table) which allows Memory Controller to provide a linear view of a
> +  fragmented memory pages.
> +
> +properties:
> +  compatible:
> +    const: nvidia,tegra20-mc-gart
> +
> +  reg:
> +    minItems: 1
> +    maxItems: 2

I think you always need two regs, don't you? If so, then better to use
"description" like in
Documentation/devicetree/bindings/example-schema.yaml to describe which
set is for which range/purpose.


Best regards,
Krzysztof