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Date: Mon, 6 May 2024 09:14:44 +0200
From: Miquel Raynal <miquel.raynal@bootlin.com>
To: Keguang Zhang via B4 Relay <devnull+keguang.zhang.gmail.com@kernel.org>
Cc: keguang.zhang@gmail.com, Richard Weinberger <richard@nod.at>, Vignesh
 Raghavendra <vigneshr@ti.com>, Rob Herring <robh@kernel.org>, Krzysztof
 Kozlowski <krzysztof.kozlowski+dt@linaro.org>, Conor Dooley
 <conor+dt@kernel.org>, linux-mtd@lists.infradead.org,
 linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org,
 devicetree@vger.kernel.org
Subject: Re: [PATCH v7 1/3] dt-bindings: mtd: Add Loongson-1 NAND Controller
Message-ID: <20240506091444.59228fa9@xps-13>
In-Reply-To: <20240430-loongson1-nand-v7-1-60787c314fa4@gmail.com>
References: <20240430-loongson1-nand-v7-0-60787c314fa4@gmail.com>
	<20240430-loongson1-nand-v7-1-60787c314fa4@gmail.com>
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Hello,

devnull+keguang.zhang.gmail.com@kernel.org wrote on Tue, 30 Apr 2024
19:11:10 +0800:

> From: Keguang Zhang <keguang.zhang@gmail.com>
>=20
> Add devicetree binding document for Loongson-1 NAND Controller.
>=20
> Signed-off-by: Keguang Zhang <keguang.zhang@gmail.com>
> ---
> Changes in v7:
> - rename the file to loongson,ls1b-nfc.yaml
>=20
> Changes in v6:
> - A newly added patch
> ---
>  .../devicetree/bindings/mtd/loongson,ls1b-nfc.yaml | 66 ++++++++++++++++=
++++++
>  1 file changed, 66 insertions(+)
>=20
> diff --git a/Documentation/devicetree/bindings/mtd/loongson,ls1b-nfc.yaml=
 b/Documentation/devicetree/bindings/mtd/loongson,ls1b-nfc.yaml
> new file mode 100644
> index 000000000000..a69f22b9fd9e
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mtd/loongson,ls1b-nfc.yaml
> @@ -0,0 +1,66 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/mtd/loongson,ls1b-nfc.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Loongson-1 NAND Controller
> +
> +maintainers:
> +  - Keguang Zhang <keguang.zhang@gmail.com>
> +
> +allOf:
> +  - $ref: nand-controller.yaml
> +
> +properties:
> +  compatible:
> +    oneOf:
> +      - const: loongson,ls1b-nfc

What is the rationale behind this choice? Seems like the b variant has
two possible implementations and should always be preceded by a more
specific compatible.

As there is currently no description of this controller upstream, I
would not care too much about any out-of-tree description and directly
go for a clean description.

> +      - items:
> +          - enum:
> +              - loongson,ls1a-nfc
> +              - loongson,ls1c-nfc
> +          - const: loongson,ls1b-nfc
> +
> +  reg:
> +    maxItems: 1
> +
> +  dmas:
> +    maxItems: 1
> +
> +  dma-names:
> +    const: rxtx
> +
> +patternProperties:
> +  "^nand@[0-3]$":
> +    type: object
> +    $ref: raw-nand-chip.yaml
> +
> +    unevaluatedProperties: false
> +
> +required:
> +  - compatible
> +  - reg
> +  - dmas
> +  - dma-names

Should DMA props be required?

> +
> +unevaluatedProperties: false
> +
> +examples:
> +  - |
> +    nand-controller@1fe78000 {
> +        compatible =3D "loongson,ls1b-nfc";
> +        reg =3D <0x1fe78000 0x40>;
> +
> +        #address-cells =3D <1>;
> +        #size-cells =3D <0>;
> +
> +        dmas =3D <&dma 0>;
> +        dma-names =3D "rxtx";

There is a preferred spacing for DT nodes, see:
https://docs.kernel.org/devicetree/bindings/dts-coding-style.html

> +
> +        nand@0 {
> +            reg =3D <0>;
> +            nand-use-soft-ecc-engine;
> +            nand-ecc-algo =3D "hamming";

These two properties are not needed. Unless there is no hardware ECC
capability on this controller and in this case you need to ensure the
properties are present in the schema.

> +        };
> +    };
>=20


Thanks,
Miqu=C3=A8l