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Message-ID: <f3e3a3d0-6d21-c782-38a2-c8b2c36242c3@linaro.org>
Date:   Thu, 8 Dec 2022 11:27:27 +0100
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Subject: Re: [PATCH v3 7/9] dt-bindings: mtd: Split ECC engine with rawnand
 controller
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To:     Miquel Raynal <miquel.raynal@bootlin.com>
Cc:     Xiangsheng Hou <xiangsheng.hou@mediatek.com>,
        Richard Weinberger <richard@nod.at>,
        Vignesh Raghavendra <vigneshr@ti.com>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Mark Brown <broonie@kernel.org>,
        Chuanhong Guo <gch981213@gmail.com>,
        linux-mtd@lists.infradead.org, devicetree@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-spi@vger.kernel.org, benliang.zhao@mediatek.com,
        bin.zhang@mediatek.com
References: <20221208062955.2546-1-xiangsheng.hou@mediatek.com>
 <20221208062955.2546-8-xiangsheng.hou@mediatek.com>
 <fe70d964-229a-8bda-a414-e009dd955e5e@linaro.org>
 <20221208110035.5649a051@xps-13>
From:   Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
In-Reply-To: <20221208110035.5649a051@xps-13>
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On 08/12/2022 11:00, Miquel Raynal wrote:
> Hi Krzysztof,
> 
> krzysztof.kozlowski@linaro.org wrote on Thu, 8 Dec 2022 10:44:17 +0100:
> 
>> On 08/12/2022 07:29, Xiangsheng Hou wrote:
>>> Split MediaTek ECC engine with rawnand controller and convert to
>>> YAML schema.
>>>
>>> Signed-off-by: Xiangsheng Hou <xiangsheng.hou@mediatek.com>
>>> ---
>>>  .../bindings/mtd/mediatek,mtk-nfc.yaml        | 154 +++++++++++++++
>>>  .../mtd/mediatek,nand-ecc-engine.yaml         |  62 ++++++
>>>  .../devicetree/bindings/mtd/mtk-nand.txt      | 176 ------------------
>>>  3 files changed, 216 insertions(+), 176 deletions(-)
>>>  create mode 100644 Documentation/devicetree/bindings/mtd/mediatek,mtk-nfc.yaml
>>>  create mode 100644 Documentation/devicetree/bindings/mtd/mediatek,nand-ecc-engine.yaml
>>>  delete mode 100644 Documentation/devicetree/bindings/mtd/mtk-nand.txt
>>>
>>> diff --git a/Documentation/devicetree/bindings/mtd/mediatek,mtk-nfc.yaml b/Documentation/devicetree/bindings/mtd/mediatek,mtk-nfc.yaml
>>> new file mode 100644
>>> index 000000000000..eb1a44c7ae4e
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/mtd/mediatek,mtk-nfc.yaml
>>> @@ -0,0 +1,154 @@
>>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>>> +%YAML 1.2
>>> +---
>>> +$id: http://devicetree.org/schemas/mtd/mediatek,mtk-nfc.yaml#
>>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>>> +
>>> +title: MediaTek(MTK) SoCs raw NAND FLASH controller (NFC)
>>> +
>>> +maintainers:
>>> +  - Xiangsheng Hou <xiangsheng.hou@mediatek.com>
>>> +
>>> +properties:
>>> +  compatible:
>>> +    enum:
>>> +      - mediatek,mt2701-nfc
>>> +      - mediatek,mt2712-nfc
>>> +      - mediatek,mt7622-nfc
>>> +
>>> +  reg:
>>> +    items:
>>> +      - description: Base physical address and size of NFI.
>>> +
>>> +  interrupts:
>>> +    items:
>>> +      - description: NFI interrupt
>>> +
>>> +  clocks:
>>> +    items:
>>> +      - description: clock used for the controller
>>> +      - description: clock used for the pad
>>> +
>>> +  clock-names:
>>> +    items:
>>> +      - const: nfi_clk
>>> +      - const: pad_clk
>>> +
>>> +  ecc-engine:
>>> +    description: device-tree node of the required ECC engine.
>>> +    $ref: /schemas/types.yaml#/definitions/phandle
>>> +
>>> +patternProperties:
>>> +  "^nand@[a-f0-9]$":
>>> +    type: object  
>>
>> This should be instead:
>>     $ref: nand-chip.yaml#
>>     unevaluatedProperties: false
>>
>> and then properties below (due to current dtschema limitations) should
>> list properties from nand-controller.yaml:
>>
>>       nand-on-flash-bbt: true
>>
>> Optionally, we could create additional schema - nand-controller-chip,
>> which would be referenced directly by nand-controller and itself would
>> ref nand-chip.
> 
> Isn't this enough? (in linux-next)
> https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git/tree/Documentation/devicetree/bindings/mtd/nand-controller.yaml?h=mtd/next#n54

No, I tested it and it does not work as intended. In this particular
case. I think this is a limitation of dtschema, because binding itself
looks fine. The problem is that you have:
1. mtk-nfc having nand@ children. mtk-nfc references nand-controller
which brings these children.
2. However nand-controller while bringing these children does two things:
a. ref: nand-chip
b. add more propeties

3. The mtk-nfc must further extend the nand@ child.
4. If you add "unevaluatedProperties: false" you notice warnings of
unevaluated propertie from nand-controller children.

Best regards,
Krzysztof