Re: [PATCH v3 7/9] dt-bindings: mtd: Split ECC engine with rawnand controller

[Miquel Raynal <miquel.raynal@bootlin.com>]

Hi Krzysztof,

krzysztof.kozlowski@linaro.org wrote on Thu, 8 Dec 2022 11:27:27 +0100:

> 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.

Thanks for the details. Any chances this can eventually be fixed at
dt-schema level?

Thanks,
Miquèl