Re: [PATCH] dt-bindings: dma: Convert mtk-uart-apdma to DT schema

[AngeloGioacchino Del Regno]

Il 16/02/22 14:26, Krzysztof Kozlowski ha scritto:
> On 16/02/2022 12:40, AngeloGioacchino Del Regno wrote:
> > Convert the MediaTek UART APDMA Controller binding to DT schema.
> >
> > Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>
> > ---
> >   .../bindings/dma/mediatek,uart-dma.yaml       | 112 ++++++++++++++++++
> >   .../bindings/dma/mtk-uart-apdma.txt           |  56 ---------
> >   2 files changed, 112 insertions(+), 56 deletions(-)
> >   create mode 100644 Documentation/devicetree/bindings/dma/mediatek,uart-dma.yaml
> >   delete mode 100644 Documentation/devicetree/bindings/dma/mtk-uart-apdma.txt
> >
> > diff --git a/Documentation/devicetree/bindings/dma/mediatek,uart-dma.yaml b/Documentation/devicetree/bindings/dma/mediatek,uart-dma.yaml
> > new file mode 100644
> > index 000000000000..4583c8f535b2
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/dma/mediatek,uart-dma.yaml
> > @@ -0,0 +1,112 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/dma/mediatek,uart-dma.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: MediaTek UART APDMA controller
> > +
> > +maintainers:
> > +  - Long Cheng <long.cheng@xxxxxxxxxxxx>
> > +
> > +description: |
> > +  The MediaTek UART APDMA controller provides DMA capabilities
> > +  for the UART peripheral bus.
> > +
> > +allOf:
> > +  - $ref: "dma-controller.yaml#"
> > +
> > +properties:
> > +  compatible:
> > +    oneOf:
> > +      - items:
> > +          - enum:
> > +              - mediatek,mt2712-uart-dma
> > +              - mediatek,mt8516-uart-dma
> > +          - const: mediatek,mt6577-uart-dma
> > +      - enum:
> > +          - mediatek,mt6577-uart-dma
> > +
> > +  reg:
> > +    minItems: 1
> > +    maxItems: 16
> > +
> > +  interrupts:
> > +    description: |
> > +      TX, RX interrupt lines for each UART APDMA channel
> > +    minItems: 1
>
> It would be useful to have an "if:" block constraining the interrupts
> (and reg array?), if the dma-requests is missing. If you need an
> example, see length of "max8997,pmic-buck1-dvs-voltage" array in
> relation to presence of max8997,pmic-buck1-uses-gpio-dvs.
> https://elixir.bootlin.com/linux/v5.17-rc2/source/Documentation/devicetree/bindings/regulator/maxim,max8997.yaml#L259
>
> The best would be to restrict number of interrupts to number of
> requests, but I think dtschema cannot express this.

Thank you for the very much appreciated example!

I don't think that dtschema can express that without an if block... so, I'll
use that.

> > +    maxItems: 32
> > +
> > +  clocks:
> > +    description: Must contain one entry for the APDMA main clock
> > +    maxItems: 1
> > +
> > +  clock-names:
> > +    const: apdma
> > +
> > +  "#dma-cells":
> > +    const: 1
> > +    description: |
> > +      The first cell specifies the UART APDMA channel number
> > +
> > +  dma-requests:
> > +    description: |
> > +      Number of virtual channels of the UART APDMA controller
> > +    maximum: 16
> > +
> > +  mediatek,dma-33bits:
> > +    type: boolean
> > +    description: Enable 33-bits UART APDMA support
> > +
> > +required:
> > +  - compatible
> > +  - reg
> > +  - interrupts
> > +  - "#dma-cells"
>
> No need for requiring dma-cells. It is coming from dma-common.yaml.

Right. Forgot about that, will fix!

> > +
>
> Best regards,
> Krzysztof