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SubjectRe: [PATCH v4 1/3] dt-bindings: mmc: add cap-sdio-async-irq flag
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On Mon, 2022-02-14 at 16:23 +0100, Ulf Hansson wrote:
> On Wed, 19 Jan 2022 at 11:32, Axe Yang <axe.yang@mediatek.com> wrote:
> >
> > Asynchronous interrupt is a mechanism that allow SDIO devices alarm
> > interrupt when host stop providing clock to card. Add a DT flag to
> > enable this feature if it is supported by SDIO card.
> >
> > Signed-off-by: Axe Yang <axe.yang@mediatek.com>
> > ---
> > Documentation/devicetree/bindings/mmc/mmc-controller.yaml | 5
> > +++++
> > 1 file changed, 5 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/mmc/mmc-
> > controller.yaml b/Documentation/devicetree/bindings/mmc/mmc-
> > controller.yaml
> > index 513f3c8758aa..16fb06f88471 100644
> > --- a/Documentation/devicetree/bindings/mmc/mmc-controller.yaml
> > +++ b/Documentation/devicetree/bindings/mmc/mmc-controller.yaml
> > @@ -165,6 +165,11 @@ properties:
> > description:
> > eMMC hardware reset is supported
> >
> > + cap-sdio-async-irq:
> > + $ref: /schemas/types.yaml#/definitions/flag
> > + description:
> > + SDIO async interrupt is supported.
>
> We already have a DT property for this, I believe.
>
> "wakeup-source" is probably what you want, but we have additional
> properties that are related to this too. See more below.
>
> > +
> > cap-sdio-irq:
> > $ref: /schemas/types.yaml#/definitions/flag
> > description:
>
> The above, "cap-sdio-irq", informs whether the SDIO IRQs can be
> supported at all, by the host controller.
>
> The property "keep-power-in-suspend" informs whether we can preserve
> the power to the card during a suspend/resume cycle. This should be
> needed in your case too, I think.
>
> In other words, you may need to combine "cap-sdio-irq",
> "wakeup-source" and "keep-power-in-suspend" to describe your HW.
>
> However, what perhaps is missing, is a common MMC/SDIO binding that
> let us describe an optional irq-line, which sometimes is being used
> for the wakeup irq. In the sdhci-omap case, we look for an irq
> mapping
> towards "wakeup" if specified in the "interrupt-names" property.
>
> In some case, when the SDIO card supports an out-of-band IRQ line,
> the
> similar should be specified in the child-node corresponding to the
> SDIO card.
>
>

Yes, the intention of the patchset is to wakeup SDIO host in
runtime/system suspend state within SDIO DAT1(in-band wakeup).

I will implement it with "wakeup-source", thanks for your review.

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