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SubjectRe: [PATCH v8 1/3] dt-bindings: mmc: mtk-sd: extend interrupts and pinctrls properties
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Il 22/03/22 02:35, Axe Yang ha scritto:
> On Mon, 2022-03-21 at 18:29 -0500, Rob Herring wrote:
>> On Mon, Mar 21, 2022 at 07:51:32PM +0800, Axe Yang wrote:
>>> Extend interrupts and pinctrls for SDIO wakeup interrupt feature.
>>> This feature allow SDIO devices alarm asynchronous interrupt to
>>> host
>>> even when host stop providing clock to SDIO card. An extra wakeup
>>> interrupt and pinctrl states for SDIO DAT1 pin state switching are
>>> required in this scenario.
>>>
>>> Signed-off-by: Axe Yang <axe.yang@mediatek.com>
>>> ---
>>> .../devicetree/bindings/mmc/mtk-sd.yaml | 23
>>> ++++++++++++++++++-
>>> 1 file changed, 22 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/Documentation/devicetree/bindings/mmc/mtk-sd.yaml
>>> b/Documentation/devicetree/bindings/mmc/mtk-sd.yaml
>>> index 297ada03e3de..f57774535a1d 100644
>>> --- a/Documentation/devicetree/bindings/mmc/mtk-sd.yaml
>>> +++ b/Documentation/devicetree/bindings/mmc/mtk-sd.yaml
>>> @@ -69,12 +69,23 @@ properties:
>>> - const: ahb_cg
>>>
>>> interrupts:
>>> - maxItems: 1
>>> + description:
>>> + Should at least contain MSDC GIC interrupt. To support SDIO
>>> in-band wakeup, an extended
>>> + interrupt is required and be configured as wakeup source
>>> irq.
>>> + minItems: 1
>>> + maxItems: 2
>>>
>>> pinctrl-names:
>>> + description:
>>> + Should at least contain default and state_uhs. To support
>>> SDIO in-band wakeup, dat1 pin
>>> + will be switched between GPIO mode and SDIO DAT1 mode,
>>> state_eint and state_dat1 are
>>> + mandatory in this scenarios.
>>> + minItems: 2
>>> items:
>>> - const: default
>>> - const: state_uhs
>>> + - const: state_eint
>>> + - const: state_dat1
>>>
>>> pinctrl-0:
>>> description:
>>> @@ -86,6 +97,16 @@ properties:
>>> should contain uhs mode pin ctrl.
>>> maxItems: 1
>>>
>>> + pinctrl-2:
>>> + description:
>>> + should switch dat1 pin to GPIO mode.
>>> + maxItems: 1
>>> +
>>> + pinctrl-3:
>>> + description:
>>> + should switch SDIO dat1 pin from GPIO mode back to SDIO
>>> mode.
>>
>> How is this different than pinctrl-0?
>
> pinctrl-0 contains default settings for all IO pins(CLK/CMD/DAT).
> pinctrl-1 contains settings for all IO pins(CLK/CMD/DAT) in UHS mode.
> pinctrl-3 is lightweight pinctrl-1, only keep SDIO DAT1 pin function
> switch part.
>

Is there any particular reason why we cannot simply select pinctrl-1 again
instead of pinctrl-3, apart from the virtually not existent overhead of
one more mmio write?

> ...
>
> Regards,
> Axe
>

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