Re: [PATCH v10 1/6] dt-bindings: mmc: Extend keep-power-in-suspend beyond SDIO

[Kamal Dasu]

On Tue, Oct 27, 2026 at 3:48 PM Ulf Hansson
<ulf.hansson@xxxxxxxxxxxxxxxx> wrote:
>
> On Tue, Oct 27, 2026 at 4:33 PM Krzysztof Kozlowski <krzk@xxxxxxxxxx> wrote:
> >
> > On 27/10/2026 15:40, Ulf Hansson wrote:
> > > From: Kamal Dasu <kamal.dasu@xxxxxxxxxxxx>
> > >
> > > keep-power-in-suspend is currently documented as SDIO-only, but the
> > > requirement it describes -- preserving card power across a
> > > suspend/resume cycle -- applies just as well to any card type. Drop
> > > the SDIO-only restriction so eMMC and SD platforms can use it too.
> > >
> > > Signed-off-by: Kamal Dasu <kamal.dasu@xxxxxxxxxxxx>
> > > Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxxxxxxxx>
> >
> > Incomplete DCO.
>
> Sorry, I should have explicitly stated that I will leave that to Kamal
> to contribute on top.
>
> Kind regards
> Uffe

Hi Uffe,

No problem. I'll resend the two dt-bindings patches myself with the DCO
fixed and the DT list on Cc. Do you want them as a separate two-patch
series on top of your patches 3-6, or should I post the whole series
as v11?

On the SD wording, since you plan to add SD support too, I'll keep the
description as it is, unless Shawn or Krzysztof object.

> That said, I was also thinking that maybe it would make sense to add a
> sysfs node to allow the behavior to be controlled by userspace.
> Thoughts?

For this board the requirement is fixed hardware behaviour. Firmware
reads the card at every S3 resume, so the card has to stay powered and
be reset each time. Without both DT properties the board enters suspend
and then resets at resume, so I think the DT properties are the right
way to describe it.

A sysfs knob could make sense where it is a policy choice, for example
on SD. If it is added, I think it should not be possible to turn it off
when reset-card-at-resume is set in DT, since that would bring the
board back to the failing case. I would prefer to keep it out of this
series and add it separately when SD support is added.

Kamal

Attachment: smime.p7s
Description: S/MIME Cryptographic Signature