Re: DT property keep-power-in-suspend and how WiFi drivers use it

[...]

> >>>
> >>> The corresponding SDIO func-driver may call
> >>> sdio_set_host_pm_flags(func, MMC_PM_KEEP_POWER). In this way, the mmc
> >>> core will leave the SDIO card powered-on during system suspend.
> >>> Although, unless it's really necessary, it's ofcourse a bad idea as it
> >>> would mean wasting energy when the system is suspended.
> >>
> >> Just to get my understanding right: The brcm_fmac driver would be the
> >> SDIO func-driver in my case, right?
> >
> > Correct. The one that is registered with sdio_register_driver().
>
> I guess I would just write a patch for the corresponding SDIO
> func-driver, adding a DeviceTree property directly in that SDIO
> func-driver (not the mmc host driver) so this can be enabled just for
> these specific boards, or would you suggest a different solution?

Right, a DT property indicating that we can't power-cycle the SDIO
card is probably the correct way.

We have a bunch of properties already in the host's node related to
this, so adding another one there should be fine too, I think.
Otherwise, an SDIO func device may be described in a child-node of the
mmc host's node (see
Documentation/devicetree/bindings/mmc/mmc-controller-common.yaml).

Kind regards
Uffe