Hello,
I have a question regarding the usage of the Device Tree property
`keep-power-suspend`.
In the Device Tree documentation it reads:
"SDIO only. Preserves card power during a suspend/resume cycle."
Does that mean that the SDIO Host Controller will remain powered or
should this equally apply to anything that is connected to this SDIO
Host Controller?
To give a bit more background:
I have an embedded board with a brcm_fmac WiFi module. It seems that due
to a hardware limitation we are not permitted to switch the module off.
It simply cannot be re-probed afterwards.
The property `keep-power-in-suspend` was used and that used to work fine
until 92caded ("brcmfmac: Avoid keeping power to SDIO card
unless WOWL is used"), which made the wifi adapter by default turn off
on suspend to be re-probed on resume. Not working on our board...
I have also looked at other WiFi drivers with an SDIO interface and it
seems that none of them are really honoring the `keep-power-in-suspend`
flag. Is this flag for the SDIO Host Controller only?
What would be proper way to implement it so that the brcm_fmac return to
its old behaviour if necessary?
Add a Device Tree property directly for the brcm_fmac driver..?
I would like to write a patch, but I would like to know in which
direction to go.
Thank you for any feedback
Matthias
