On Thu, Mar 23, 2023 at 11:00:32AM -0700, Doug Anderson wrote: > Hi, > > On Thu, Mar 23, 2023 at 10:45 AM Charles Keepax > <ckeepax@xxxxxxxxxxxxxxxxxxxxx> wrote: > > > > I think really the best place to look at this would be at the > > regulator level. It is fine if mfd_add_devices passes, the problem > > really is that the regulator core doesn't realise the regulator is > > going to be arriving, and thus returns a dummy regulator, rather > > than returning EPROBE_DEFER. If it did the MFD driver would probe > > defer at the point of requesting the regulator, which would all > > make sense. > > I think something like your suggestion could be made to work for the > "microphone" supply in the arizona MFD, but not for the others looked > at here. > > The problem is that if the MFD driver gets -EPROBE_DEFER then it will > go through its error handling path and call mfd_remove_devices(). > That'll remove the sub-device providing the regulator. If you try > again, you'll just do the same. :-) > > Specifically in wm8994 after we've populated the regulator sub-devices > then we turn them on and start talking to the device. > > I think the two options I have could both work for wm8994's case: > either add some type of "my children have done probing" to MFD and > move the turning on of regulators / talking to devices there, or add > another stub-device and add it there. ;-) Is this true if we keep the regulator as sync though? Yes it will remove the children but when it re-adds them the reason that the regulator probe deferred in the first place will hopefully be removed. So it will now fully probe in path. Thanks, Charles
