* Florian Fainelli <f.fainelli@xxxxxxxxx> [171129 18:17]: > On 11/29/2017 09:45 AM, Tony Lindgren wrote: > > * Florian Fainelli <f.fainelli@xxxxxxxxx> [171129 17:37]: > >> On 11/29/2017 09:01 AM, Tony Lindgren wrote: > >>> * Florian Fainelli <f.fainelli@xxxxxxxxx> [171102 23:18]: > >>>> It may happen that a device needs to force applying a state, e.g: > >>>> because it only defines one state of pin states (default) but loses > >>>> power/register contents when entering low power modes. Add a > >>>> pinctrl_dev::flags bitmask to help describe future quirks and define > >>>> PINCTRL_FLG_FORCE_STATE as such a settable flag. > >>> > >>> It makes sense to tag the existing state with the context loss > >>> information as otherwise we'll be duplicating the state in the > >>> pinctrl driver potentially for hundreds of pins. > >>> > >>> Maybe this patch description should clarify that it's the > >>> pinctrl device restoring the pin state, not the pinctrl > >>> consumer devices? > >>> > >>> So maybe just "a pinctrl device needs to force apply a state" > >>> instead of just device above? > >> > >> It's a bit more involved than that, the pinctrl consumer device might > >> want to restore a particular state by calling pinctrl_select_state(), > >> however, because of the (p->state == state)check, the pinctrl provider > >> driver has no chance of making that call do the actual HW programming. > > > > Hmm but isn't it the pinctrl provider device losing context here? > > It is the pinctrl provider indeed. > > > I think the restore of the pin state should somehow happen automatically > > by the pinctrl provider driver without a need for the pinctrl consumer > > drivers to do anything. > > Correct. OK thanks for confirming that. > > Or what's the use case for pinctrl consumer driver wanting to store > > a pin? > > I actually meant that a consumer driver could aalso call > pinctrl_select_state() in one of its resume callback for instance, but > if the pinctrl provider driver does nothing (or rather the core, on > behalf of the provider), this would be an issue. This was not super > clear, so I will stop using that example from now on :) OK yeah that's probably where the confusion comes from :) Tony -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
