On 01/05/2020 08:00:11-0500, Rob Herring wrote: > > I don't think this is true because in the case of a discrete RTC, its > > interrupt pin can be connected directly to a PMIC to power up a board > > instead of being connected to the SoC. In that case we don't have an > > interrupt property but the RTC is still a wakeup source. This is the > > usual use case for wakeup-source in the RTC subsystem. Else, if there is > > an interrupt, then we assume the RTC is a wakeup source and there is no > > need to have the wakeup-source property. > > Yes, that would be an example of "unless the wakeup mechanism is > somehow not an interrupt". I guess I should add not an interrupt from > the perspective of the OS. > > So if the wakeup is self contained within the PMIC, why do we need a > DT property? The capability is always there and enabling/disabling > wakeup from it is userspace policy. > Yes, for this particular case, I'm not sure wakeup-source is actually necessary. If the interrupt line is used to wakeup the SoC, then the presence of the interrupts property is enough to enable wakeup. -- Alexandre Belloni, Bootlin Embedded Linux and Kernel engineering https://bootlin.com
