On 09/13/18 08:59, Thierry Reding wrote: > Hi everyone, > > I've been trying to implement a feature on recent Tegra chips that's > called "wake events". These wake events are implemented as part of the > power management controller (PMC) and they control which events can be > used to wake the system from suspend. Events include things like an > alarm interrupt from an RTC, or the GPIO interrupt hooked up to a > power button for example. > > We already have a driver for a couple of other things that the PMC does, > so I thought it'd be natural to implement this functionality as an IRQ > chip in the PMC driver. The way that this would work is that for all the > devices that are wakeup sources, we'd end up specifying the PMC as the > interrupt parent and the PMC would then itself have the main GIC as its > parent. That way, the hierarchical IRQ domain infrastructure would take > care of pretty much everything. > > Unfortunately I've run into some issues here. One problem that I'm > facing is that PMC could have more than one parent. For example, the RTC > alarm interrupt goes straight to the GIC, but the power button GPIO goes > through the GPIO controller first and then to the GIC. This doesn't seem > to be something that's currently possible. > > The way I imagine this to work from a DT perspective is as follows: There is an interrupts-extended property which as a first cell takes a phandle to the parent interrupt controller, e.g: interrupts-extended = <&gic 73 GIPC_SPI IRQ_TYPE_LEVEL_HIGH>, <&pmc 10>; (provided that I understood your problem and example correctly). We have a similar use case on our STB chips where we have "main" interrupts wired to the ARM GIC and wake-up interrupts wired to a specific wake-up interrupt controller in an always-on domain. The two controllers have a different #interrupt-cells specifier. The interrupt infrastructure in Linux already knows how to deal with that and whether you use of_get_irq() or platform_get_irq() you should obtain the correct virtual interrupt numbers that you expected, parented to the appropriate interrupt controller. Hope this helps. -- Florian
