On Tue, Feb 10, 2015 at 03:52:01PM +0000, Boris Brezillon wrote: > Hi Mark, > > On Tue, 10 Feb 2015 15:36:28 +0000 > Mark Rutland <mark.rutland@xxxxxxx> wrote: > > > Hi Boris, > > > > On Thu, Jan 29, 2015 at 10:33:38AM +0000, Boris Brezillon wrote: > > > Add documentation for the virtual irq demuxer. > > > > > > Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxxxxxxx> > > > Acked-by: Nicolas Ferre <nicolas.ferre@xxxxxxxxx> > > > --- > > > .../bindings/interrupt-controller/dumb-demux.txt | 41 ++++++++++++++++++++++ > > > 1 file changed, 41 insertions(+) > > > create mode 100644 Documentation/devicetree/bindings/interrupt-controller/dumb-demux.txt > > > > > > diff --git a/Documentation/devicetree/bindings/interrupt-controller/dumb-demux.txt b/Documentation/devicetree/bindings/interrupt-controller/dumb-demux.txt > > > new file mode 100644 > > > index 0000000..b9a7830 > > > --- /dev/null > > > +++ b/Documentation/devicetree/bindings/interrupt-controller/dumb-demux.txt > > > @@ -0,0 +1,41 @@ > > > +* Virtual Interrupt Demultiplexer > > > + > > > +This virtual demultiplexer simply forward all incoming interrupts to its > > > +enabled/unmasked children. > > > +It is only intended to be used by hardware that do not provide a proper way > > > +to demultiplex a source interrupt, and thus have to wake all their children > > > +up so that they can possibly handle the interrupt (if needed). > > > +This can be seen as an alternative to shared interrupts when at least one > > > +of the interrupt children is a timer (and require the irq to stay enabled > > > +on suspend) while others are not. This will prevent calling irq handlers of > > > +non timer devices while they are suspended. > > > > This sounds like a DT-workaround for a Linux implementation problem, and > > I don't think this the right way to solve your problem. > > I understand your concern, but why are you answering while I asked for > DT maintainers reviews for several days (if not several weeks). I am sorry that I did not spot those, and I am very sorry that this means I am only now able to air my concerns. > > Why does this have to be in DT at all? Why can we not fix the core to > > handle these details? > > We already discussed that with Rob and Thomas, and hiding such a > demuxer chip is not an easy task. > I'm open to any suggestion to do that, though I'd like you (I mean DT > guys) to provide a working implementation (or at least a viable concept) > that would silently demultiplex an irq. Is it truly necessary to drop a emux in the middle? As far as I can see, all that we're attempting to do here is hide the IRQF_NO_SUSPEND mismatch from the core IRQ code, though I've only just started digging and haven't yet figured out where/why the core code cares. Any hints? > > I am very much not keen on this binding. > > Yes, but do you have anything else to propose. > We're experiencing this warning for 2 releases now, and this is time to > find a solution (even if it's not a perfect one). I appreciate this, and I am really sorry that I have come to this so late. > > > +Required properties: > > > +- compatible: Should be "virtual,irq-demux". > > > +- interrupt-controller: Identifies the node as an interrupt controller. > > > +- interrupts-extended or interrupt-parent and interrupts: Reference the source > > > + interrupt connected to this dumb demuxer. > > > +- #interrupt-cells: The number of cells to define the interrupts (should be 1). > > > + The only cell is the IRQ number. > > > +- irqs: u32 bitfield specifying the interrupts provided by the demuxer. > > > > Arbitrary limitation? > > I first proposed to make this field unlimited, but Thomas suggested to > keep it limited to 32 bits (and I didn't complain since my HW needs > far less than 32 interrupts). Ok. Thanks, Mark. -- 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
