On Fri, 23 Nov 2012 23:03:47 +0530, Viresh Kumar <viresh.ku...@linaro.org>
wrote:
> On 23 November 2012 15:11, Grant Likely <grant.lik...@secretlab.ca> wrote:
> > On Fri, 23 Nov 2012 00:26:20 +0530, Viresh Kumar <viresh.ku...@linaro.org>
> > wrote:
>
> >> + - irq-trigger : IRQ trigger to use for the
> >> interrupt to the host
> >> + - irq-invert-polarity : bool, IRQ line is connected with
> >> reversed polarity
> >
> > This looks odd. Normally the interrupt polarity should be encoded in the irq
> > specifier flags field.
>
> Hi Grant and Lee Jones,
>
> This looks odd because stmpe is odd, i am taking the discussion held
> with Lee jones to this thread.
>
> So, how interrupt stuff works currently in DT..
> We have a interrupt controller IC:
>
> ic: interrupt-controller@40008000 {
> compatible = "foo";
> interrupt-controller;
> #interrupt-cells = <2>;
> ...
> };
>
> And we have a user of this IC:
>
> foo-peripheral@40048000 {
> compatible = "foo-peripheral";
> interrupt-parent = <&ic>;
> interrupts = <39 4>;
> };
>
> Here first field of "interrupts" gives interrupt line number and the second
> one
> gives polarity, interrupt type etc..
>
> All is good till now. Now, every interrupt controller supports the first
> field, but the second one depends on its capabilities. An interrupt controller
> might not have registers to configure interrupt polarity, type, etc of
> the interrupt
> it will service and so the second field wouldn't be available for them.
>
> For now just think stmpe is not a MFD and not a interrupt controller
> either. It is
> just a simple device, dev-foo.
>
> It will declare values of its interrupts field based on the type of
> interrupt controller
> that will service its interrupt and that can be anything like VIC/GIC/GPIO
> controller.
Ah, so it is configuring the way the device emits interrupts; not how
the interrupt controller processes them. Fair enough.
It would actually be good to ask the interrupt controller driver what
kind of interrupt signal it expects for a given interrupt line. That
should also solve the problem and I think it would be more useful to
other devices. Can you investigate whether or not
irqd_get_trigger_type() returns the information you need?
g.
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