Re: [PATCH] RFC: interrupt consistency check for OF GPIO IRQs

[Alexander Holler]

Am 12.09.2013 12:28, schrieb Alexander Holler:
> Am 12.09.2013 12:11, schrieb Javier Martinez Canillas:
> > On 09/12/2013 10:55 AM, Alexander Holler wrote:
>
> ...
> > > By the way, how do you define two GPIOs/IRQs from different
> > > gpio-banks/irq-controllers wuth that scheme?
> >
> > That is indeed a very good question and I don't have a definite answer.
> >
> > > Would that be like below?
> > >
> > >   ethernet@5,0 {
> > >            compatible = "smsc,lan9221", "smsc,lan9115";
> > >            interrupt-parent = <&gpio6>;
> > >            interrupts = <16 8>;
> > >            interrupt-parent = <&gpio7>;
> > >            interrupts = <1 IRQF_TRIGGER_FALLING>; /* GPIO7_1 */
> > >   };
>
> ...
>
> > So, if I understood the code correctly the DT IRQ core doesn't expect
> > a device
> > node to have more than one "interrupt-parent" property.
> >
> > It *should* work though if you have multiple "interrupts" properties
> > defined and
> > all of them have the same "interrupt-parent":
> >
> >         interrupt-parent = <&gpio6>;
> >         interrupts = <1 IRQF_TRIGGER_HIGH>; /* GPIO6_1 */
> >         interrupts = <2 IRQF_TRIGGER_LOW>; /* GPIO6_2 */
> >
> > since of_irq_map_one() will be called for each "interrupts" and the
> > correct
> > "interrupt-parent" will get obtained by of_irq_find_parent().
>
> I assumed that answer. So to make such a scenario possible, something
> like this might be neccessary:
>
>           interrupts = <&gpio6 1 IRQF_TRIGGER_HIGH>; /* GPIO6_1 */
>           interrupts = <&gpio7 2 IRQF_TRIGGER_LOW>; /* GPIO7_2 */
>
> or, to be compatible
>
>           interrupts = <1 IRQF_TRIGGER_HIGH &gpio6>; /* GPIO6_1 */
>           interrupts = <1 IRQF_TRIGGER_LOW &gpio7>; /* GPIO7_1 */
>
> Another problem is the naming. In all the above cases, the driver would
> not know which IRQ he should use for what. Maybe the order defines it,
> but that wouldn't be very verbose. And I think just changing the name
> would make travelling the tree impossible, as only the driver itself
> would know the name and it's meaning.

On a second look, travelling the tree is still possible if the solution 
would be like above (without that interrupt-parent). So if a driver 
requires two interrupts he could use

      interrupt-foo = <1 IRQF_TRIGGER_HIGH &gpio6>; /* GPIO6_1 */
      interrupt-bar = <1 IRQF_TRIGGER_LOW &gpio7>; /* GPIO7_1 */

And travelling the tree will still be possible because walking from the 
interrupt-controllers (those gpio) downwards would end up at the 
interrupt definitions, so the name of them isn't needed to find them in 
the tree.

Regards,

Alexander Holler

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/