Re: [PATCH V7 1/1] drivers/gpio: Altera soft IP GPIO driver and devicetree binding

From: Tien Hock Loh
Date: Mon Apr 21 2014 - 02:59:38 EST


On Isn, 2014-04-07 at 12:11 -0500, Josh Cartwright wrote:
> On Mon, Apr 07, 2014 at 04:00:43PM +0800, Tien Hock Loh wrote:
> > On Wed, Mar 19, 2014 at 6:09 PM, Tien Hock Loh <thloh@xxxxxxxxxx> wrote:
> > > On Fri, Mar 7, 2014 at 11:14 PM, Josh Cartwright <joshc@xxxxxxxxxxxxxx> wrote:
> > >> On Mon, Mar 03, 2014 at 06:27:43PM +0800, thloh@xxxxxxxxxx wrote:
> > >>> From: Tien Hock Loh <thloh@xxxxxxxxxx>
> [..]
> > >>> + altera_gc->mapped_irq = irq_of_parse_and_map(node, 0);
> > >>>
> > >>
> > >> platform_get_irq(pdev, 0);
> > >>
> > > OK.
> > >
> >
> > platform_get_irq doesn't create the irq mapping which is needed by the
> > driver. Since this driver is targeted at using of, should I be using
> > irq_of_parse_and_map or should I still redo the codes with
> > platform_get_irq and irq_create_mapping? I think the latter would be
> > introducing code redundancy. Please advice.
>
> Yes, it is technically true that platform_get_irq() doesn't do the
> mapping directly, but that's because the mapping is setup earlier, when
> of_device_alloc() (drivers/of/platform.c) allocates resources for your
> platform device.
>
> Calling irq_of_parse_and_map() should be unnecessary.

I checked and tried running the without irq_create_mapping but it seems
the mapping is not done. What I've seen other GPIO driver is doing is to
create the mapping during the gpio_to_irq call. However Linus suggested
we are avoiding that route, thus the use of irq_of_parse_and_map.

Do you agree with my findings?

>


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