linux-kernel - Re: [PATCH] mfd: arizona: convert to regmap_add_irq

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Message-ID: <20120730180352.GR4468@opensource.wolfsonmicro.com>
Date:	Mon, 30 Jul 2012 19:03:52 +0100
From:	Mark Brown <broonie@...nsource.wolfsonmicro.com>
To:	Stephen Warren <swarren@...dotorg.org>
Cc:	Samuel Ortiz <sameo@...ux.intel.com>, linux-kernel@...r.kernel.org,
	Stephen Warren <swarren@...dia.com>
Subject: Re: [PATCH] mfd: arizona: convert to regmap_add_irq_chips

On Mon, Jul 30, 2012 at 11:05:08AM -0600, Stephen Warren wrote:
> On 07/29/2012 02:38 PM, Mark Brown wrote:
> > On Fri, Jul 27, 2012 at 01:02:56PM -0600, Stephen Warren wrote:

> >> 1) regmap_add_irq_chips() calls regmap_add_irq_chip() with irq==0 rather
> >>    than -1, so in turn irq_domain_add_linear() is called rather than
> >>    irq_domain_add_legacy(). This change could be avoided by providing an
> >>    irq_bases array to regmap_add_irq_chips().

> > This is a problem.

> OK, can you explain why? Is the problem the difference between the two
> types of IRQ domain? I would have assumed this was an internal detail of
> the driver hence not an issue. I assume there's no issue with
> known/static IRQ numbers, since both 0 and -1 end up dynamically
> allocating the IRQ bases IIRC.

We have GPIOs we might want to do interrupts on, if the API doesn't
support providing a base we've got an issue.

> >> 2) regmap_add_irq_chips() requests the top-level interrupt itself, so this
> >>    happens before the Arizona driver hooks the child BOOT_DONE and
> >>    CTRLIF_ERR interrupts. In the original, all the IRQ chips were created
> >>    first, and then the top-level IRQ was requested. This may cause a
> >>    functional difference if those interrupts are pending at probe() time.

> > Boot done is very likely to be asserted.

> Hmmm. Perhaps that means regmap_add_irq_chips() should be split into two
> parts; one to create all the IRQ chips and hook everything together, and
> the second to actually enable the interrupt.

That's what the existing arizona code does, it only requests the primary
IRQ line once it's completed setup.
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