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From: Tim Bird <tbird20d@gmail.com>
To: Brian Norris <computersforpeace@gmail.com>
Cc: Rob Herring <robherring2@gmail.com>,
	Florian Fainelli <f.fainelli@gmail.com>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	Grant Likely <grant.likely@linaro.org>,
	Rob Herring <robh+dt@kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] of/irq: lookup 'interrupts-extended' property first
Date: Wed, 6 Aug 2014 14:50:47 -0700	[thread overview]
Message-ID: <CA+bK7J7LQq4S70ScSynbLTjNMmP=9n3KD2suYRg9JN+pEv-Y7g@mail.gmail.com> (raw)
In-Reply-To: <20140806201256.GO3711@ld-irv-0074>

On Wed, Aug 6, 2014 at 1:12 PM, Brian Norris
<computersforpeace@gmail.com> wrote:
> On Wed, Aug 06, 2014 at 01:42:08PM -0500, Rob Herring wrote:
>> On Wed, Aug 6, 2014 at 11:54 AM, Brian Norris <computersforpeace@gmail.com> wrote:
>> > On Thu, Jul 31, 2014 at 11:00:01AM -0700, Florian Fainelli wrote:
>> > I think it is important that a device tree provide some flexibility on
>> > kernel versions. We only invented 'interrupts-extended' in Linux 3.13,
>> > so it's easy to have device trees that could work only on 3.13+.
>> >
>> > Typically, we might say that new features require new kernels, but this
>> > is a very basic piece of the DT infrastructure. In our case, we have
>> > hardware whose basic features can be supported by a single interrupt
>> > parent, and so we used the 'interrupts' property pre-3.13. But when we
>> > want to add some power management features, there's an additional
>> > interrupt parent. Under the current DT binding, we have to switch over
>> > to using 'interrupts-extended' exclusively, and thus we must have a
>> > completely new DTB for >=3.13, and this DTB no longer works with the old
>> > kernels.
>>
>> "Must have" to enable the new features?
>
> Yes. The new feature requires an additional interrupt parent, and so it
> requires interrupts-extended.

Hold on there.  What about interrupt-map?  That was the traditional DT
feature for
supporting multi-parented interrupts.  Why couldn't the feature have been added
using that instead of interrupts-extended?

I know interrupts-extended is preferred, but has interrupt-map support been
removed from recent kernels?  I'm a bit confused.

 -- Tim Bird
Senior Software Engineer, Sony Mobile
Architecture Group Chair, CE Workgroup, Linux Foundation

WARNING: multiple messages have this Message-ID (diff)
From: Tim Bird <tbird20d-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
To: Brian Norris <computersforpeace-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: Rob Herring <robherring2-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	Florian Fainelli
	<f.fainelli-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	"devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
	<devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	Grant Likely
	<grant.likely-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>,
	Rob Herring <robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	"linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
	<linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Subject: Re: [PATCH] of/irq: lookup 'interrupts-extended' property first
Date: Wed, 6 Aug 2014 14:50:47 -0700	[thread overview]
Message-ID: <CA+bK7J7LQq4S70ScSynbLTjNMmP=9n3KD2suYRg9JN+pEv-Y7g@mail.gmail.com> (raw)
In-Reply-To: <20140806201256.GO3711@ld-irv-0074>

On Wed, Aug 6, 2014 at 1:12 PM, Brian Norris
<computersforpeace-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> On Wed, Aug 06, 2014 at 01:42:08PM -0500, Rob Herring wrote:
>> On Wed, Aug 6, 2014 at 11:54 AM, Brian Norris <computersforpeace-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
>> > On Thu, Jul 31, 2014 at 11:00:01AM -0700, Florian Fainelli wrote:
>> > I think it is important that a device tree provide some flexibility on
>> > kernel versions. We only invented 'interrupts-extended' in Linux 3.13,
>> > so it's easy to have device trees that could work only on 3.13+.
>> >
>> > Typically, we might say that new features require new kernels, but this
>> > is a very basic piece of the DT infrastructure. In our case, we have
>> > hardware whose basic features can be supported by a single interrupt
>> > parent, and so we used the 'interrupts' property pre-3.13. But when we
>> > want to add some power management features, there's an additional
>> > interrupt parent. Under the current DT binding, we have to switch over
>> > to using 'interrupts-extended' exclusively, and thus we must have a
>> > completely new DTB for >=3.13, and this DTB no longer works with the old
>> > kernels.
>>
>> "Must have" to enable the new features?
>
> Yes. The new feature requires an additional interrupt parent, and so it
> requires interrupts-extended.

Hold on there.  What about interrupt-map?  That was the traditional DT
feature for
supporting multi-parented interrupts.  Why couldn't the feature have been added
using that instead of interrupts-extended?

I know interrupts-extended is preferred, but has interrupt-map support been
removed from recent kernels?  I'm a bit confused.

 -- Tim Bird
Senior Software Engineer, Sony Mobile
Architecture Group Chair, CE Workgroup, Linux Foundation
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  reply	other threads:[~2014-08-06 21:50 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-06-19 23:33 [PATCH] of/irq: lookup 'interrupts-extended' property first Florian Fainelli
2014-07-31 18:00 ` Florian Fainelli
2014-07-31 18:00   ` Florian Fainelli
2014-08-06 16:54   ` Brian Norris
2014-08-06 18:42     ` Rob Herring
2014-08-06 18:42       ` Rob Herring
2014-08-06 20:12       ` Brian Norris
2014-08-06 21:50         ` Tim Bird [this message]
2014-08-06 21:50           ` Tim Bird
2014-08-06 22:12           ` Florian Fainelli
2014-08-06 22:12             ` Florian Fainelli
2014-08-15 12:56             ` Grant Likely
2014-08-06 22:24           ` Rob Herring

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