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Date: Wed, 07 Jan 2009 16:23:53 -0600
From: Scott Wood <scottwood@freescale.com>
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To: Grant Likely <grant.likely@secretlab.ca>
Subject: Re: [PATCH 2/5] powerpc: Generic device tree for all AmigaOne boards
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Grant Likely wrote:
> On Wed, Jan 7, 2009 at 3:10 PM, Scott Wood <scottwood@freescale.com> wrote:
>> On Wed, Jan 07, 2009 at 09:41:14AM -0700, Grant Likely wrote:
>>>> +                       8042@60 {
>>>> +                               device_type = "8042";
>>>> +                               reg = <1 0x00000060 0x00000001
>>>> +                                      1 0x00000064 0x00000001>;
>>>> +                               // IRQ1, IRQ12 (rising edge)
>>>> +                               interrupts = <1 3 12 3>;
>>> For the flattened device tree, I think we've settled on the convention
>>> that every node with an IRQ connection should have both the
>>> interrupt-parent and interrupts properties.  (ie. don't rely on the
>>> parent node's interrupt-parent property.)
>> Why?
> 
> Defensive programming.  To not rely on implicit relationships

It doesn't seem any more likely to introduce a fault by specifying the 
interrupt controller in one place than in many places.

-Scott