Messages in this thread | | | Date | Mon, 3 Nov 2014 10:25:37 -0800 | From | Brian Norris <> | Subject | Re: [PATCH] of/irq: Drop obsolete 'interrupts' vs 'interrupts-extended' text |
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On Mon, Nov 03, 2014 at 10:06:07AM -0800, Florian Fainelli wrote: > On 11/03/2014 02:15 AM, Mark Rutland wrote: > > On Sat, Nov 01, 2014 at 11:35:31PM +0000, Bjorn Helgaas wrote: > >> a9ecdc0fdc54 ("of/irq: Fix lookup to use 'interrupts-extended' property > >> first") updated the description to say that: > >> > >> - Both 'interrupts' and 'interrupts-extended' may be present > >> - Software should prefer 'interrupts-extended' > >> - Software that doesn't comprehend 'interrupts-extended' may use > >> 'interrupts' > >> > >> But there is still a paragraph at the end that prohibits having both and > >> says 'interrupts' should be preferred. > >> > >> Remove the contradictory text. > >> > >> Fixes: a9ecdc0fdc54 ("of/irq: Fix lookup to use 'interrupts-extended' property first") > >> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> > >> CC: stable@vger.kernel.org # v3.13+ > >> --- > >> .../bindings/interrupt-controller/interrupts.txt | 4 ---- > >> 1 file changed, 4 deletions(-) > >> > >> diff --git a/Documentation/devicetree/bindings/interrupt-controller/interrupts.txt b/Documentation/devicetree/bindings/interrupt-controller/interrupts.txt > >> index ce6a1a072028..8a3c40829899 100644 > >> --- a/Documentation/devicetree/bindings/interrupt-controller/interrupts.txt > >> +++ b/Documentation/devicetree/bindings/interrupt-controller/interrupts.txt > >> @@ -30,10 +30,6 @@ should only be used when a device has multiple interrupt parents. > >> Example: > >> interrupts-extended = <&intc1 5 1>, <&intc2 1 0>; > >> > >> -A device node may contain either "interrupts" or "interrupts-extended", but not > >> -both. If both properties are present, then the operating system should log an > >> -error and use only the data in "interrupts". > > > > Why not update the binding to explain that interrupts-extended is > > typically preferred? > > Does not the following: > > "Nodes that describe devices which generate interrupts must contain an > "interrupts" property, an "interrupts-extended" property, or both. If > both are > present, the latter should take precedence; the former may be provided > simply > for compatibility with software that does not recognize the latter." > > already makes it clear that 'interrupts-extended' is the preferred way > to represent interrupts?
I'm not sure I understand Mark's original question fully, because I'm not sure what he means by "typically preferred."
I wouldn't actually say that interrupts-extended is "preferred" in general. It should be "preferred" by the consumer of the device tree (e.g., Linux) because it is more descriptive. And that's what commit a9ecdc0fdc54aa ("of/irq: Fix lookup to use 'interrupts-extended' property first") was all about.
But when constructing a device tree, it actually makes sense to "prefer" the simplest possible description. So if you have a single interrupt parent, it makes sense to choose the existing ePAPR "interrupts" property.
Anyway, I agree with the principle of Florian's response; that the current documentation (minus the contradictory statement) is sufficient. But I'd point to this existing piece of the doc:
"interrupts-extended" should only be used when a device has multiple interrupt parents.
Brian
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