Re: [PATCH] ARM: gic: Document Power and Clock Domain optional properties

From: Rob Herring
Date: Mon Apr 27 2015 - 11:26:01 EST


On Mon, Apr 27, 2015 at 10:00 AM, Geert Uytterhoeven
<geert+renesas@xxxxxxxxx> wrote:
> On some SoCs, the GIC may be part of a PM Domain (hardware Power and/or
> Clock Domain). Document the related optional DT properties.
>
> Note: As the current GIC driver doesn't support Runtime PM yet, PM
> Domain constraints must be handled elsewhere in e.g. platform code.
>
> Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>

Acked-by: Rob Herring <robh@xxxxxxxxxx>

One comment below.

> ---
> To preserve DT stability, we would like to add these properties to the
> affected shmobile dtsi files.
>
> On Thu, Mar 26, 2015 at 11:39 AM, Marc Zyngier <marc.zyngier@xxxxxxx> wrote:
>> On 25/03/15 21:19, Geert Uytterhoeven wrote:
>>> I would like to add the clock and GIC dependency on the clock in the DTS now,
>>> for reasons of DTS stability. But that means I need a temporary workaround
>>> to avoid the clock from being disabled, until the GIC driver handles this.
>>>
>>> I don't expect a fix for the GIC code to just show up magically. I just wanted
>>> you to be aware of the problem. GIC is not the only problematic module here,
>>> there are others, cfr. the last slide of [2].
>>
>> As long as there is an agreement from the DT people on the presence of
>> that extra property in the GIC node, I'm happy with that. I'd like it to
>> be documented though.
>
> Full thread at
> http://lists.infradead.org/pipermail/linux-arm-kernel/2015-March/331876.html
>
> Documentation/devicetree/bindings/arm/gic.txt | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/arm/gic.txt b/Documentation/devicetree/bindings/arm/gic.txt
> index 2da059a4790cb3c6..b21113b35f085f27 100644
> --- a/Documentation/devicetree/bindings/arm/gic.txt
> +++ b/Documentation/devicetree/bindings/arm/gic.txt
> @@ -58,6 +58,14 @@ Optional
> regions, used when the GIC doesn't have banked registers. The offset is
> cpu-offset * cpu-nr.
>
> +- power-domains : A phandle and PM domain specifier as defined by bindings of
> + the power controller specified by phandle, used when the GIC
> + is part of a Power or Clock Domain.

"or Clock" should be removed?

> +
> +- clocks : A phandle and clock specifier as defined by bindings of
> + the clock controller specified by phandle, used when the GIC
> + is part of a Clock Domain.
> +
> Example:
>
> intc: interrupt-controller@fff11000 {
> --
> 1.9.1
>
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