From mboxrd@z Thu Jan  1 00:00:00 1970
From: Rob Herring <robh@kernel.org>
Subject: Re: [PATCH 1/2] PM / Domains: Define DT bindings for PM QoS device
 latencies
Date: Fri, 1 Apr 2016 13:44:29 -0500
Message-ID: <20160401184429.GA18950@rob-hp-laptop>
References: <1459432226-22562-1-git-send-email-ulf.hansson@linaro.org>
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To: Ulf Hansson <ulf.hansson@linaro.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>, Kevin Hilman <khilman@kernel.org>, linux-pm@vger.kernel.org, Len Brown <len.brown@intel.com>, Pavel Machek <pavel@ucw.cz>, Geert Uytterhoeven <geert+renesas@glider.be>, Lina Iyer <lina.iyer@linaro.org>, Axel Haslam <ahaslam@baylibre.com>, Marek Szyprowski <m.szyprowski@samsung.com>, Jon Hunter <jonathanh@nvidia.com>, devicetree@vger.kernel.org
List-Id: devicetree@vger.kernel.org

On Thu, Mar 31, 2016 at 03:50:25PM +0200, Ulf Hansson wrote:
> PM QoS device latencies are properties of the hardware. Let's define some
> DT bindings for them.
> 
> Suggested-by: Geert Uytterhoeven <geert+renesas@glider.be>
> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
> ---
>  Documentation/devicetree/bindings/power/power_domain.txt | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/power/power_domain.txt b/Documentation/devicetree/bindings/power/power_domain.txt
> index 025b5e7..b101a20 100644
> --- a/Documentation/devicetree/bindings/power/power_domain.txt
> +++ b/Documentation/devicetree/bindings/power/power_domain.txt
> @@ -65,12 +65,18 @@ Required properties:
>   - power-domains : A phandle and PM domain specifier as defined by bindings of
>                     the power controller specified by phandle.
>  
> +Optional properties:
> + - suspend-latency: Suspend latency of the device in ns.
> + - resume-latency: Resume latency of the device in ns.

The names are a bit Linux specific, but I don't have a better 
suggestion. Could be power-up/down, but then you may have other 
latencies such as link up times.

Whatever we end up with, add a unit suffix (-ns).

Shouldn't this be split into latency of the domain (and in the domain's 
node) and latency of the device? 

> +
>  Example:
>  
>  	leaky-device@12350000 {
>  		compatible = "foo,i-leak-current";
>  		reg = <0x12350000 0x1000>;
>  		power-domains = <&power 0>;
> +		suspend-latency = <250000>;
> +		resume-latency = <250000>;
>  	};
>  
>  The node above defines a typical PM domain consumer device, which is located
> -- 
> 1.9.1
> 
> --
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