Date: Tue, 26 Dec 2017 14:29:55 -0600
From: Rob Herring <robh@kernel.org>
To: Viresh Kumar <viresh.kumar@linaro.org>
Cc: ulf.hansson@linaro.org, Kevin Hilman <khilman@kernel.org>,
        Viresh Kumar <vireshk@kernel.org>, Nishanth Menon <nm@ti.com>,
        Stephen Boyd <sboyd@codeaurora.org>,
        Rafael Wysocki <rjw@rjwysocki.net>, linux-pm@vger.kernel.org,
        Vincent Guittot <vincent.guittot@linaro.org>, rnayak@codeaurora.org,
        sudeep.holla@arm.com, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH V8 3/3] OPP: Allow "opp-hz" and "opp-microvolt" to
 contain magic values
Message-ID: <20171226202955.32j7gzonrixtwdpt@rob-hp-laptop>
References: <cover.1513591822.git.viresh.kumar@linaro.org>
 <476d7ae69184d787ccc6d99f8df6069007fd0a91.1513591822.git.viresh.kumar@linaro.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <476d7ae69184d787ccc6d99f8df6069007fd0a91.1513591822.git.viresh.kumar@linaro.org>
User-Agent: NeoMutt/20170609 (1.8.3)
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1470
Lines: 33

On Mon, Dec 18, 2017 at 03:51:30PM +0530, Viresh Kumar wrote:
> On some platforms the exact frequency or voltage may be hidden from the
> OS by the firmware. Allow such configurations to pass magic values in
> the "opp-hz" or the "opp-microvolt" properties, which should be
> interpreted in a platform dependent way.
> 
> Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
> ---
>  Documentation/devicetree/bindings/opp/opp.txt | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/opp/opp.txt b/Documentation/devicetree/bindings/opp/opp.txt
> index 4e4f30288c8b..00a3bdbd0f1f 100644
> --- a/Documentation/devicetree/bindings/opp/opp.txt
> +++ b/Documentation/devicetree/bindings/opp/opp.txt
> @@ -167,6 +167,12 @@ properties.
>    functioning of the current device at the current OPP (where this property is
>    present).
>  
> +
> +On some platforms the exact frequency or voltage may be hidden from the OS by
> +the firmware and the "opp-hz" or the "opp-microvolt" properties may contain
> +magic values that represent the frequency or voltage in a firmware dependent
> +way, for example an index of an array in the firmware.

I'm still not convinced this is a good idea. If you have firmware 
partially managing things, then I think we should have platform specific 
bindings or drivers. 

This is complex enough I'm not taking silence from Stephen as an okay.

Rob