Re: [PATCH 1/3] PM / OPP: Add support for descending order for cpufreq table

From: Viresh Kumar <viresh.kumar@linaro.org>
To: Nishanth Menon <nm@ti.com>
Cc: Jonghwan Choi <jhbird.choi@samsung.com>,
	Linux PM list <linux-pm@vger.kernel.org>,
	open list <linux-kernel@vger.kernel.org>,
	"Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Len Brown <len.brown@intel.com>,
	Amit Daniel Kachhap <amit.daniel@samsung.com>
Subject: Re: [PATCH 1/3] PM / OPP: Add support for descending order for cpufreq table
Date: Mon, 5 May 2014 19:44:48 +0530	[thread overview]
Message-ID: <CAKohpon-KZpSJK7PxpLjZS7sVPcYraDxb4oJHN6dxSagD+F--Q@mail.gmail.com> (raw)
In-Reply-To: <5367946F.1030407@ti.com>

On 5 May 2014 19:08, Nishanth Menon <nm@ti.com> wrote:
> With the brief history of the patch in linux-pm, I am unable to
> understand why not just use ceil/floor routines to pick up data the
> way you need it. It should not matter if we use an ordered list, or
> some other weird organization inside the storage. There are already
> accessors functions meant to precisely help with the case that is
> being tried here.

To be precise, for exynos they need the position of a frequency when
it is arranged in descending order. And they will simply write this position
in their clock controller later. For example, if frequencies are:
100 MHz, 200, 300, 400, 500, 600

Then they need to write 1 for 600, 2 for 500, 3 for 400, and so on..
I am not able to imaging how ceil/floor would help here.