From: nm@ti•com (Nishanth Menon)
To: linux-arm-kernel@lists•infradead.org
Subject: [RFC] cpufreq-cpu0: allow OPP table supplied by platform
Date: Fri, 14 Mar 2014 10:36:27 -0500 [thread overview]
Message-ID: <532321FB.7080106@ti.com> (raw)
In-Reply-To: <20140314123205.GC813@S2101-09.ap.freescale.net>
On 03/14/2014 07:32 AM, Shawn Guo wrote:
> On Thu, Mar 13, 2014 at 07:44:24PM +0800, Jisheng Zhang wrote:
>>> On 13 March 2014 16:25, Viresh Kumar <viresh.kumar@linaro•org> wrote:
>>>> On 13 March 2014 16:18, Jisheng Zhang <jszhang@marvell•com> wrote:
>>>>> Hi all,
>>>>>
>>>>> cpufreq-cpu0 is suitable for Marvell Berlin SoC. But there's one issue
>>>>> to address. The opp is different between chips even on the same step
>>>>> SoC, BG2Q for example. we can calculate the OPP table from the value of
>>>>> one OTP register. We have two solutions:
>>>>>
>>>>> 1. bootloader reads OTP register and calculate the OPP table then change
>>>>> dtb danamically
>>>>>
>>>>> 2. supply one driver in mach-berlin to initialize the OPP table; and
>>>>> modify cpufreq-cpu0 to allow platform supply OPP table, fall back to
>>>>> of_init_opp_table() if there's no OPP table.
>>>>>
>>>>> Which solution is better?
>>>>
>>>> I think we can go ahead with second option here. We can just check if opp
>>>> tables are already initialized or not. In case they are, don't probe from
>>>> dt..
>>>>
>>>> But lets see with others have to say here..
>
> Yea, we had gone for the second option on imx6q-cpufreq driver with
> commit 20b7cbe (cpufreq: imx6q: add of_init_opp_table).
There might be a better alternative here given the scope of potential
reuse cross SoCs - a generic opp modifier logic which'd work for all
of us. I will let Dave Gerlach post his series to give an idea.
--
Regards,
Nishanth Menon
next prev parent reply other threads:[~2014-03-14 15:36 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20140313184859.7d6f6512@xhacker>
[not found] ` <CAKohpokLv0m+Cky7nCUOgP-djTMrA6jyka_EZ07+_exCAexXXg@mail.gmail.com>
[not found] ` <CAKohpoke1i8xmKProgF+ki7Q=Q+YxbPnewdtbyPqu7857DLLWA@mail.gmail.com>
2014-03-13 11:44 ` [RFC] cpufreq-cpu0: allow OPP table supplied by platform Jisheng Zhang
2014-03-13 17:43 ` Sören Brinkmann
2014-03-14 12:32 ` Shawn Guo
2014-03-14 15:36 ` Nishanth Menon [this message]
2014-03-14 19:32 ` Dave Gerlach
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