Re: [PATCH 2/6] ARM: Tegra: Add CPU's OPPs for using cpufreq-cpu0 driver

Nishanth Menon
2013-08-08T15:52:57Z

On Thu, Aug 8, 2013 at 9:37 AM, Viresh Kumar <viresh.kumar@linaro.org> wrote:
> On 8 August 2013 19:52, Lucas Stach <l.stach@pengutronix.de> wrote:
>> You can certainly define the mapping table in DT where a specialized
>> Tegra cpufreq driver could read it in and then map frequency to voltage.
>> But that's a runtime decision, as Speedo and process ID are fuse values
>> and can not be represented in DT.
>
>> The problem with this is that the hardware description now associates
>> voltages with certain frequencies and even if they are not used by the
>> Linux driver they are plain wrong.
>
> Hmm. I understand.
> Then we probably need mach-tegra/opp.c to call opp_add() for all such
> OPPs.. Neither DT nor cpufreq driver are the right place for this.

This is similar to what I suspected might be the case on other
platforms (in addition to known iMx and OMAP). Could you see/comment
on [1] to see if it meets your needs.

We should like to avoid dealing custom SoC specific OPP, if we are
able to generalize the need. ofcourse, I am yet to submit a official
proposal, but more SoCs the current proposal can handle, the better it
will be for all of us.

[1] http://marc.info/?l=linux-pm&m=137589225305971&w=2
--
Regards,
Nishanth Menon