linux-kernel - Re: [PATCH v5 0/3] Add required-opps support to devfreq passive gov

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Message-ID: <CAJMQK-jaYTG_jRB1mfs8c1=NWM2bEAWhUUhjVTfGJ5fCR6dCkQ@mail.gmail.com>
Date:   Thu, 4 Feb 2021 16:12:01 +0800
From:   Hsin-Yi Wang <hsinyi@...omium.org>
To:     Viresh Kumar <viresh.kumar@...aro.org>
Cc:     Viresh Kumar <vireshk@...nel.org>,
        Linux PM <linux-pm@...r.kernel.org>,
        Nishanth Menon <nm@...com>, Stephen Boyd <sboyd@...nel.org>,
        "Rafael J . Wysocki" <rjw@...ysocki.net>,
        lkml <linux-kernel@...r.kernel.org>,
        "MyungJoo Ham )" <myungjoo.ham@...sung.com>,
        Kyungmin Park <kyungmin.park@...sung.com>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        Saravana Kannan <saravanak@...gle.com>
Subject: Re: [PATCH v5 0/3] Add required-opps support to devfreq passive gov

On Thu, Feb 4, 2021 at 1:41 PM Viresh Kumar <viresh.kumar@...aro.org> wrote:
>
> On 03-02-21, 17:23, Hsin-Yi Wang wrote:
> > The devfreq passive governor scales the frequency of a "child" device based
> > on the current frequency of a "parent" device (not parent/child in the
> > sense of device hierarchy). As of today, the passive governor requires one
> > of the following to work correctly:
> > 1. The parent and child device have the same number of frequencies
> > 2. The child device driver passes a mapping function to translate from
> >    parent frequency to child frequency.
> >
> > When (1) is not true, (2) is the only option right now. But often times,
> > all that is required is a simple mapping from parent's frequency to child's
> > frequency.
> >
> > Since OPPs already support pointing to other "required-opps", add support
> > for using that to map from parent device frequency to child device
> > frequency. That way, every child device driver doesn't have to implement a
> > separate mapping function anytime (1) isn't true.
>
> So you guys aren't interested in dev_pm_opp_set_opp() but just the
> translation of the required-OPPs ?
>
I think this series focuses on required-opps.

> I am fine with most of the stuff and I would like to take it via OPP
> tree, hope that would be fine ?
>
Sounds good to me, thanks.

> --
> viresh