linux-kernel - Re: [PATCH v4 1/2] regulator: dt-bindings: add QCOM RPMh regulator bindings

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Date:   Wed, 30 May 2018 09:12:25 -0700
From:   Doug Anderson <dianders@...omium.org>
To:     Mark Brown <broonie@...nel.org>
Cc:     David Collins <collinsd@...eaurora.org>,
        Liam Girdwood <lgirdwood@...il.com>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        linux-arm-msm@...r.kernel.org,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        devicetree@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>,
        Rajendra Nayak <rnayak@...eaurora.org>,
        Stephen Boyd <sboyd@...nel.org>
Subject: Re: [PATCH v4 1/2] regulator: dt-bindings: add QCOM RPMh regulator bindings

Hi,

On Wed, May 30, 2018 at 8:50 AM, Mark Brown <broonie@...nel.org> wrote:
> On Wed, May 30, 2018 at 07:54:47AM -0700, Doug Anderson wrote:
>> On Wed, May 30, 2018 at 3:37 AM, Mark Brown <broonie@...nel.org> wrote:
>
>> > I'm confused as to why we are specifying the maximum current the device
>> > can deliver in a given mode in the DT - surely that's a fixed property
>> > of the hardware?
>
>> Said another way: you're saying that you'd expect the "max-microamps"
>> table to have one fewer element than the listed modes?  So in the
>> above example you'd have:
>
> No, I'm saying that I don't know why that property exists at all.  This
> sounds like it's intended to be the amount of current the regulator can
> deliver in each mode which is normally a design property of the silicon.

Ah, got it.  So the whole point here is to be able to implement either
the function "set_load" or the function "get_optimum_mode".  We need
some sort of table to convert from current to mode.  That's what this
table does.

My argument to David was that since set_load / get_optimum_mode were
features of the regulator core these should actually be standard
properties and not Qualcomm-specific ones.

-Doug