linux-kernel - Re: [PATCH v5 2/5] dt-bindings: arm: msm: Convert kpss-acc driver Documentation to yaml

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Date:   Fri, 16 Sep 2022 23:22:17 +0300
From:   Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To:     Christian Marangi <ansuelsmth@...il.com>
Cc:     Rob Herring <robh@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Andy Gross <agross@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konrad.dybcio@...ainline.org>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Alexey Dobriyan <adobriyan@...il.com>,
        Takashi Iwai <tiwai@...e.de>,
        Christian Brauner <brauner@...nel.org>,
        Ranjani Sridharan <ranjani.sridharan@...ux.intel.com>,
        Marc Herbert <marc.herbert@...el.com>,
        James Smart <jsmart2021@...il.com>,
        Justin Tee <justin.tee@...adcom.com>,
        Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>,
        "Martin K. Petersen" <martin.petersen@...cle.com>,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-msm@...r.kernel.org, linux-clk@...r.kernel.org
Subject: Re: [PATCH v5 2/5] dt-bindings: arm: msm: Convert kpss-acc driver
 Documentation to yaml

On Fri, 16 Sept 2022 at 23:13, Christian Marangi <ansuelsmth@...il.com> wrote:
>
> On Fri, Sep 16, 2022 at 11:06:35PM +0300, Dmitry Baryshkov wrote:
> > On Fri, 16 Sept 2022 at 22:43, Christian Marangi <ansuelsmth@...il.com> wrote:
> > >
> > > On Fri, Sep 16, 2022 at 02:17:15PM -0500, Rob Herring wrote:
> > > > On Wed, Sep 14, 2022 at 04:22:53PM +0200, Christian Marangi wrote:
> > > > > Convert kpss-acc driver Documentation to yaml.
> > > > > The original Documentation was wrong all along. Fix it while we are
> > > > > converting it.
> > > > > The example was wrong as kpss-acc-v2 should only expose the regs but we
> > > > > don't have any driver that expose additional clocks. The kpss-acc driver
> > > > > is only specific to v1. For this exact reason, limit all the additional
> > > > > bindings (clocks, clock-names, clock-output-names and #clock-cells) to
> > > > > v1 and also flag that these bindings should NOT be used for v2.
> > > >
> > > > Odd that a clock controller has no clocks, but okay.
> > > >
> > >
> > > As said in the commit v2 is only used for regs. v2 it's only used in
> > > arch/arm/mach-qcom/platsmp.c to setup stuff cpu hotplug and bringup.
> > >
> > > Should we split the 2 driver? To me the acc naming seems to be just
> > > recycled for v2 and it's not really a clk controller.
> > >
> > > So keeping v2 in arm/msm/qcom,kpss-acc-v2.yaml and v1 moved to clock?
> >
> > I suspect that qcom,kpss-acc-v2 is misnamed as the "clock-controller".
> > According to msm-3.10, these regions are used by the Krait core
> > regulators.
> >
>
> Well we need to understand how to handle this... change the compatible
> it's a nono for sure. In platsmp.c they are used for cpu power control
> so could be that they are actually used to regulators. I would honestly
> move v1 to clock and leave v2 to arm/msm but I'm not cetain on what name
> to assign to the 2 yaml.
>
> What do you think?

This is fine for me. If somebody gets better understanding of
underlying hardware and works on actually using these blocks, he will
update the bindings.

My only suggestion would be to rename kpss-acc-v2 nodes to
'power-controller@...ress' and document them so.

-- 
With best wishes
Dmitry