linux-kernel - Re: [PATCH 3/3] regulator: dt-bindings: qcom,rpmh: Indicate regulator-allow-set-load dependencies

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Message-ID: <20220906144117.wyqulotg52aqru7u@halaneylaptop>
Date:   Tue, 6 Sep 2022 09:41:17 -0500
From:   Andrew Halaney <ahalaney@...hat.com>
To:     Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
Cc:     agross@...nel.org, andersson@...nel.org,
        konrad.dybcio@...ainline.org, lgirdwood@...il.com,
        broonie@...nel.org, robh+dt@...nel.org,
        krzysztof.kozlowski+dt@...aro.org, linux-arm-msm@...r.kernel.org,
        linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
        dianders@...omium.org, johan@...nel.org
Subject: Re: [PATCH 3/3] regulator: dt-bindings: qcom,rpmh: Indicate
 regulator-allow-set-load dependencies

On Mon, Sep 05, 2022 at 06:50:02PM +0200, Krzysztof Kozlowski wrote:
> On 02/09/2022 20:51, Andrew Halaney wrote:
> > For RPMH regulators it doesn't make sense to indicate
> > regulator-allow-set-load without saying what modes you can switch to,
> > so be sure to indicate a dependency on regulator-allowed-modes.
> 
> Hmmmm.... What about other regulators?
> 

My understanding (which very well might be wrong) is that if your
regulator is allowed to change modes, and sets regulator-allow-set-load,
then you have to describe what modes you can switch to.

But if you don't allow setting modes (for example qcom_rpm-regulator.c)
and just allow yourself to set_load() directly, then you don't need it.

So there is a more general requirement that applies regulator wide, but
I'm not sure how you would apply that at a higher level. I don't see a
good way to figure out in dt-binding land what regulator ops each
binding supports.

Hope that makes sense,
Andrew

> > 
> > With this in place devicetree validation can catch issues like this:
> > 
> >     /mnt/extrassd/git/linux-next/arch/arm64/boot/dts/qcom/sm8350-hdk.dtb: pm8350-rpmh-regulators: ldo5: 'regulator-allowed-modes' is a dependency of 'regulator-allow-set-load'
> >             From schema: /mnt/extrassd/git/linux-next/Documentation/devicetree/bindings/regulator/qcom,rpmh-regulator.yaml
> > 
> > Suggested-by: Johan Hovold <johan@...nel.org>
> > Signed-off-by: Andrew Halaney <ahalaney@...hat.com>
> 
> 
> Best regards,
> Krzysztof
>