Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Mon, 1 May 2023 16:39:20 +0100
From:   Jonathan Cameron <jic23@kernel.org>
To:     Herve Codina <herve.codina@bootlin.com>
Cc:     Lars-Peter Clausen <lars@metafoo.de>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        linux-iio@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Christophe Leroy <christophe.leroy@csgroup.eu>,
        Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Subject: Re: [PATCH v3 1/3] dt-bindings: iio: potentiometer: Add the Renesas
 X9250 potentiometers
Message-ID: <20230501163920.65cc9454@jic23-huawei>
In-Reply-To: <20230424090318.4750a5e7@bootlin.com>
References: <20230421085245.302169-1-herve.codina@bootlin.com>
        <20230421085245.302169-2-herve.codina@bootlin.com>
        <20230422171807.510d7fa3@jic23-huawei>
        <20230424090318.4750a5e7@bootlin.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Precedence: bulk

On Mon, 24 Apr 2023 09:03:18 +0200
Herve Codina <herve.codina@bootlin.com> wrote:

> Hi Jonathan, Krzysztof,
> 
> On Sat, 22 Apr 2023 17:18:07 +0100
> Jonathan Cameron <jic23@kernel.org> wrote:
> 
> > On Fri, 21 Apr 2023 10:52:43 +0200
> > Herve Codina <herve.codina@bootlin.com> wrote:
> >   
> > > The Renesas X9250 is a quad digitally controlled potentiometers.
> > > 
> > > Signed-off-by: Herve Codina <herve.codina@bootlin.com>    
> > 
> > Hi Herve,
> > 
> > Historically we've been a bit lax in IIO bindings in always making
> > sure the per supplies are included.  As a result we frequently get
> > them added later and it just makes things messier than they should
> > be.
> > 
> > So please add vcc-supply from the start.  V+ and V- are a little trickier.
> > I was expecting datasheet to say they should be symmetric about 0 but it
> > doesn't. So they could be two independent supplies.
> > 
> > Also make it required as my current understanding is that we should
> > do that for supplies that are definitely present even if we could
> > rely on the fallback to regulator stubs if they aren't supplied.
> > So add the 3 supplies to required as well.  
> 
> Yes, I will add the following supplies in the next iteration:
>  - 'vcc-supply' for VCC
>  - 'avp-supply' for the analog V+
>  - 'avn-supply' for the analog V-
> 
> and add them in the required list of properties.
> 
> Are the names correct for these power supplies (avp and avn) ?

I think so.  I'm not totally sure on how DT maintainers think we should deal
with a two voltage level reference though.  Perhaps add some description to
make it very clear what is going on and we'll see what review comments we get!

Jonathan