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Date: Sun, 19 May 2024 13:33:11 +0100
From: Jonathan Cameron <jic23@kernel.org>
To: Conor Dooley <conor@kernel.org>
Cc: Gustavo Silva <gustavograzs@gmail.com>, robh@kernel.org,
 krzk+dt@kernel.org, conor+dt@kernel.org, lars@metafoo.de,
 christophe.jaillet@wanadoo.fr, gerald.loacker@wolfvision.net,
 devicetree@vger.kernel.org, linux-iio@vger.kernel.org,
 linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/6] dt-bindings: Add ENS160 as trivial device
Message-ID: <20240519133311.3752bb58@jic23-huawei>
In-Reply-To: <20240513-entree-ferris-cbaf7c57b0b5@spud>
References: <20240512210444.30824-1-gustavograzs@gmail.com>
	<20240512210444.30824-3-gustavograzs@gmail.com>
	<20240513-entree-ferris-cbaf7c57b0b5@spud>
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On Mon, 13 May 2024 17:09:46 +0100
Conor Dooley <conor@kernel.org> wrote:

> On Sun, May 12, 2024 at 06:04:38PM -0300, Gustavo Silva wrote:
> > ScioSense ENS160 is a multi-gas sensor.
> > 
> > Signed-off-by: Gustavo Silva <gustavograzs@gmail.com>  
> 
> Looks like this device has two supplies, Vdd and Vddio.
> Jonathan generally likes supplies to be documented, so that would
> disqualify this as a trivial device.

Agreed. History here is that we have put lots of IIO supported
devices in trivial-devices in the past and then it's turned out
someone has them on a board where they are controllable supplies.
So we end up having introduced insufficient binding docs + need
to move it later.

Much better to just have them documented from the start + just
turn them on at driver probe and off at remove (relying on regulator
subsystem support for fake supplies / fixed regulators where these
operations do nothing).  If someone wants to later do better power
control then that can be added without adding to the binding.

Jonathan

> 
> Cheers,
> Conor.
> 
> > ---
> >  Documentation/devicetree/bindings/trivial-devices.yaml | 2 ++
> >  1 file changed, 2 insertions(+)
> > 
> > diff --git a/Documentation/devicetree/bindings/trivial-devices.yaml b/Documentation/devicetree/bindings/trivial-devices.yaml
> > index e07be7bf8..cdd7f0b46 100644
> > --- a/Documentation/devicetree/bindings/trivial-devices.yaml
> > +++ b/Documentation/devicetree/bindings/trivial-devices.yaml
> > @@ -318,6 +318,8 @@ properties:
> >            - samsung,24ad0xd1
> >              # Samsung Exynos SoC SATA PHY I2C device
> >            - samsung,exynos-sataphy-i2c
> > +            # ScioSense ENS160 multi-gas sensor
> > +          - sciosense,ens160
> >              # Semtech sx1301 baseband processor
> >            - semtech,sx1301
> >              # Sensirion multi-pixel gas sensor with I2C interface
> > -- 
> > 2.45.0
> >