linux-kernel - Re: [PATCH v3 2/3] iio: pressure: Add driver for Sensirion SDP500

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Message-ID: <CADFWO8FF24UyoD9cfF5NL1OzcHErx8+=bJYLrajrJNHFseK2HQ@mail.gmail.com>
Date: Thu, 4 Jul 2024 09:49:45 +0200
From: Petar Stoykov <pd.pstoykov@...il.com>
To: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
Cc: linux-iio@...r.kernel.org, Jonathan Cameron <jic23@...nel.org>, 
	Lars-Peter Clausen <lars@...afoo.de>, Rob Herring <robh+dt@...nel.org>, 
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>, Conor Dooley <conor+dt@...nel.org>, 
	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>, devicetree@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 2/3] iio: pressure: Add driver for Sensirion SDP500

On Tue, Jul 2, 2024 at 5:17 PM Krzysztof Kozlowski
<krzysztof.kozlowski@...aro.org> wrote:
>
> On 02/07/2024 16:59, Petar Stoykov via B4 Relay wrote:
> > From: Petar Stoykov <pd.pstoykov@...il.com>
> >
> > Sensirion SDP500 is a digital differential pressure sensor. The sensor is
> > accessed over I2C.
> >
>
> ...
>
> > +
> > +static const struct of_device_id sdp500_of_match[] = {
> > +     { .compatible = "sensirion,sdp500" },
> > +     { .compatible = "sensirion,sdp510" },
>
> Devices look compatible, so express it in the bindings with fallback to
> sdp500 (oneOf, see example-schema).

Hi Krzysztof,
I tried to understand the explanation in the example-schema. I must say it is
a bit confusing, but I can't offer improvement because I'm not sure I
understand it fully yet.
Can you verify if this is what you expect the bindings file to read?
properties:
  compatible:
    oneOf:
      - items:
        - const: sensirion,sdp510
        - const: sensirion,sdp500
      - items:
        - const: sensirion,sdp500

So the device tree should have either this
  compatible = "sensirion,sdp510", "sensirion,sdp500"
Or
  compatible = "sensirion,sdp500"
The first would mean that 510 falls back to 500, right?

>From what I've seen it is rare to have two strings in "compatible" so I didn't
know of this mechanism of "fallback" in the dts. I expected to just write the
name of my device (let's say "sensirion,sdp510") and the driver would handle it.
But I'm learning. Expectations change.

Regards,
Petar

>
> Best regards,
> Krzysztof
>