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Date:   Sat, 19 Aug 2023 22:19:03 +0200
From:   Andreas Kemnade <andreas@kemnade.info>
To:     Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Cc:     jic23@kernel.org, lars@metafoo.de, robh+dt@kernel.org,
        krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org,
        linux-iio@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-omap@vger.kernel.org
Subject: Re: [PATCH] dt-bindings: iio: adc: Add TI TWL603X GPADC
Message-ID: <20230819221903.726a1c39@aktux>
In-Reply-To: <426d78d6-9fa6-bfeb-b36a-fba264097a27@linaro.org>
References: <20230816202614.324457-1-andreas@kemnade.info>
        <426d78d6-9fa6-bfeb-b36a-fba264097a27@linaro.org>
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Hi,

On Sat, 19 Aug 2023 20:35:27 +0200
Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> wrote:

> On 16/08/2023 22:26, Andreas Kemnade wrote:
> > Document TI TWL603X GPADC devicetree bindings.
> > A driver is already there, the compatibles are used, but not documented.
> > Use two separate files to reference only the allowed compatible in
> > a future YAML version of
> > Documentation/devicetree/bindings/mfd/twl-family.txt
> > 
> > Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
> > ---  
> 
> Thank you for your patch. There is something to discuss/improve.
> 
> 
> >  .../bindings/iio/adc/ti,twl6030-gpadc.yaml    | 42 +++++++++++++++++++
> >  .../bindings/iio/adc/ti,twl6032-gpadc.yaml    | 42 +++++++++++++++++++
> >  2 files changed, 84 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/iio/adc/ti,twl6030-gpadc.yaml
> >  create mode 100644 Documentation/devicetree/bindings/iio/adc/ti,twl6032-gpadc.yaml
> > 
> > diff --git a/Documentation/devicetree/bindings/iio/adc/ti,twl6030-gpadc.yaml b/Documentation/devicetree/bindings/iio/adc/ti,twl6030-gpadc.yaml
> > new file mode 100644
> > index 000000000000..08bc0468f616
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/iio/adc/ti,twl6030-gpadc.yaml
> > @@ -0,0 +1,42 @@
> > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/iio/adc/ti,twl6030-gpadc.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: GPADC subsystem in the TWL6030 power module
> > +
> > +maintainers:
> > +  - Jonathan Cameron <jic23@kernel.org>  
> 
> This should be rather someone knowing or having or caring about this
> particular hardware, not subsystem maintainer.
> 
Hmm, I have the twl6032, but not the twl6030. So probably
Tony (OMAP-Maintainer) or me?

> > +
> > +description:
> > +  The GPADC subsystem in the TWL6030 consists of a 10-bit ADC
> > +  combined with a 15-input analog multiplexer.
> > +
> > +properties:
> > +  compatible:
> > +    const: ti,twl6030-gpadc  
> 
> Devices look fairly similar. Same properties. Why aren't they in one
> binding (enum here instead)?
>
I hope it can be done. See commit message. Maybe my reasoning is wrong.

So what I am thinking about:

&i2c {
	twl: pmic@48 {
		compatible = "ti,twl6032;
		adc {
			compatible = "ti,twl6032-gpadc";
		}
	}
}

So the idea was to later enforce that below a "ti,twl6032" no "ti,twl6030-gpadc"
is allowed in a future yaml version of mfd/twl-family.txt by
using a if: ... compatible = "twl,6032" .. $ref ti,twl6032-gpadc.yaml

If there are other possibilities or that can be just ignored for now,
I fully agree to your proposal. 

Regards,
Andreas