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Date:   Sat, 24 Apr 2021 12:54:59 +0100
From:   Jonathan Cameron <jic23@kernel.org>
To:     Rob Herring <robh@kernel.org>
Cc:     Lucas Stankus <lucas.p.stankus@gmail.com>, lars@metafoo.de,
        Michael.Hennerich@analog.com, gregkh@linuxfoundation.org,
        linux-iio@vger.kernel.org, linux-staging@lists.linux.dev,
        linux-kernel@vger.kernel.org, devicetree@vger.kernel.org
Subject: Re: [PATCH v2 1/2] dt-bindings: staging: iio: cdc: ad7746: add
 binding documentation for AD7746
Message-ID: <20210424125459.48cd2886@jic23-huawei>
In-Reply-To: <20210420193746.GA3632576@robh.at.kernel.org>
References: <cover.1618785336.git.lucas.p.stankus@gmail.com>
        <54a9eaeaa42d47037b2a07bd933e6dfade745d02.1618785336.git.lucas.p.stankus@gmail.com>
        <20210420193746.GA3632576@robh.at.kernel.org>
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On Tue, 20 Apr 2021 14:37:46 -0500
Rob Herring <robh@kernel.org> wrote:

> On Sun, Apr 18, 2021 at 07:49:51PM -0300, Lucas Stankus wrote:
> > Add device tree binding documentation for AD7746 cdc in YAML format.
> > 
> > Signed-off-by: Lucas Stankus <lucas.p.stankus@gmail.com>
> > ---
> > 
> > A minor note about the adi,excitation-vdd-permille property. Jonathan
> > suggested the name to be adi,excitation-vdd-milicent, but I was unsure of
> > the milicent naming. With a quick search I found out that the common way to
> > call a thousandth is 'per mille'[1], but I didn't find any use of it in the
> > kernel documentation. Any thoughts about it?  
> 
> Seems okay to me.

Sorry about that.  I realised later in the day I was talking garbage, but
forgot to send a reply to say that when I was next on my computer :(
permille was what I mean.

> 
> > [1] https://en.wikipedia.org/wiki/Per_mille
> > 
> >  .../bindings/iio/cdc/adi,ad7746.yaml          | 73 +++++++++++++++++++
> >  1 file changed, 73 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/iio/cdc/adi,ad7746.yaml
> > 
> > diff --git a/Documentation/devicetree/bindings/iio/cdc/adi,ad7746.yaml b/Documentation/devicetree/bindings/iio/cdc/adi,ad7746.yaml
> > new file mode 100644
> > index 000000000000..a2a7eee674ba
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/iio/cdc/adi,ad7746.yaml
> > @@ -0,0 +1,73 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/iio/cdc/adi,ad7746.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: AD7746 24-Bit Capacitance-to-Digital Converter with Temperature Sensor
> > +
> > +maintainers:
> > +  - Michael Hennerich <michael.hennerich@analog.com>
> > +
> > +description: |
> > +  AD7746 24-Bit Capacitance-to-Digital Converter with Temperature Sensor
> > +
> > +  Specifications about the part can be found at:
> > +  https://www.analog.com/media/en/technical-documentation/data-sheets/ad7291.pdf
> > +
> > +properties:
> > +  compatible:
> > +    enum:
> > +      - adi,ad7745
> > +      - adi,ad7746
> > +      - adi,ad7747
> > +
> > +  reg:
> > +    maxItems: 1
> > +
> > +  adi,excitation-vdd-permille:
> > +    description: |
> > +      Set VDD per mille to be used as the excitation voltage.
> > +    $ref: /schemas/types.yaml#/definitions/uint32
> > +    enum: [125, 250, 375, 500]
> > +
> > +  adi,exca-output-en:
> > +    description: Enables the EXCA pin as the excitation output.
> > +    type: boolean
> > +
> > +  adi,exca-output-invert:
> > +    description: Inverts the excitation output in the EXCA pin.
> > +    type: boolean  
> 
> 'invert' assumes I know what the non-inverted signal is. Sometimes that 
> makes sense, but if you can define in terms of the inverse that would be 
> better. For example, for a normally active low signal, name the property 
> 'foo-active-high'.
> 
> > +
> > +  adi,excb-output-en:
> > +    description: Enables the EXCB pin as the excitation output.
> > +    type: boolean
> > +
> > +  adi,excb-output-invert:
> > +    description: Inverts the excitation output in the EXCB pin.
> > +    type: boolean
> > +
> > +required:
> > +  - compatible
> > +  - reg
> > +
> > +additionalProperties: false
> > +
> > +examples:
> > +  - |
> > +    i2c {
> > +      #address-cells = <1>;
> > +      #size-cells = <0>;
> > +
> > +      ad7746: cdc@48 {
> > +        compatible = "adi,ad7746";
> > +        reg = <0x48>;
> > +        adi,excitation-vdd-permille = <125>;
> > +
> > +        adi,exca-output-en;
> > +        adi,exca-output-invert;
> > +        adi,excb-output-en;
> > +        adi,excb-output-invert;
> > +      };
> > +    };
> > +...
> > -- 
> > 2.31.1
> >