Messages in this thread | | | Subject | Re: [PATCH v2 1/2] dt-bindings: staging: iio: cdc: ad7746: add binding documentation for AD7746 | From | Lars-Peter Clausen <> | Date | Thu, 22 Apr 2021 22:56:38 +0200 |
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On 4/22/21 9:16 PM, Lucas Stankus wrote: > On Tue, Apr 20, 2021 at 4:37 PM 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. >> >>> [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'. > Thanks for the feedback! > From reading the data sheet I couldn't quite grasp what would be an inverted > excitation output, but I don't have a lot of experience with CDCs. Maybe someone > with more experience could help out with a better suggestion.
This is the only thing I could find https://www.analog.com/media/en/technical-documentation/application-notes/AN-1585.pdf.
The datasheet also says that only at most one of them should be inverted. So maybe only a single property which selects which of the two is inverted.
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