From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-14.0 required=3.0 tests=BAYES_00,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E4EA2C4743E for ; Fri, 4 Jun 2021 21:17:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C66CF613EC for ; Fri, 4 Jun 2021 21:17:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230127AbhFDVSx (ORCPT ); Fri, 4 Jun 2021 17:18:53 -0400 Received: from mail-ot1-f48.google.com ([209.85.210.48]:42912 "EHLO mail-ot1-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229665AbhFDVSw (ORCPT ); Fri, 4 Jun 2021 17:18:52 -0400 Received: by mail-ot1-f48.google.com with SMTP id w23-20020a9d5a970000b02903d0ef989477so6000956oth.9; Fri, 04 Jun 2021 14:17:05 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=MG5KxgxX2V167Mxk01FiCjyeRCj/anSLT1f7uYJ6gGc=; b=eVhxq1nW+nMTogWSjAGeKX9j2oFOXBNvjChav6ynKJRF8fbCIWH15inah+qiPBEve+ uaLyC+shF3aOpqn65X/jXxK05VEHXNAUbsI9FFxVcx2jRfZbSytkuTarKrT6pdiLsyE6 A7hW6CJ+dyPAExkdkBE9FVrXhnxZTlJMcC/AAwXqB/JpGrJigVHSlyDo4bVeczSAEAwA TJYX8QzC2BPqGxwKZ2ek1V6i/8B3b17ePU7fsDbTSI/nCgVs3eR+hwbXhox8bsvHF5vP n8zKCZk/BxTjEwQVTwAXy8JnCaA3totosBOoQXbd3344Mkfq7gqompR8xHIq4Sv3cc3q vyBQ== X-Gm-Message-State: AOAM53162vGHNgvU/ToVi/XiajK6gkPqpv8inGOzj6i3Uh3fsr8ML31u +RYonwszNPZvJ8osims+zg== X-Google-Smtp-Source: ABdhPJzgiyxpTp9buLL/uBcm5ExFupjA7/fgJketo2exschqxCHyZdbZ5cx6LZ8V3NJLSEEC4CSNAQ== X-Received: by 2002:a05:6830:1518:: with SMTP id k24mr5131330otp.40.1622841424250; Fri, 04 Jun 2021 14:17:04 -0700 (PDT) Received: from robh.at.kernel.org (24-155-109-49.dyn.grandenetworks.net. [24.155.109.49]) by smtp.gmail.com with ESMTPSA id x24sm712328otq.34.2021.06.04.14.17.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 04 Jun 2021 14:17:03 -0700 (PDT) Received: (nullmailer pid 3933507 invoked by uid 1000); Fri, 04 Jun 2021 21:17:02 -0000 Date: Fri, 4 Jun 2021 16:17:02 -0500 From: Rob Herring To: Liam Beguin Cc: peda@axentia.se, jic23@kernel.org, lars@metafoo.de, pmeerw@pmeerw.net, linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org, devicetree@vger.kernel.org Subject: Re: [PATCH v1 7/9] dt-bindings: iio: afe: add binding for temperature-sense-rtd Message-ID: <20210604211702.GA3925041@robh.at.kernel.org> References: <20210530005917.20953-1-liambeguin@gmail.com> <20210530005917.20953-8-liambeguin@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210530005917.20953-8-liambeguin@gmail.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, May 29, 2021 at 08:59:15PM -0400, Liam Beguin wrote: > From: Liam Beguin > > An ADC is often used to measure other quantities indirectly. This > binding describe one cases, the measurement of a temperature through > the voltage across an RTD resistor such as a PT1000. > > Signed-off-by: Liam Beguin > --- > .../iio/afe/temperature-sense-rtd.yaml | 65 +++++++++++++++++++ > MAINTAINERS | 1 + > 2 files changed, 66 insertions(+) > create mode 100644 Documentation/devicetree/bindings/iio/afe/temperature-sense-rtd.yaml > > diff --git a/Documentation/devicetree/bindings/iio/afe/temperature-sense-rtd.yaml b/Documentation/devicetree/bindings/iio/afe/temperature-sense-rtd.yaml > new file mode 100644 > index 000000000000..4798eda6e533 > --- /dev/null > +++ b/Documentation/devicetree/bindings/iio/afe/temperature-sense-rtd.yaml > @@ -0,0 +1,65 @@ > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause) > +%YAML 1.2 > +--- > +$id: http://devicetree.org/schemas/iio/afe/temperature-sense-rtd.yaml# > +$schema: http://devicetree.org/meta-schemas/core.yaml# > + > +title: Temperature Sense RTD > + > +maintainers: > + - Liam Beguin > + > +description: | > + When an io-channel measures the output voltage across an RTD such as a What's an RTD? Not defined anywhere here. > + PT1000, the interesting measurement is almost always the corresponding > + temperature, not the voltage output. This binding describes such a circuit. > + > +properties: > + compatible: > + const: temperature-sense-rtd > + > + io-channels: > + maxItems: 1 > + description: | > + Channel node of a voltage io-channel. > + > + '#io-channel-cells': > + const: 1 Doesn't this belong in the provider? > + > + excitation-current-microamp: > + description: The current fed through the RTD sensor. > + > + alpha-micro-ohms-per-ohm-celsius: > + description: | > + Linear approximation of the resistance versus temperature relationship > + between 0 and 100 degrees Celsius. > + > + Pure platinum has an alpha of 3925. Industry standards such as IEC60751 > + and ASTM E-1137 specify an alpha of 3850. Is there a max and min value? > + > + r-naught-ohms: > + description: | > + Resistance of the sensor at 0 degrees Celsius. > + Common values are 100 for PT100 and 1000 for PT1000. max or min? > + > +additionalProperties: false blank line here. > +required: > + - compatible > + - io-channels > + - excitation-current-microamp > + - alpha-micro-ohms-per-ohm-celsius > + - r-naught-ohms > + > +examples: > + - | > + pt1000_1: iio-rescale0 { > + compatible = "temperature-sense-rtd"; > + #io-channel-cells = <1>; > + io-channels = <&temp_adc1 0>; > + > + excitation-current-microamp = <1000>; > + alpha-micro-ohms-per-ohm-celsius = <3908>; > + r-naught-ohms = <1000>; > + }; > + > +... > diff --git a/MAINTAINERS b/MAINTAINERS > index d3ab0ccc34ab..a7279af85adb 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -8721,6 +8721,7 @@ L: linux-iio@vger.kernel.org > S: Maintained > F: Documentation/devicetree/bindings/iio/afe/current-sense-amplifier.yaml > F: Documentation/devicetree/bindings/iio/afe/current-sense-shunt.yaml > +F: Documentation/devicetree/bindings/iio/afe/temperature-sense-rtd.yaml > F: Documentation/devicetree/bindings/iio/afe/voltage-divider.yaml > F: drivers/iio/afe/iio-rescale.c > > -- > 2.30.1.489.g328c10930387