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 0DD7CC07E9C for ; Mon, 12 Jul 2021 14:57:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D4F5E611B0 for ; Mon, 12 Jul 2021 14:57:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235116AbhGLPAm (ORCPT ); Mon, 12 Jul 2021 11:00:42 -0400 Received: from mail-il1-f170.google.com ([209.85.166.170]:46031 "EHLO mail-il1-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233784AbhGLPAm (ORCPT ); Mon, 12 Jul 2021 11:00:42 -0400 Received: by mail-il1-f170.google.com with SMTP id b6so10235193iln.12; Mon, 12 Jul 2021 07:57:52 -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=WVxRJEnC1GdQvhchP0t++AaKpXBj2Uta5gjvaVcQ8l0=; b=VWBFVgKqV7SrK3ZfhRciuI8UMbvjzmIEhF7dhUSiVDNI4a1o/wsovYG+/vVUZzwX/o U+9ZDhvMyDnHX3i5B+cZLgPKPlpJ6CQE6i8z5bQGLYin45zrd7ZzpJXqn7c/lMfAWl0f EiNnvj/9LRkwp8o1UDddzgqtglQiCmUgpyNM1taaJs7lGZzU1I0KBvz+fm85ebHX+dPS MX1/CrAjvtb9xtyaIlYgmaJav3AAkGJxzhGIlbE5TD1jlR8ZMUB5i1gvcTR933niVrYh /dak3CF/48UgxsYJz08lMFHuJmVLme8/iU94zPdM+XbVoEzYal9+I8D5A7iIEkRM84PR GJNg== X-Gm-Message-State: AOAM531yQM4yQ7s+KZTVI2lTIA766r6GO7zmEcPuQVO8NlWIMsWdxee+ 3eoGdjALJsBOcQmV9PB7921HLkE/OQ== X-Google-Smtp-Source: ABdhPJwTWG2XzaqVCYwc/OPCbgG1nfl/Hw3uzMQNldk0we+DPR76FQ6tAycpo/NEcC/HzOrTOHZPfA== X-Received: by 2002:a05:6e02:1a24:: with SMTP id g4mr4417167ile.260.1626101872563; Mon, 12 Jul 2021 07:57:52 -0700 (PDT) Received: from robh.at.kernel.org ([64.188.179.248]) by smtp.gmail.com with ESMTPSA id 15sm8238197ilt.66.2021.07.12.07.57.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 12 Jul 2021 07:57:51 -0700 (PDT) Received: (nullmailer pid 1919318 invoked by uid 1000); Mon, 12 Jul 2021 14:57:49 -0000 Date: Mon, 12 Jul 2021 08:57:49 -0600 From: Rob Herring To: Linus Walleij Cc: Jean Delvare , Guenter Roeck , linux-hwmon@vger.kernel.org, Javier Martinez Canillas , Johannes Pointner , Peter Rosin , Jonathan Cameron , devicetree@vger.kernel.org Subject: Re: [PATCH v2] dt-bindings: hwmon: Convert NTC thermistor to YAML Message-ID: <20210712145749.GA1911897@robh.at.kernel.org> References: <20210703173456.4002549-1-linus.walleij@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210703173456.4002549-1-linus.walleij@linaro.org> Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Sat, Jul 03, 2021 at 07:34:56PM +0200, Linus Walleij wrote: > This converts the NTC thermistor DT bindings to YAML. Some care had to > be taken since I had to add some illustrations to make the connection > layouts graspable. > > Cc: Javier Martinez Canillas > Cc: Johannes Pointner > Cc: Peter Rosin > Cc: Jonathan Cameron > Cc: devicetree@vger.kernel.org > Signed-off-by: Linus Walleij > --- > ChangeLog v1->v2: > - Realize I need to CC devicetree@vger.kernel.org on this. > - Fix Javier's mail address. > - Drop Naveen's mail (bouncing) > --- > .../bindings/hwmon/ntc-thermistor.yaml | 142 ++++++++++++++++++ > .../bindings/hwmon/ntc_thermistor.txt | 44 ------ > 2 files changed, 142 insertions(+), 44 deletions(-) > create mode 100644 Documentation/devicetree/bindings/hwmon/ntc-thermistor.yaml > delete mode 100644 Documentation/devicetree/bindings/hwmon/ntc_thermistor.txt > > diff --git a/Documentation/devicetree/bindings/hwmon/ntc-thermistor.yaml b/Documentation/devicetree/bindings/hwmon/ntc-thermistor.yaml > new file mode 100644 > index 000000000000..87589da631c9 > --- /dev/null > +++ b/Documentation/devicetree/bindings/hwmon/ntc-thermistor.yaml > @@ -0,0 +1,142 @@ > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause) > +--- > +$id: http://devicetree.org/schemas/hwmon/ntc-thermistor.yaml# > +$schema: http://devicetree.org/meta-schemas/core.yaml# > + > +title: NTC thermistor temperature sensors > + > +maintainers: > + - Naveen Krishna Chatradhi > + - Linus Walleij > + > +description: | > + Thermistors with negative temperature coefficient (NTC) are resistors that > + vary in resistance in an often non-linear way in relation to temperature. > + The negative temperature coefficient means that the resistance decreases > + as the temperature rises. Since the relationship between resistance and > + temperature is non-linear, software drivers most often need to use a look > + up table and interpolation to get from resistance to temperature. > + > + When used in practice, a thermistor is often connected between ground, a > + pull-up resistor or/and a pull-down resistor and a fixed voltage like this: > + > + + e.g. 5V = pull-up voltage (puv) > + | > + +-+ > + | | > + | | Pull-up resistor > + | | (puo) > + +-+ > + |-------------------------o > + +-+ | ^ > + | |/ | > + | / | > + |/| Thermistor | Measured voltage (mv) > + / | | "connected ground" > + /| | | > + +-+ | > + |-------------------------o > + +-+ ^ > + | | | > + | | Pull-down resistor | Measured voltage (mv) > + | | (pdo) | "connected positive" > + +-+ | > + | | > + | v > + + GND GND > + > + The arrangements of where we measure the voltage over the thermistor are > + called "connected ground" and "connected positive" and shall be understood as > + the cases when either pull-up or pull-down resistance is zero. > + > + If the pull-up resistance is 0 one end of the thermistor is connected to the > + positive voltage and we get the thermistor on top of a pull-down resistor > + and we take the measure between the thermistor and the pull-down resistor. > + > + Conversely if the pull-down resistance is zero, one end of the thermistor is > + connected to ground and we get the thermistor under the pull-up resistor > + and we take the measure between the pull-up resistor and the thermistor. > + > + We can use both pull-up and pull-down resistors at the same time, and then > + the figure illustrates where the voltage will be measured for the "connected > + ground" and "connected positive" cases. > + > +properties: > + $nodename: > + pattern: "^thermistor(.*)?$" > + > + compatible: > + oneOf: > + - const: epcos,b57330v2103 > + - const: epcos,b57891s0103 > + - const: murata,ncp15wb473 > + - const: murata,ncp18wb473 > + - const: murata,ncp21wb473 > + - const: murata,ncp03wb473 > + - const: murata,ncp15wl333 > + - const: murata,ncp03wf104 > + - const: murata,ncp15xh103 All these can be 1 enum. > + # Deprecated "ntp," compatible strings > + - const: ntc,ncp15wb473 > + deprecated: true > + - const: ntc,ncp18wb473 > + deprecated: true > + - const: ntc,ncp21wb473 > + deprecated: true > + - const: ntc,ncp03wb473 > + deprecated: true > + - const: ntc,ncp15wl333 > + deprecated: true And these too. > + > + # See /schemas/thermal/thermal-sensor.yaml for details Drop. (I hope to generate documentation from the schema and automagically create references/links.) > + "#thermal-sensor-cells": > + description: Thermal sensor cells if used for thermal sensoring. > + const: 0 > + > + pullup-uv: > + $ref: /schemas/types.yaml#/definitions/uint32 > + description: Pull-up voltage in micro volts. Must always be specified. > + > + pullup-ohm: > + $ref: /schemas/types.yaml#/definitions/uint32 > + description: Pull-up resistance in ohms. Must always be specified, even > + if zero. > + > + pulldown-ohm: > + $ref: /schemas/types.yaml#/definitions/uint32 > + description: Pull-down resistance in ohms. Must always be specified, even > + if zero. > + > + connected-positive: > + $ref: /schemas/types.yaml#/definitions/flag > + description: Indicates how the thermistor is connected in series with > + a pull-up and/or a pull-down resistor. See the description above for > + an illustration. If this flag is NOT specified, the thermistor is assumed > + to be connected-ground, which usually means a pull-down resistance of > + zero but complex arrangements are possible. > + > + # See /schemas/iio/adc/adc.yaml > + io-channels: > + maxItems: 1 > + description: IIO ADC channel to read the voltage over the resistor. Must > + always be specified. > + > +required: > + - compatible > + - pullup-uv > + - pullup-ohm > + - pulldown-ohm > + - io-channels > + > +additionalProperties: false > + > +examples: > + - | > + thermistor0 { > + compatible = "murata,ncp18wb473"; > + io-channels = <&gpadc 0x06>; > + pullup-uv = <1800000>; > + pullup-ohm = <220000>; > + pulldown-ohm = <0>; > + #thermal-sensor-cells = <0>; > + };