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=-12.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 C7DEEC43216 for ; Sun, 29 Aug 2021 02:33:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A8AB760E08 for ; Sun, 29 Aug 2021 02:33:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232591AbhH2CeW (ORCPT ); Sat, 28 Aug 2021 22:34:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47774 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230334AbhH2CeV (ORCPT ); Sat, 28 Aug 2021 22:34:21 -0400 Received: from mail-qt1-x830.google.com (mail-qt1-x830.google.com [IPv6:2607:f8b0:4864:20::830]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 48E5BC061756; Sat, 28 Aug 2021 19:33:30 -0700 (PDT) Received: by mail-qt1-x830.google.com with SMTP id b4so3031343qtx.0; Sat, 28 Aug 2021 19:33:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=qyyw88XUoVSPXUSIJPLbWlKHnsd2Pz+wgMDoo6t0tsE=; b=oSFf4Anr9+dpcNVMfxqVPktR38wBMnQJwfdEznhZStCq9viDUD7g7IYsaYxm6TjC76 aPHuKHbbNWgPzkY0TcyLEKcimKxL2sSIwzuLo3cV4sC7IRRO2VeqycZeKVbZFqFDKpjs MaY0U5YJWeANpI+13egdVlHLV8H2QeJp6zzaO3LIuuFDt4/mpClZSScih0I17iv05hIW WjS0IjAQi19ahctWIqnoBY9XQFpBJkbO69Diz4STJmN5hM4DUF735gj0hoV0LAemEMsL y1KfRjEm8slBsyWLc3E18ZxZ2pabJxDrurlLlWw/KkhvN0Z4yGP6zf47eRrouAFwKqqI +yMQ== 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=qyyw88XUoVSPXUSIJPLbWlKHnsd2Pz+wgMDoo6t0tsE=; b=lrmxn86hdHnwq0RQsx9JNwsui1R5aBbe0PkXUvfD7kyT5F/dMK84tvonbaQ5sKiWdJ 5o3fnHWU7P7MhpSEDEvg+nG9I1Ntlb0OFvgEG/4kVyolOZ23lO5Q1uFDuys4gSjVNdx4 gXX9mnkQePobol7uBJ215OHUn6gmBrxnla4FD/1MZJLXNQKAc7N1W+q4THFEx36PLqSt +mCwO76jqTW1/C2lrXuxpuvM0ERR/ZoHMM3xd0jXwtSjerm32THtFhaprM/1Z6BicHez 7exEcDzdWR7gd61RZV7f7iVik8FaO7eIplTUIWienxJsQli7bsMnc4G/OKcY2i6PSy1B CpzQ== X-Gm-Message-State: AOAM530Rd5FQw39lfzaHfn7DGr9K1d5+Xx4+PB37HLwSTEGzz9+fKEtN eMTWUzPYl5zetmRGVuFreGs= X-Google-Smtp-Source: ABdhPJwuZe3JqEyYnyuJdrDAGGBvo9ZtETvYrKFyNsQaK00skNSb/e3vszPkSTcG741SQQs5f8w8MQ== X-Received: by 2002:ac8:570e:: with SMTP id 14mr15041507qtw.302.1630204408075; Sat, 28 Aug 2021 19:33:28 -0700 (PDT) Received: from shaak (198-48-202-89.cpe.pppoe.ca. [198.48.202.89]) by smtp.gmail.com with ESMTPSA id d13sm2955406qtm.32.2021.08.28.19.33.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 28 Aug 2021 19:33:27 -0700 (PDT) Date: Sat, 28 Aug 2021 22:33:25 -0400 From: Liam Beguin To: Peter Rosin Cc: jic23@kernel.org, lars@metafoo.de, linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org, devicetree@vger.kernel.org, robh+dt@kernel.org Subject: Re: [PATCH v8 12/14] iio: afe: rescale: add temperature transducers Message-ID: References: <20210820191714.69898-1-liambeguin@gmail.com> <20210820191714.69898-13-liambeguin@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Thu, Aug 26, 2021 at 10:56:11AM +0200, Peter Rosin wrote: > On 2021-08-20 21:17, Liam Beguin wrote: > > From: Liam Beguin > > > > A temperature transducer is a device that converts a thermal quantity > > into any other physical quantity. This patch add support for temperature > > to voltage (like the LTC2997) and temperature to current (like the > > AD590) linear transducers. > > In both cases these are assumed to be connected to a voltage ADC. > > > > Signed-off-by: Liam Beguin > > --- > > drivers/iio/afe/iio-rescale.c | 33 +++++++++++++++++++++++++++++++++ > > 1 file changed, 33 insertions(+) > > > > diff --git a/drivers/iio/afe/iio-rescale.c b/drivers/iio/afe/iio-rescale.c > > index 8cdcb6ffb563..12de44058bea 100644 > > --- a/drivers/iio/afe/iio-rescale.c > > +++ b/drivers/iio/afe/iio-rescale.c > > @@ -427,11 +427,38 @@ static int rescale_temp_sense_rtd_props(struct device *dev, > > return 0; > > } > > > > +static int rescale_temp_transducer_props(struct device *dev, > > + struct rescale *rescale) > > +{ > > + s32 offset = 0; > > + s32 sense = 1; > > + s32 alpha; > > + s64 tmp; > > + int ret; > > + > > + device_property_read_u32(dev, "sense-offset-millicelsius", &offset); > > + device_property_read_u32(dev, "sense-resistor-ohms", &sense); > > + ret = device_property_read_u32(dev, "alpha-ppm-per-celsius", &alpha); > > + if (ret) { > > + dev_err(dev, "failed to read alpha-ppm-per-celsius: %d\n", ret); > > + return ret; > > + } > > + > > + rescale->numerator = 1000000; > > + rescale->denominator = alpha * sense; > > + > > + tmp = (s64)offset * (s64)alpha * (s64)sense; > > + rescale->offset = div_s64(tmp, (s32)1000000); > > Error: Too many casts :-) Oof! You're right, that doesn't look too good... I guess I haven't looked at this part of the series for a few revisions, my bad. > > I think it would make sense to lose tmp, and just spell it out in one > statement? > > rescale->offset = div_s64((s64)offset * rescale->denominator, > rescale->numerator); > > Because you are prepping the offset so that it will survive a later rescaler > multiplication, and all the "random" multiplications and divisions don't > make that very clear. > Yeah, I agree! The way I had it spelled out wasn't much more readable. I'll use your suggestion instead. Thanks, Liam > Cheers, > Peter > > > + > > + return 0; > > +} > > + > > enum rescale_variant { > > CURRENT_SENSE_AMPLIFIER, > > CURRENT_SENSE_SHUNT, > > VOLTAGE_DIVIDER, > > TEMP_SENSE_RTD, > > + TEMP_TRANSDUCER, > > }; > > > > static const struct rescale_cfg rescale_cfg[] = { > > @@ -451,6 +478,10 @@ static const struct rescale_cfg rescale_cfg[] = { > > .type = IIO_TEMP, > > .props = rescale_temp_sense_rtd_props, > > }, > > + [TEMP_TRANSDUCER] = { > > + .type = IIO_TEMP, > > + .props = rescale_temp_transducer_props, > > + }, > > }; > > > > static const struct of_device_id rescale_match[] = { > > @@ -462,6 +493,8 @@ static const struct of_device_id rescale_match[] = { > > .data = &rescale_cfg[VOLTAGE_DIVIDER], }, > > { .compatible = "temperature-sense-rtd", > > .data = &rescale_cfg[TEMP_SENSE_RTD], }, > > + { .compatible = "temperature-transducer", > > + .data = &rescale_cfg[TEMP_TRANSDUCER], }, > > { /* sentinel */ } > > }; > > MODULE_DEVICE_TABLE(of, rescale_match); > >