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=-11.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 BDD0DC4363D for ; Tue, 6 Oct 2020 21:55:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5139C2083B for ; Tue, 6 Oct 2020 21:55:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="nnOYOYnI" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726970AbgJFVzz (ORCPT ); Tue, 6 Oct 2020 17:55:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48136 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726759AbgJFVzy (ORCPT ); Tue, 6 Oct 2020 17:55:54 -0400 Received: from mail-oi1-x243.google.com (mail-oi1-x243.google.com [IPv6:2607:f8b0:4864:20::243]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A8D01C061755; Tue, 6 Oct 2020 14:55:54 -0700 (PDT) Received: by mail-oi1-x243.google.com with SMTP id z26so185549oih.12; Tue, 06 Oct 2020 14:55:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=qPX3xlYEkCVFEJ7SQA+ZBYnQiRoEfDKRNohYw4I7fUc=; b=nnOYOYnIuRdYoA8hDimnqCrsNcKdvCXrkoRiWW/B7tQwk20bxxSYi8CIywV8kgWM3r H71C2MO6lViyaBnpMRpLMGXBmuemoZoZ++dw2hBV/ZwFmEmM3t43sFbrpzgyOnjrToRS oMf0aJtU4RhuMQHfiibb/emlUkl74rEOpRqP/t427ooFu6JarODJXmlcXJDpCVbEbJ27 9Q3xFwcT2y3lOEZIH9DecM3c3D69Mh6YxylNCGggDdIp46ts96hVouNJy/HdPUYyslXd S/4rHEbYPSFkBWUbcCC9uCytjcsN9dALkNRldcB+H44acC5KCIR6aKhysplVKQNasPMC aJlQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to:user-agent; bh=qPX3xlYEkCVFEJ7SQA+ZBYnQiRoEfDKRNohYw4I7fUc=; b=ZtmptKxXVujEK6XZHU6WFj4GsQszctzrI555IosKFolJ4vw2cwh3NxxCkaLEnKT+x7 hpfp7PucMG3bfwHcz7kaUpdhr/f0pugwMPMsp5ULytvIUguRxD/9k0oU/KzFeO8i/k2G ggUmvLimGhGfORTIO2Mg2VO4DCJJLqLEcFZ45jATrN2K8iu9RAxbPDCVzbi4RRWQZoaE /s9PiNZDG1SlNqwttGCLkpLDQ1lkdZZ9fWXqvUOxodk26s6Ct0PxdNDs6a3O5ODcDjiw wBP9pkevmcyW6AVCRPJPTc3rqPNkWSuIog0bkQWfnP2a9n22R+0DENca1keFvQS4Ubug zy5w== X-Gm-Message-State: AOAM530Z6WGB+eCsdHf4E5hmh3VsC4OO3W5KmeRySa//9iO+u4e6htWC wzHJ/f62oyQ/DKpAv8Vu9qCl7qwWLwU= X-Google-Smtp-Source: ABdhPJyVFAc4xVraTI1NeRjHU6Aam9kZS7ykCm1oo9V5W9/I8sFXbAOds88PRaRe8n0OTFg28OErtg== X-Received: by 2002:aca:b488:: with SMTP id d130mr231029oif.136.1602021354120; Tue, 06 Oct 2020 14:55:54 -0700 (PDT) Received: from localhost ([2600:1700:e321:62f0:329c:23ff:fee3:9d7c]) by smtp.gmail.com with ESMTPSA id d9sm44174oig.56.2020.10.06.14.55.53 (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Tue, 06 Oct 2020 14:55:53 -0700 (PDT) Sender: Guenter Roeck Date: Tue, 6 Oct 2020 14:55:52 -0700 From: Guenter Roeck To: Chu Lin Cc: jdelvare@suse.com, robh+dt@kernel.org, linux-hwmon@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v4 2/2] hwmon: pmbus: max20730: adjust the vout reading given voltage divider Message-ID: <20201006215552.GA96934@roeck-us.net> References: <20201004031445.2321090-1-linchuyuan@google.com> <20201004031445.2321090-3-linchuyuan@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201004031445.2321090-3-linchuyuan@google.com> User-Agent: Mutt/1.9.4 (2018-02-28) Precedence: bulk List-ID: X-Mailing-List: linux-hwmon@vger.kernel.org On Sun, Oct 04, 2020 at 03:14:45AM +0000, Chu Lin wrote: > Problem: > We use voltage dividers so that the voltage presented at the voltage > sense pins is confusing. We might need to convert these readings to more > meaningful readings given the voltage divider. > > Solution: > Read the voltage divider resistance from dts and convert the voltage > reading to a more meaningful reading. > > Testing: > max20730 with voltage divider > > Signed-off-by: Chu Lin > Reviewed-by: Guenter Roeck Applied to hwmon-next. > --- > ChangeLog v1 -> v2 > hwmon: pmbus: max20730: > - Don't do anything to the ret if an error is returned from pmbus_read_word > - avoid overflow when doing multiplication > > ChangeLog v2 -> v3 > dt-bindings: hwmon: max20730: > - Provide the binding documentation in yaml format > hwmon: pmbus: max20730: > - No change > > ChangeLog v3 -> v4 > dt-bindings: hwmon: max20730: > - Fix highefficiency to high efficiency in description > - Fix presents to present in vout-voltage-divider > - Add additionalProperties: false > hwmon: pmbus: max20730: > - No change > > drivers/hwmon/pmbus/max20730.c | 18 ++++++++++++++++++ > 1 file changed, 18 insertions(+) > > diff --git a/drivers/hwmon/pmbus/max20730.c b/drivers/hwmon/pmbus/max20730.c > index a151a2b588a5..fbf2f1e6c969 100644 > --- a/drivers/hwmon/pmbus/max20730.c > +++ b/drivers/hwmon/pmbus/max20730.c > @@ -31,6 +31,7 @@ struct max20730_data { > struct pmbus_driver_info info; > struct mutex lock; /* Used to protect against parallel writes */ > u16 mfr_devset1; > + u32 vout_voltage_divider[2]; > }; > > #define to_max20730_data(x) container_of(x, struct max20730_data, info) > @@ -114,6 +115,14 @@ static int max20730_read_word_data(struct i2c_client *client, int page, > max_c = max_current[data->id][(data->mfr_devset1 >> 5) & 0x3]; > ret = val_to_direct(max_c, PSC_CURRENT_OUT, info); > break; > + case PMBUS_READ_VOUT: > + ret = pmbus_read_word_data(client, page, phase, reg); > + if (ret > 0 && data->vout_voltage_divider[0] && data->vout_voltage_divider[1]) { > + u64 temp = DIV_ROUND_CLOSEST_ULL((u64)ret * data->vout_voltage_divider[1], > + data->vout_voltage_divider[0]); > + ret = clamp_val(temp, 0, 0xffff); > + } > + break; > default: > ret = -ENODATA; > break; > @@ -364,6 +373,15 @@ static int max20730_probe(struct i2c_client *client, > data->id = chip_id; > mutex_init(&data->lock); > memcpy(&data->info, &max20730_info[chip_id], sizeof(data->info)); > + if (of_property_read_u32_array(client->dev.of_node, "vout-voltage-divider", > + data->vout_voltage_divider, > + ARRAY_SIZE(data->vout_voltage_divider)) != 0) > + memset(data->vout_voltage_divider, 0, sizeof(data->vout_voltage_divider)); > + if (data->vout_voltage_divider[1] < data->vout_voltage_divider[0]) { > + dev_err(dev, > + "The total resistance of voltage divider is less than output resistance\n"); > + return -ENODEV; > + } > > ret = i2c_smbus_read_word_data(client, MAX20730_MFR_DEVSET1); > if (ret < 0)