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=-17.4 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_IN_DEF_DKIM_WL 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 5B146C43461 for ; Thu, 10 Sep 2020 17:21:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EE5CA2064B for ; Thu, 10 Sep 2020 17:21:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="tQcXN1GA" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726676AbgIJRVY (ORCPT ); Thu, 10 Sep 2020 13:21:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54758 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726932AbgIJRU3 (ORCPT ); Thu, 10 Sep 2020 13:20:29 -0400 Received: from mail-ej1-x642.google.com (mail-ej1-x642.google.com [IPv6:2a00:1450:4864:20::642]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B62A3C061796 for ; Thu, 10 Sep 2020 10:20:27 -0700 (PDT) Received: by mail-ej1-x642.google.com with SMTP id i22so9872910eja.5 for ; Thu, 10 Sep 2020 10:20:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to; bh=HJ4WCgkKVpSJwvVsPhFStCc8bgYAbRqt32AnN8mYRds=; b=tQcXN1GAvYhoCJVfJUxAp9ZFrHI6GU2nv68Zoqa+AvUsab3E/b8REHZJiVT2YHw90u bi6E5/BAHpPRaNok1/vOMMDcMutDeM+pRZeN+TmpRpd3278L6ZAsd65qWtBFL6AUAVHb aV7WDk2fr493Oe0B1CyOTzkL27cFLnZWDj/1zYZzqQKlYNVN3thX0Jk9gg/O4fjWtepo HVeM+wYeuf/astvWHsCus2wuxU1KaUy4sFcK0uZxNZJYswLnRf1IpK9OhayKSiqc9G+G Vxcb7rKADkCl1bHCpxz1nhfP1++fgKLftsWsMnFudTWkZgyVPB1jhqB2shcUDp8Hr1mZ cQGA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to; bh=HJ4WCgkKVpSJwvVsPhFStCc8bgYAbRqt32AnN8mYRds=; b=bkmPTG24QiRv2N398PIvTOPFtSCmFnoq/VM4+NLaL7YquH+fZfsAUCVP53jXxpEt3q JfhgtAo3P+9Ease3allOr1c4BqNCwNr8vEfetb892GScLAIMYj7HQmNB6FlCv9RbAYjn OxmL/NJW0osY2mLHvS8B9bu6JXgYd+GfraC+A8oJco8tkCDH1GkfMSxUyE4go0R/Cje8 GUFXJ2mEW3umaeG3g4U+OiCArXeOUkH7T2QDotmozvw1DtSBRunJ0Xp/W0VXS/UngJRV TeZCHYgtaw9nAdDPCfszvQD6No4bxSaI1oRPJqGAdm02X8N3v+jFJQ4Svn/CJvwj5iqX NYoQ== X-Gm-Message-State: AOAM533srw0gGY57doLLlTY12y/lNmM31jLT4epxs/jMMTG6W7ISmMRK maeySbRZk4fNGmsY2jdchrt7VCUXjqzwQBgBwvsU0A== X-Google-Smtp-Source: ABdhPJyb+x7vObwo6KSEusHlPUEiXe9p2AnJQuZowHtorgy1L4c4db1C5Htxw0Ap5DN/mK2cmW9LUot6bs31yivl4ZI= X-Received: by 2002:a17:906:7489:: with SMTP id e9mr9732119ejl.154.1599758426140; Thu, 10 Sep 2020 10:20:26 -0700 (PDT) MIME-Version: 1.0 References: <20200910170910.1990578-1-linchuyuan@google.com> In-Reply-To: <20200910170910.1990578-1-linchuyuan@google.com> From: Chu Lin Date: Thu, 10 Sep 2020 10:20:15 -0700 Message-ID: Subject: Re: [PATCH] hwmon: pmbus: max20730: adjust the vout reading given voltage divider To: Chu Lin , jdelvare@suse.com, Guenter Roeck , linux-kernel@vger.kernel.org, linux-hwmon@vger.kernel.org, Qiong Wang , Zhongqi Li , Jason Ling , Kais Belgaied Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The same patch got sent twice. Please, discard this one. Thanks, Chu On Thu, Sep 10, 2020 at 10:09 AM 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 > --- > drivers/hwmon/pmbus/max20730.c | 16 ++++++++++++++++ > 1 file changed, 16 insertions(+) > > diff --git a/drivers/hwmon/pmbus/max20730.c b/drivers/hwmon/pmbus/max20730.c > index c0bb05487e0e..4b56810fa894 100644 > --- a/drivers/hwmon/pmbus/max20730.c > +++ b/drivers/hwmon/pmbus/max20730.c > @@ -29,6 +29,7 @@ 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) > @@ -111,6 +112,12 @@ 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 (data->vout_voltage_divider[0] && data->vout_voltage_divider[1]) > + ret = DIV_ROUND_CLOSEST(ret * data->vout_voltage_divider[1], > + data->vout_voltage_divider[0]); > + break; > default: > ret = -ENODATA; > break; > @@ -329,6 +336,15 @@ 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) > -- > 2.28.0.526.ge36021eeef-goog >