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=-20.4 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_AGENT_GIT,USER_IN_DEF_DKIM_WL 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 36334C4727F for ; Thu, 24 Sep 2020 21:54:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F1A8421D20 for ; Thu, 24 Sep 2020 21:54:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="FWvIVB4n" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726709AbgIXVy4 (ORCPT ); Thu, 24 Sep 2020 17:54:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41966 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726705AbgIXVyz (ORCPT ); Thu, 24 Sep 2020 17:54:55 -0400 Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 98F84C0613D6 for ; Thu, 24 Sep 2020 14:54:55 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id u35so650124ybd.13 for ; Thu, 24 Sep 2020 14:54:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:date:in-reply-to:message-id:mime-version:references:subject :from:to; bh=TuyfSxIkZi+P/JhBNIB6urUJLMN4tVR/8LkLgR5gW14=; b=FWvIVB4nFy3TjF5TUaGKfr+gr0IDuCj3iVXYiz3beykXZPAzbGXNgRRCPQB206Y1KQ WdZtttptVeUthPPTUhjCn1TS4PeYU2tViVkVdp3dP9LaFDi7T6qd8VsmnDZeQZWmODM1 9Znb9S+vKoQy59WNTM1nvYuWItx4WnHMy0G52VerG4CajSRNUvoGkGUJIxFRLBawOzAu uDnJ7UAuk0mW8VgMcKRk5EJZTQohl3aUyJtzunt+Y+/gBZhM3kCWCKsblFn0HCOlJulg 4JciRiKxwuf1siqUq3/Eu7De/jsoTXRVXgrx3AOhb83Xz/oUmnVtaT+IKXkIavPcAgjD vCfQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:in-reply-to:message-id:mime-version :references:subject:from:to; bh=TuyfSxIkZi+P/JhBNIB6urUJLMN4tVR/8LkLgR5gW14=; b=F2CHyKDPIRjN1qeGKELDaHz9FJ0VeL7+9qq3tpwymS51quX1MGnQppYilLwiB/e2NT q7CIRE5c/GbWU3ev3YKmI5n5Q8155ZWAasTZGus8U99sRndfPlBkq+qlGO0/lxNsfup3 osLnI3OoDNzGDeCJm9018OxLMVCV6KFNS86TLzSIVazNcIvQSDHFePqFajwcFtpcYV7p /tB/ooYXj7qajDAgtBjlFyxtO5jZWz6DZqx2QYy1BAUO/3jSZuKSuTbL6w+ZKrlNhr3W jl20loJBSinvIgr37lEhurqAwSrl7Cyn4oBYODTm6wlOKpbpyDe9cw8fGK9tBbpnTH3H sAaQ== X-Gm-Message-State: AOAM533W9fA94f+XheO1ftZ7IP+qmb2gyQdkiGnM14Qab85ST54wQj1Y h9g8NpgS85YBVO1ALeh4Sg3ktNvs1AM43g61 X-Google-Smtp-Source: ABdhPJzk4yQgT36MZ0fV0H+HiXWybvORRJARsR02oEoMKu0Ap8ErrcXpHPJ3T5bsC1iNb+dOpAdOjLETvfnRZ1cH Sender: "linchuyuan via sendgmr" X-Received: from chu-dev.c.googlers.com ([fda3:e722:ac3:10:24:72f4:c0a8:3cfb]) (user=linchuyuan job=sendgmr) by 2002:a25:e0d2:: with SMTP id x201mr1323962ybg.180.1600984494820; Thu, 24 Sep 2020 14:54:54 -0700 (PDT) Date: Thu, 24 Sep 2020 21:54:44 +0000 In-Reply-To: <20200924215444.2865885-1-linchuyuan@google.com> Message-Id: <20200924215444.2865885-3-linchuyuan@google.com> Mime-Version: 1.0 References: <20200924215444.2865885-1-linchuyuan@google.com> X-Mailer: git-send-email 2.28.0.681.g6f77f65b4e-goog Subject: [PATCH v3 2/2] hwmon: pmbus: max20730: adjust the vout reading given voltage divider From: Chu Lin To: linchuyuan@google.com, jdelvare@suse.com, linux@roeck-us.net, robh+dt@kernel.org, linux-hwmon@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, qiongwang@google.com, zhongqil@google.com, jasonling@google.com, belgaied@google.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-hwmon@vger.kernel.org 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 | 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) -- 2.28.0.681.g6f77f65b4e-goog