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=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 1956EC4363D for ; Thu, 24 Sep 2020 21:54:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CB93D21D20 for ; Thu, 24 Sep 2020 21:54:58 +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 S1726723AbgIXVy5 (ORCPT ); Thu, 24 Sep 2020 17:54:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41964 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726606AbgIXVyz (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 9559CC0613D5 for ; Thu, 24 Sep 2020 14:54:55 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id n13so664696ybk.9 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=BcQVnLoJzGUiWnj8TkarESVsjs8gJi4SFJLf7yuF8yvJqFJfa4NsgnhIqqFGvHyKZD nlG3oLd8Q5j/WXC8+wAE7ysdR4xAyP7AaEuhiyQCFGXlWQrxOitHlaDh20QvZWQzmB6R xOYM+57tu7HNTwvinLK+aFEMt+qfbUvyyH/SL2oPQzbx1qa+sYg0HB78l+T6/7UncYTp yBaUkX9namPSUaet25rc/aoaZTkcgwMUqUCzRyVWJNz8lK/BMKqPfKdfdZ4KtIkZ+KQo BSAE7GM7MWTxRoVC7N1ReG2Mjdd3XEpoJFplsmBV1aZKFnYIKEPiFONLkjmCkcAND+0s OXiw== X-Gm-Message-State: AOAM533rLJVz3WSmOznXuJOxG6nA+uc+lxz8oQ+aahtoQDXOQ8KEo0F4 4lHG9uzktRzHTDENBi1Yk4f2E8AlKL8v9rus 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-kernel@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