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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 27CC7C00140 for ; Thu, 18 Aug 2022 20:15:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345479AbiHRUPF (ORCPT ); Thu, 18 Aug 2022 16:15:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51148 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345914AbiHRUOn (ORCPT ); Thu, 18 Aug 2022 16:14:43 -0400 Received: from mail-pl1-x636.google.com (mail-pl1-x636.google.com [IPv6:2607:f8b0:4864:20::636]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 52D39CB5E7; Thu, 18 Aug 2022 13:14:02 -0700 (PDT) Received: by mail-pl1-x636.google.com with SMTP id jm11so2395933plb.13; Thu, 18 Aug 2022 13:14:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:sender:from:to:cc; bh=egYSJNbQxtbIjtuZxTLb7Op2z9efDIBz0CVG82pd35Q=; b=OrdgxQZHf0g36dqgz8oBTc9Pw5flV5lUnAKO+L/BXl1IbHMz6Y0SdtGaYvkVBINho4 lDQxJFuriCNhvRWKDJNhT68uzk2DPMhppFWOYNcSIqRtXgQ007eDkXLtc+jww6Lj5KLD bi5Hl0bUgFcwQCWbAGu7DenppWIMcGBnYco7S8QPnPoDXHha8aQzzDXNw1MH45MtU5YD h79Ex5qk3hBSkTCq5yMPSmY4oysetZiE+lOLmlZG0IiY73TIsd5bixD5Ch64z4MmscdV 7xJE0+dTV8j1ZGcn7S3l71FVgayPZcdCrd1NjyNiOIJhXeHyVtH+Ok8VxHPO6GsW1++T q1ig== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:sender:x-gm-message-state:from:to:cc; bh=egYSJNbQxtbIjtuZxTLb7Op2z9efDIBz0CVG82pd35Q=; b=RLE+omWKLqZU1kiF1oKN0jXPYrYf+X3C+PFVXDU5LIicpP6m5L+3c5vetN9Jxn28Ls dpQSw27C3gdcCn2NYTpmEgE1IubqgVW9hyx8SMFwY8LBM2yuu0QJv2wNF0FF3A0Q6eg/ FA3lCUAg4kDDaUQlB6yckvnqrtvBn7Xt6LLHj2ldH6tFZqVmYAETT9/xTb1v4WG/YoSv KnqzD9kStnlTJWWUDoVzcVreBCtot73sH2dPvjsAyndsGofDVFrbYPwf0iov9DsugTsQ j4BwwOPlC6sH5ZtilECeiPt4layNNxOO/r1lyxVN0Sq8ZOKZ0oJAsCxFB3AgstzCUO9Y dVqQ== X-Gm-Message-State: ACgBeo0VRBv4ln+k2cNfhOVOkNK9RovyIuMy82PARqvRdJXr1RxW2YLR gvq1OZ8mz3CeR9J3fDP4hvE= X-Google-Smtp-Source: AA6agR4k9h5ht6adNQ4cG6aZIayrOdx0qxU/jk7nZlcuvmViw6faXm9ppDtDbTHN6V4LU/YdyEvwDA== X-Received: by 2002:a17:90b:4653:b0:1f3:1ce3:2cb with SMTP id jw19-20020a17090b465300b001f31ce302cbmr10134904pjb.176.1660853641591; Thu, 18 Aug 2022 13:14:01 -0700 (PDT) Received: from server.roeck-us.net ([2600:1700:e321:62f0:329c:23ff:fee3:9d7c]) by smtp.gmail.com with ESMTPSA id n3-20020aa79843000000b0052dd7d0ad04sm2058779pfq.88.2022.08.18.13.14.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 18 Aug 2022 13:14:00 -0700 (PDT) Sender: Guenter Roeck Date: Thu, 18 Aug 2022 13:13:59 -0700 From: Guenter Roeck To: Eliav Farber Cc: jdelvare@suse.com, robh+dt@kernel.org, mark.rutland@arm.com, linux-hwmon@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, talel@amazon.com, hhhawa@amazon.com, jonnyc@amazon.com, hanochu@amazon.com, ronenk@amazon.com, itamark@amazon.com, shellykz@amazon.com, shorer@amazon.com, amitlavi@amazon.com, almogbs@amazon.com, dwmw@amazon.co.uk, rtanwar@maxlinear.com Subject: Re: [PATCH v2 11/16] hwmon: (mr75203) add protection for negative voltage value Message-ID: <20220818201359.GA3430651@roeck-us.net> References: <20220817054321.6519-1-farbere@amazon.com> <20220817054321.6519-12-farbere@amazon.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220817054321.6519-12-farbere@amazon.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 17, 2022 at 05:43:16AM +0000, Eliav Farber wrote: > This change makes sure the returned voltage vlaue is 0 or positive. > > Signed-off-by: Eliav Farber > --- > drivers/hwmon/mr75203.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/drivers/hwmon/mr75203.c b/drivers/hwmon/mr75203.c > index 24a00339cfd8..e3191f590167 100644 > --- a/drivers/hwmon/mr75203.c > +++ b/drivers/hwmon/mr75203.c > @@ -218,6 +218,13 @@ static int pvt_read_in(struct device *dev, u32 attr, int channel, long *val) > return ret; > > n &= SAMPLE_DATA_MSK; > + > + /* Voltage can't be negative */ Who says, and what does that mean ? Under which conditions would the value be negative, and why would that be a problem / bug ? After all, negative voltages do exist. Guenter > + if (PVT_N_CONST * n < PVT_R_CONST) { > + *val = 0; > + return 0; > + } > + > /* Convert the N bitstream count into voltage */ > *val = pvt->vd[channel].pre_scaler; > *val *= (PVT_N_CONST * n - PVT_R_CONST);