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Subject: Re: [PATCH v2 2/2] iio: potentiometer: Add driver support for AD5110
To:     Andy Shevchenko <andy.shevchenko@gmail.com>,
        Mugilraj Dhavachelvan <dmugil2000@gmail.com>
Cc:     "Bogdan, Dragos" <Dragos.Bogdan@analog.com>,
        Darius <Darius.Berghe@analog.com>,
        Rob Herring <robh+dt@kernel.org>,
        Jonathan Cameron <jic23@kernel.org>,
        Michael Hennerich <Michael.Hennerich@analog.com>,
        Guenter Roeck <linux@roeck-us.net>,
        Chris Packham <chris.packham@alliedtelesis.co.nz>,
        Slawomir Stepien <sst@poczta.fm>,
        Krzysztof Kozlowski <krzk@kernel.org>,
        Alexandre Belloni <alexandre.belloni@bootlin.com>,
        Alexandru Ardelean <alexandru.ardelean@analog.com>,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-iio@vger.kernel.org
References: <20210809075745.160042-1-dmugil2000@gmail.com>
 <20210809075745.160042-3-dmugil2000@gmail.com>
 <CAHp75Ve=D1d5wFZgNseP=wGpteEkZHnmAi7j9ykKC+u_NrR5xw@mail.gmail.com>
From:   Lars-Peter Clausen <lars@metafoo.de>
Message-ID: <013bcb79-c496-44d8-2e93-57eb57834ee0@metafoo.de>
Date:   Wed, 11 Aug 2021 10:15:09 +0200
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On 8/10/21 2:49 PM, Andy Shevchenko wrote:
>
>> +       data->tol = data->cfg->kohms * (val & GENMASK(6, 0)) * 10 / 8;
>> +       if (!(val & BIT(7)))
>> +               data->tol *= -1;
> Shouldn't you simple use corresponding sign_extend*()?
The data is encoded a sign-magnitude. sign_extend() works for two's 
complement numbers.