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References: <20211222034646.222189-1-liambeguin@gmail.com> <20211222034646.222189-12-liambeguin@gmail.com>
In-Reply-To: <20211222034646.222189-12-liambeguin@gmail.com>
From:   Andy Shevchenko <andy.shevchenko@gmail.com>
Date:   Wed, 22 Dec 2021 14:38:13 +0200
Message-ID: <CAHp75Ve4RuJLMdpdKe14nobuZHRNKA7tWt4yE82+noF5p+xxpw@mail.gmail.com>
Subject: Re: [PATCH v11 11/15] iio: test: add basic tests for the iio-rescale driver
To:     Liam Beguin <liambeguin@gmail.com>
Cc:     Peter Rosin <peda@axentia.se>, Jonathan Cameron <jic23@kernel.org>,
        Lars-Peter Clausen <lars@metafoo.de>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linux-iio <linux-iio@vger.kernel.org>,
        devicetree <devicetree@vger.kernel.org>,
        Rob Herring <robh+dt@kernel.org>
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On Wed, Dec 22, 2021 at 5:47 AM Liam Beguin <liambeguin@gmail.com> wrote:
>
> From: Liam Beguin <lvb@xiphos.com>
>
> The iio-rescale driver supports various combinations of scale types and
> offsets. These can often result in large integer multiplications. Make
> sure these calculations are done right by adding a set of kunit test
> cases that build on top of iio-test-format.

...

> +       int fract_mult = 100000000LL;

Perhaps also change to use the prefix?

...

> +       *nano = (s64)tmp * 10 * fract_mult + tmp2;

I'm also puzzled what the meaning of the 10 is here?

...

> +       err = 1000000 * abs(exp - real);

Prefix?

...

> +       err = div64_u64(err, abs(exp));
> +       return (int)err;

return div64_u64();

-- 
With Best Regards,
Andy Shevchenko