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References: <20210624224909.6350-1-pali@kernel.org> <20210717123829.5201-1-pali@kernel.org>
 <20210717123829.5201-2-pali@kernel.org>
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From:   Andy Shevchenko <andy.shevchenko@gmail.com>
Date:   Mon, 19 Jul 2021 15:47:07 +0300
Message-ID: <CAHp75VeCC3cYu3RZPxuRN4iaM+vxp2rX+E4z+ZxzRGM8oHaMkw@mail.gmail.com>
Subject: Re: [PATCH v3 1/5] math64: New DIV_U64_ROUND_CLOSEST helper
To:     =?UTF-8?Q?Pali_Roh=C3=A1r?= <pali@kernel.org>
Cc:     Michael Turquette <mturquette@baylibre.com>,
        Stephen Boyd <sboyd@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Andrew Lunn <andrew@lunn.ch>,
        Gregory Clement <gregory.clement@bootlin.com>,
        Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>,
        Vladimir Vid <vladimir.vid@sartura.hr>,
        =?UTF-8?B?TWFyZWsgQmVow7pu?= <kabel@kernel.org>,
        Geert Uytterhoeven <geert@linux-m68k.org>,
        linux-clk@vger.kernel.org, linux-serial@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org
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On Sat, Jul 17, 2021 at 3:39 PM Pali Roh=C3=A1r <pali@kernel.org> wrote:
>
> Provide DIV_U64_ROUND_CLOSEST helper which uses div_u64 to perform
> division rounded to the closest integer using unsigned 64bit
> dividend and unsigned 32bit divisor.

...

> +/*
> + * DIV_U64_ROUND_CLOSEST - unsigned 64bit divide with 32bit divisor roun=
ded to nearest integer

> + * @dividend: unsigned 64bit dividend

Here you insist users to provide a u64 (or compatible) type.

> + * @divisor: unsigned 32bit divisor
> + *
> + * Divide unsigned 64bit dividend by unsigned 32bit divisor
> + * and round to closest integer.
> + *
> + * Return: dividend / divisor rounded to nearest integer
> + */
> +#define DIV_U64_ROUND_CLOSEST(dividend, divisor)       \

> +       ({ u32 _tmp =3D (divisor); div_u64((u64)(dividend) + _tmp / 2, _t=
mp); })

Here is the casting to u64. Why? (Yes, I have read v1 discussion and I
just want to continue it here).

--=20
With Best Regards,
Andy Shevchenko