linux-kernel - Re: [PATCH v2 2/2] spi: add SPI controller driver for UniPhier SoC

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Message-ID: <CAHp75VdrpOkonozNRUCzchsNHbgV=djecVDr0-fRiYAa4iDE0A@mail.gmail.com>
Date:   Mon, 30 Jul 2018 11:39:07 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Keiji Hayashibara <hayashibara.keiji@...ionext.com>
Cc:     Trent Piepho <tpiepho@...inj.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Rob Herring <robh+dt@...nel.org>,
        devicetree <devicetree@...r.kernel.org>,
        Masami Hiramatsu <masami.hiramatsu@...aro.org>,
        Hayashi, Kunihiko/林 邦彦 
        <hayashi.kunihiko@...ionext.com>, Mark Brown <broonie@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        linux-spi <linux-spi@...r.kernel.org>,
        Yamada, Masahiro/山田 真弘 
        <yamada.masahiro@...ionext.com>,
        linux-arm Mailing List <linux-arm-kernel@...ts.infradead.org>,
        Jassi Brar <jaswinder.singh@...aro.org>
Subject: Re: [PATCH v2 2/2] spi: add SPI controller driver for UniPhier SoC

On Mon, Jul 30, 2018 at 8:30 AM, Keiji Hayashibara
<hayashibara.keiji@...ionext.com> wrote:
> Hello Trent and Andy,

>> > > +       ckrat = roundup(ckrat, 2);
>> >
>> > ckrat += ckrat & 1;
>>
>> Either way, the compiler produces the same code:
>>
>>  add r0, r0, #1
>>  bic r0, r0, #1
>>
>> I.e., ckrat = (ckrat + 1) & ~1, one "add" and one "and".
>>
>> Might as well use the macro so it's clear. There is also round_up(x,y), which I believe is intended to be used
>> only with power of 2 values of y.
>
> I confirmed round_up() macro.
> This macro is optimized to power of 2 argument,
> and it matches to this case and clear.
>
> I will replace to round_up() macro.

Good!


-- 
With Best Regards,
Andy Shevchenko