linux-kernel - Re: [PATCH] staging: fbtft: Replace a bit shift by a use of BIT.

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Message-ID: <CAHp75Vd7A8vYLO4OdELCDhFkAy-nqC+rsRuhn=KrD9spm_SSkw@mail.gmail.com>
Date:   Wed, 22 Mar 2017 18:22:19 +0200
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Arushi Singhal <arushisinghal19971997@...il.com>
Cc:     Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        devel@...verdev.osuosl.org,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        outreachy-kernel@...glegroups.com
Subject: Re: [PATCH] staging: fbtft: Replace a bit shift by a use of BIT.

On Wed, Mar 22, 2017 at 6:18 PM, Andy Shevchenko
<andy.shevchenko@...il.com> wrote:
> On Wed, Mar 22, 2017 at 4:37 AM, Arushi Singhal
> <arushisinghal19971997@...il.com> wrote:
>> This patch replaces bit shifting on 1 with the BIT(x) macro.
>> This was done with coccinelle:
>> @@
>> constant c;
>> @@
>>
>> -1 << c
>> +BIT(c)
>>
>
> While using BIT() macro is a good idea, you make it inconsistent here.
> There are at least two options:
> - do nothing
> - define _MASK:s with GENMASK() and reuse in the code (looking at the
> code they are masks, not just separate bits).

Looking a bit more, not masks, but values.
So, best would be define for bits and values like 0x17.

One more thing, you don't need extra parens surround BIT() macro.

-- 
With Best Regards,
Andy Shevchenko