From: Arnd Bergmann <arnd@arndb.de>
To: Hartley Sweeten <HartleyS@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Amitoj Kaur Chawla <amitoj1606@gmail.com>,
        Bhaktipriya Shridhar <bhaktipriya96@gmail.com>,
        "devel@driverdev.osuosl.org" <devel@driverdev.osuosl.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] staging/comedi/dt282x: avoid integer overflow warning
Date: Wed, 16 Mar 2016 21:52:30 +0100
Message-ID: <292158977.4HS03to08B@wuerfel>
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On Wednesday 16 March 2016 17:04:15 Hartley Sweeten wrote:
> > #define DT2821_SUPCSR_DS_AD_TRIG       (3 << 10)
> 
> Use a helper macro for those bits:
> 
> #define DT2821_SUPCSR_DS(x)             (((x) & 0x3) << 10)
> #define DT2821_SUPCSR_DS_PIO            DT2821_SUPCSR_DS(0)
> #define DT2821_SUPCSR_DS_AD_CLK         DT2821_SUPCSR_DS(1)
> #define DT2821_SUPCSR_DS_DA_CLK         DT2821_SUPCSR_DS(2)
> #define DT2821_SUPCSR_DS_AD_TRIG                DT2821_SUPCSR_DS(3)
> 
> > I considered using BIT() but decided against it for consistency.
> 
> Your change may fix the gcc-6 issue but it doesn't fix the 28 checkpatch.pl
> issues:
> CHECK: Prefer using the BIT macro

I sent a new version now, and found a better solution that avoids
using BIT().

	Arnd