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Date: Fri, 10 Mar 2017 07:06:30 -0600
From: Segher Boessenkool <segher@kernel.crashing.org>
To: Christophe LEROY <christophe.leroy@c-s.fr>
Cc: Michael Ellerman <mpe@ellerman.id.au>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>, Scott Wood <oss@buserror.net>,
        linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] powerpc: sysdev: cpm1: Optimise gpio bit calculation
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On Fri, Mar 10, 2017 at 11:54:19AM +0100, Christophe LEROY wrote:
> gpio_get() and gpio_set() are used extensively by some GPIO based 
> drivers like SPI, NAND, so it may be worth it as it doesn't impair 
> readability (if anyone prefers, we could write  (1 << 31) >> i  instead 
> of  0x80000000 >> i )

1 << 31 is undefined behaviour, of course.


Segher