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From: Phil Sutter <n0-1@freewrt.org>
To: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: ralf@linux-mips.org, sshtylyov@ru.mvista.com, linux-mips@linux-mips.org
Subject: Re: [PATCH] MIPS: rb532: fix bit swapping in rb532_set_bit()
Date: Mon, 3 Nov 2008 16:05:42 +0100	[thread overview]
Message-ID: <20081103150542.GB13461@nuty> (raw)
In-Reply-To: <20081103.234856.61509468.anemo@mba.ocn.ne.jp>

Hi,

On Mon, Nov 03, 2008 at 11:48:56PM +0900, Atsushi Nemoto wrote:
> Well, the linux gpio framework uses 0 for low, _nonzero_ for high.
> You should not assume the bitval is 0 or 1.

Good point. I was thinking about this potential problem, too. This is
why the mentioned function contains the following line (sadly too far
off to occur in the patch):

| bitval = !!bitval;              /* map parameter to {0,1} */

I put that separately to not make the below lines even more unreadable.

> 	val &= ~(!bitval << offset);   /* unset bit if bitval == 0 */
> 	val |= (!!bitval << offset);   /* set bit if bitval != 0 */

But as a boolean inverse has to be used anyway, your solution looks more
elegant than mine.

Greetings, Phil

  reply	other threads:[~2008-11-03 15:04 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-10-29 20:00 [PATCH] provide functions for gpio configuration Phil Sutter
2008-10-29 20:07 ` Florian Fainelli
2008-10-29 21:10   ` Phil Sutter
2008-10-30 17:13     ` Florian Fainelli
2008-10-30 17:47       ` Phil Sutter
2008-10-30 18:16         ` Florian Fainelli
2008-10-30 20:20           ` Phil Sutter
2008-10-30 20:26             ` Florian Fainelli
2008-10-31  0:25             ` [PATCH] add prototypes for the exported symbols Phil Sutter
2008-10-31 14:58               ` [PATCH] provide functions for gpio configuration Phil Sutter
2008-11-02 21:56                 ` Sergei Shtylyov
2008-11-03 14:29                   ` Phil Sutter
2008-11-03 14:30                     ` [PATCH] MIPS: rb532: fix bit swapping in rb532_set_bit() Phil Sutter
2008-11-03 14:48                       ` Atsushi Nemoto
2008-11-03 15:05                         ` Phil Sutter [this message]
2008-11-11 23:09                           ` Phil Sutter
2009-01-29 16:27                             ` Ralf Baechle
  -- strict thread matches above, loose matches on Subject: below --
2008-11-11 23:14 Phil Sutter
2008-11-11 23:26 ` Phil Sutter

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