Date: Wed, 27 Sep 2006 15:42:08 -0700
From: Andrew Morton <akpm@osdl.org>
To: "Miguel Ojeda" <maxextreme@gmail.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2.6.18 real-V5] drivers: add lcd display support
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On Wed, 27 Sep 2006 20:58:24 +0000
"Miguel Ojeda" <maxextreme@gmail.com> wrote:

> On 9/26/06, Andrew Morton <akpm@osdl.org> wrote:
> > It's also probably-incorrect on big-endian CPUs.
> > Perhaps you should not
> > use bitops at all for this driver, use open-coded |
> > and &/~ instead?
> 
> Uhm, someone told me that they shouldn't be used because the kernel
> has generic functions for that.

You can't believe everything you read on the internet ;)

set_bit() and friends are a) atomic wrt other CPUs on SMP and b) only to be
performed on unsigned longs.

> I researched the kernel sources, and looking at bitops.h I found
> setbit(), so I tried to use it in the driver, althought I prefer
> standard |= and &=.

Those are the appropriate operations to use in this driver.

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