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Message-Id: <200807111453.20162.mb@bu3sch.de>
Date: Fri, 11 Jul 2008 14:53:19 +0200
From: Michael Buesch <mb@...sch.de>
To: David Brownell <david-b@...bell.net>
Cc: Jiri Slaby <jirislaby@...il.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Stephen Rothwell <sfr@...b.auug.org.au>, mchehab@...radead.org,
linux-kernel <linux-kernel@...r.kernel.org>,
Marcel Holtmann <marcel@...tmann.org>
Subject: Re: [PATCH v3] Add bt8xxgpio driver
On Thursday 10 July 2008 22:02:12 David Brownell wrote:
> See Documentation/gpio.txt:
>
> + Note that these operations include I/O barriers on platforms
> + which need to use them; drivers don't need to add them explicitly.
>
> That's the key thing: drivers using I/O calls should
> not need to insert bus or platform specific calls to
> make sure the calls take effect.
Well, as I said, I am OK with an I/O-barrier, which is mmiowb().
But flushing, by reading the register back, is not acceptable for
me in this case, unless someone can show me hardware that needs this.
And even then I'd implement the flushing only conditionally for
that hardware.
--
Greetings Michael.
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