From: Eugene Surovegin <ebs@ebshome.net>
To: Jean-Baptiste Maneyrol <jean-baptiste.maneyrol@teamlog.com>
Cc: linuxppc-embedded@ozlabs.org
Subject: Re: [PATCH] IBM GPIO driver for PowerPC 4xx is back from the dead
Date: Fri, 29 Sep 2006 09:42:45 -0700 [thread overview]
Message-ID: <20060929164245.GA17656@gate.ebshome.net> (raw)
In-Reply-To: <1159515965.5613.4.camel@jb-portable>
On Fri, Sep 29, 2006 at 09:46:04AM +0200, Jean-Baptiste Maneyrol wrote:
> Here is a patch for linux 2.6.18 that makes come back the old ibm gpio
> driver from 2.6.10.
>
> It is mainly useful for compatibility with old linux 2.4 from Montavista
> I think, because direct memory access seems the new way to go.
In my opinion it should stay dead. And no, direct memory access isn't
a way to go - how are you gonna provide synchronization in this case?
Think about different processes mucking with GPIO registers.
I think such low-level functionality should never be exported to the
user-space in the first place. If your user-space needs such access
make it explicit through procfs/sysfs (e.g.
/proc/sys/dev/my_board/reset_that_device for GPIO pin wired to some
chip reset) or just make a specific driver for your hardware.
--
Eugene
next prev parent reply other threads:[~2006-09-29 16:42 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-09-29 7:46 [PATCH] IBM GPIO driver for PowerPC 4xx is back from the dead Jean-Baptiste Maneyrol
2006-09-29 16:42 ` Eugene Surovegin [this message]
-- strict thread matches above, loose matches on Subject: below --
2006-09-29 8:29 Jean-Baptiste Maneyrol
2006-09-29 9:06 ` Arnd Bergmann
2006-09-29 16:46 ` Eugene Surovegin
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