From mboxrd@z Thu Jan  1 00:00:00 1970
From: Wolfram Sang <wsa@the-dreams.de>
Subject: Re: [RFC 0/2] i2c: sh_mobile: don't regress on deferred probing
Date: Wed, 10 Dec 2014 15:19:12 +0100
Message-ID: <20141210141912.GA8247@katana>
References: <1418217709-26392-1-git-send-email-wsa@the-dreams.de>
 <CAMuHMdUwsUakz7S_7xCob4__wR-PXcdpZKTGx0i_6ZatDeSvXg@mail.gmail.com>
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To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Linux I2C <linux-i2c@vger.kernel.org>, Linux-sh list <linux-sh@vger.kernel.org>, Magnus Damm <magnus.damm@gmail.com>, Simon Horman <horms@verge.net.au>, Laurent Pinchart <laurent.pinchart@ideasonboard.com>
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> On Wed, Dec 10, 2014 at 2:21 PM, Wolfram Sang <wsa@the-dreams.de> wrote:
> > Okay, here is my take on solving the problem found by Geert. I still do=
n't like
> > it much but it is not as bad as I expected it to be ;) Let me know what=
 you
> > think.
>=20
> Thanks, it's indeed less ugly than I would have expected ;-)

:D

> Note that in spi-rspi.c and spi-sh-msiof, any error returned by *_request=
_dma()
> is considered an error, and -EPROBE_DEFER is not handled specially.
> So it won't retry if the DMA engine driver isn't available, but just use =
PIO
> (until unbind/bind).

For historic reasons, i2c-sh_mobile uses subsys_initcall() and at that
time, DMA is never available. Converting to module_init() will just
create its own set of potential regressions :(

> Now we have a nice sample implementation, perhaps I should port it to
> spi-rspi and spi-sh-msiof, too?
>=20
> Let's wait and see for other comments...

Yeah, let's see first...


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