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Date: Mon, 21 Jun 2010 11:39:09 +0400
From: Anton Vorontsov <cbouatmailru@gmail.com>
To: Barry Song <21cnbao@gmail.com>
Cc: "Song, Barry" <Barry.Song@analog.com>,
       David Brownell <dbrownell@users.sourceforge.net>,
       Artem Bityutskiy <dedekind1@gmail.com>, linux-kernel@vger.kernel.org,
       linuxppc-dev@ozlabs.org, linux-mtd@lists.infradead.org,
       uclinux-dist-devel@blackfin.uclinux.org,
       Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [Uclinux-dist-devel] [PATCH 1/2] mtd: m25p80:
 Reworkprobing/JEDEC code
Message-ID: <20100621073909.GA20674@oksana.dev.rtsoft.ru>
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On Mon, Jun 21, 2010 at 03:22:48PM +0800, Barry Song wrote:
> On Mon, Jun 21, 2010 at 3:15 PM, Anton Vorontsov <cbouatmailru@gmail.com> wrote:
> > On Mon, Jun 21, 2010 at 11:27:31AM +0800, Barry Song wrote:
> > [...]
> >> > How about we add a non_jedec flag in platform_data, if the flag is 1, we
> >> > let the detection pass even though the ID is 0? Otherwise, we need a
> >> > valid ID?
> >> Here i mean:
> >
> > This will break at least OF-enabled platforms (e.g. PowerPC),
> > they assume that the driver will success for non-JEDEC flashes.
> > OF platforms don't pass platform data, and even if they did,
> > device tree doesn't specify if the flash is JEDEC or non-JEDEC.
> >
> > Which is why I think that, by default, the driver should
> > successfully register the flash even if JEDEC probe fails. So,
> > instead of checking for "!non_jedec", I would recommend
> > "force_jedec" check.
> 
> Mike Frysinger suggested to use non_jedec since most devices are
> standard jedec devices.

Well, on OF platforms most devices that I'm aware of are non-JEDEC.

> Only if non_jedec=1, we let the detection pass
> if ID is 0.

Then please #ifdef it with CONFIG_OF.

Thanks,

> >> Index: drivers/mtd/devices/m25p80.c
> >> ===================================================================
> >> --- drivers/mtd/devices/m25p80.c      (revision 8927)
> >> +++ drivers/mtd/devices/m25p80.c      (revision 8929)
> >> @@ -795,8 +795,13 @@
> >>
> >>               jid = jedec_probe(spi);
> >>               if (!jid) {
> >> -                     dev_info(&spi->dev, "non-JEDEC variant of %s\n",
> >> -                              id->name);
> >> +                     if (!data->non_jedec) {
> >> +                             dev_err(&spi->dev, "fail to detect%s\n",
> >> +                                             id->name);
> >> +                             return -ENODEV;
> >> +                     } else
> >> +                             dev_info(&spi->dev, "non-JEDEC variant of %s\n",
> >> +                                             id->name);
> >>               } else if (jid != id) {
> >
> > --
> > Anton Vorontsov
> > email: cbouatmailru@gmail.com
> > irc://irc.freenode.net/bd2
> >

-- 
Anton Vorontsov
email: cbouatmailru@gmail.com
irc://irc.freenode.net/bd2
--
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