Thread (43 messages) 43 messages, 11 authors, 2010-07-08

Re: [Uclinux-dist-devel] [PATCH 1/2] mtd: m25p80: Reworkprobing/JEDEC code

From: Barry Song <hidden>
Date: 2010-06-21 10:32:10
Also in: lkml

On Mon, Jun 21, 2010 at 3:39 PM, Anton Vorontsov [off-list ref] w=
rote:
On Mon, Jun 21, 2010 at 03:22:48PM +0800, Barry Song wrote:
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On Mon, Jun 21, 2010 at 3:15 PM, Anton Vorontsov <cbouatmailru@gmail.com=
wrote:
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On Mon, Jun 21, 2010 at 11:27:31AM +0800, Barry Song wrote:
[...]
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How about we add a non_jedec flag in platform_data, if the flag is =
1, we
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let the detection pass even though the ID is 0? Otherwise, we need =
a
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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.
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Only if non_jedec=3D1, we let the detection pass
if ID is 0.
Then please #ifdef it with CONFIG_OF.
I think the patch has nothing to do with platform. Here SPI Flash is a
peripherals, doesn't depend on any platform. Adding a CONFIG_OF
doesn't make sense very much.
If you think most devices are non-JEDEC, we can change non_JEDEC to
force_JEDEC as you said. But anyway, is that real that most devices
are non_JEDEC?  If not, I think we should change OF platform codes to
fit with this patch.
Thanks,
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Index: drivers/mtd/devices/m25p80.c
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
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--- drivers/mtd/devices/m25p80.c =C2=A0 =C2=A0 =C2=A0(revision 8927)
+++ drivers/mtd/devices/m25p80.c =C2=A0 =C2=A0 =C2=A0(revision 8929)
@@ -795,8 +795,13 @@
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 jid =3D jedec_probe(=
spi);
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=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 if (!jid) {
- =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=
=A0 dev_info(&spi->dev, "non-JEDEC variant of %s\n",
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- =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=
=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0id->name);
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+ =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=
=A0 if (!data->non_jedec) {
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+ =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=
=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 dev_err(&spi->dev, "fail to detect%s\n",
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+ =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=
=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =
=C2=A0 =C2=A0 id->name);
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+ =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=
=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 return -ENODEV;
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+ =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=
=A0 } else
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+ =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=
=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 dev_info(&spi->dev, "non-JEDEC variant of %=
s\n",
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+ =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=
=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =
=C2=A0 =C2=A0 id->name);
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=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 } else if (jid !=3D =
id) {
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--
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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