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    SubjectRe: [Uclinux-dist-devel] [PATCH 1/2] mtd: m25p80: Reworkprobing/JEDEC code
    On Mon, Jun 21, 2010 at 12:47, Anton Vorontsov wrote:
    > On Mon, Jun 21, 2010 at 12:34:05PM -0400, Mike Frysinger wrote:
    >> On Mon, Jun 21, 2010 at 07:20, Anton Vorontsov wrote:
    >> > You can't easily change OF. It's like "let's change ACPI tables
    >> > or BIOS in these PCs". Doable, but involves things like reflashing.
    >> > And we usually have to support old BIOSes as well.
    >> >
    >> > OTOH, I see (git grep m25p arch/powerpc/boot/dts/) that in
    >> > mainline kernel only MPC8569 board has a correct m25p
    >> > node, and it is STMicro variant (it is JEDEC capable).
    >> >
    >> > As we don't really have to support out of tree code, I'd
    >> > just go with this patch, assuming that we have to change
    >> > device tree for boards with non-JEDEC flashes. It's
    >> > effectively the same thing as platform data flag, except
    >> > that it works automatically for OF platforms.
    >> >
    >> > diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c
    >> > index 81e49a9..a610ca9 100644
    >> > --- a/drivers/mtd/devices/m25p80.c
    >> > +++ b/drivers/mtd/devices/m25p80.c
    >> > @@ -680,6 +680,16 @@ static const struct spi_device_id m25p_ids[] = {
    >> >        { "m25p64",  INFO(0x202017,  0,  64 * 1024, 128, 0) },
    >> >        { "m25p128", INFO(0x202018,  0, 256 * 1024,  64, 0) },
    >> >
    >> > +       { "m25p05-nonjedec",  INFO(0, 0,  32 * 1024,   2, 0) },
    >> > +       { "m25p10-nonjedec",  INFO(0, 0,  32 * 1024,   4, 0) },
    >> > +       { "m25p20-nonjedec",  INFO(0, 0,  64 * 1024,   4, 0) },
    >> > +       { "m25p40-nonjedec",  INFO(0, 0,  64 * 1024,   8, 0) },
    >> > +       { "m25p80-nonjedec",  INFO(0, 0,  64 * 1024,  16, 0) },
    >> > +       { "m25p16-nonjedec",  INFO(0, 0,  64 * 1024,  32, 0) },
    >> > +       { "m25p32-nonjedec",  INFO(0, 0,  64 * 1024,  64, 0) },
    >> > +       { "m25p64-nonjedec",  INFO(0, 0,  64 * 1024, 128, 0) },
    >> > +       { "m25p128-nonjedec", INFO(0, 0, 256 * 1024,  64, 0) },
    >> > +
    >>
    >> are you picking the m25p because its flash geometry matches whatever
    >> you're using, or because you have some weird variant of the m25p that
    >> has JEDEC commands removed ?
    >
    > The latter. It's Numonyx M25Pxx flashes, see
    > http://www.numonyx.com/Documents/Datasheets/M25P80.pdf
    >
    >   The RDID instruction is available only for parts made with 110
    >   nm Technology identified with Process letter '4'.

    lovely. i guess this patch is the way to go to satisfy everyone's
    requirements. i'm also of the mindset that a mtd should not be
    created if the SPI flash isnt there simply because the resources say
    it might be.
    -mike
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