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    SubjectRE: [patch] split MMC_CAP_4_BIT_DATA


    I'd like to say something about this issue.
    Currently,the blackfin on chip SD host ONLY support 1-bit MMC while
    support 1-bit/4-bit SD/SDIO.
    And we want our driver to support both 1-bit MMC and 4-bit SD/SDIO.but
    the current MMC driver framework
    Only allow us to set one kind of bus width,either 1-bit or 4-bit.So in
    order to meet our case,we need more flexible mechanism
    To inform the upper commom driver to know our situation.


    -----Original Message-----
    From: Bryan Wu []
    Sent: Wednesday, January 09, 2008 10:33 AM
    To: Pierre Ossman;
    Cc: Mike Frysinger;
    Subject: Re: [patch] split MMC_CAP_4_BIT_DATA

    On Jan 9, 2008 4:49 AM, Pierre Ossman <> wrote:
    > On Tue, 8 Jan 2008 14:40:49 -0500
    > Mike Frysinger <> wrote:
    > >
    > > i dont understand what's confusing. the Blackfin on chip host
    > > controller only supports 1-bit MMC, but it supports 4-bit SD/SDIO.
    > > this is a fact. while it may be a stupid decision, it is what it
    > > is, and i need the framework made more flexible in order to get the
    > > Blackfin driver merged cleanly. we do software for hardware, we
    dont do hardware.
    > Well, since I've seen no _hardware_ differences between 4-bit MMC and
    4-bit SD, "support" in this case must me "vendor will guarantee it
    works". And that is not the kind of "support" that needs a distinction
    in the code.
    > So, again, if you feel that there is a hardware difference between
    4-bit MMC and 4-bit SD then please elaborate as it is my understanding
    that they are identical.

    As Mike said, the reason split this flag is because Blackfin on-chip
    SDIO controller's limitation.
    Cliff is working on it for a long time, so I dropped him in. Hope he can
    clarify the confusing things.

    -Bryan Wu

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