Messages in this thread |  | | | Subject | RE: [patch] split MMC_CAP_4_BIT_DATA | | Date | Wed, 9 Jan 2008 11:21:40 +0800 | | From | "Cai, Cliff" <> |
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Hi,all
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.
Cliff
-----Original Message----- From: Bryan Wu [mailto:cooloney.lkml@gmail.com] Sent: Wednesday, January 09, 2008 10:33 AM To: Pierre Ossman; cliff.cai@analog.com Cc: Mike Frysinger; linux-kernel@vger.kernel.org Subject: Re: [patch] split MMC_CAP_4_BIT_DATA On Jan 9, 2008 4:49 AM, Pierre Ossman <drzeus-mmc@drzeus.cx> wrote: > On Tue, 8 Jan 2008 14:40:49 -0500 > Mike Frysinger <vapier.adi@gmail.com> 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.
Thanks -Bryan Wu
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