Messages in this thread | | | Date | Wed, 3 Sep 2008 16:11:02 +0200 | From | Pierre Ossman <> | Subject | Re: [MMC] Multiple cards on one host |
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On Wed, 3 Sep 2008 10:43:43 +0200 Sascha Hauer <s.hauer@pengutronix.de> wrote:
> Hi, > > I have a board (PXA based) which has two SD slots. It uses a gpio to > switch between the slots. In times when the MMC subsystem implemented > the bus topology our customer used this fact to connect the two slots on > a single host (although it was never intended to work with SD cards, it > seemed to work). Any idea how to implement this on recent kernels? I > thought about registering two hosts in pxamci.c, but this seems quite > hacky and I suppose I'll run into locking trouble. >
To be honest, I don't think you can sanely support it. The OMAP guys have been playing with some kind of multiplexer in front of the controller, but it just seems like a world of hurt to me.
Perhaps you can convert to using SPI for the second slot if the customer really needs a design with two slots?
Rgds -- -- Pierre Ossman
Linux kernel, MMC maintainer http://www.kernel.org rdesktop, core developer http://www.rdesktop.org
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