[lkml]   [2008]   [Sep]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: [MMC] Multiple cards on one host
    On Wed, 3 Sep 2008 10:43:43 +0200
    Sascha Hauer <> 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?

    -- Pierre Ossman

    Linux kernel, MMC maintainer
    rdesktop, core developer

    WARNING: This correspondence is being monitored by the
    Swedish government. Make sure your server uses encryption
    for SMTP traffic and consider using PGP for end-to-end

     \ /
      Last update: 2008-09-03 16:13    [W:0.040 / U:11.900 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site