Re: PXA270 SPI + SD card

[Baruch Siach <baruch-NswTu9S1W3P6gbPvEgmw2w@public.gmane.org>]

Hi Cliff,

On Wed, Nov 04, 2009 at 04:54:18PM -0500, Cliff Brake wrote:
> Also, what SPI mode is typically used for SD?  Looks like 0 and 3 are
> the closest (http://elm-chan.org/docs/spi_e.html).

I've found this in drivers/mmc/host/mmc_spi.c:mmc_spi_probe():

        /* MMC and SD specs only seem to care that sampling is on the
         * rising edge ... meaning SPI modes 0 or 3.  So either SPI mode
         * should be legit.  We'll use mode 0 since the steady state is 0,
         * which is appropriate for hotplugging, unless the platform data
         * specify mode 3 (if hardware is not compatible to mode 0).
         */
        if (spi->mode != SPI_MODE_3)
                spi->mode = SPI_MODE_0;

baruch

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