On Thursday 03 January 2008, Gernot Kvas wrote:
> Hello,
> 
> I have implemented a DMA/PIO driven SPI driver for the ARM based
> ns9xxx SoCs, largely based on the driver for the omap2. I'm using the
> mmc_spi stuff from the mm patches, currently 2.6.23-mm1.

ISTR some initial merge glitches, but maybe they were gone by then.
I'd still recommend using more current code; especially with the
2.6.24 release nearly upon us.  :)


>                Apart from a 
> small patch to the UNSTUFF_BITS macro in drivers/mmc/core/mmc.c to
> resolve some endianess issues, it works like a charm (for reading).
> The card gets properly detected, I can mount it and read files from it
> at a decent speed.

That's good to know!


> However, when I try to write to it, it fails. I used a scope to
> monitor all 4 lines and discovered that after a CMD25 or CMD24, a

That is, after WRITE_MULTIPLE_BLOCK or WRITE_BLOCK ...


> subsequent CMD25 or CMD24 would fail. Both commands expect a R1
> response, 8-bits. However, prior to what looks like a 8-bit response,
> I read a couple of 0xFF (which is normal) and then suddenly a 0xFE. It
> seems as if the card goes low too early. Any ideas, hints?

That sounds a bit familiar.  Does that happen with all cards, or
just with ones from one particular vendor?  Is that driver version
using SPI_MODE_0 or SPI_MODE_3?

And is your SPI controller driver keeping chipselect low during
that whole period?

- Dave


-------------------------------------------------------------------------
This SF.net email is sponsored by: Microsoft
Defy all challenges. Microsoft(R) Visual Studio 2005.
http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/
_______________________________________________
spi-devel-general mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/spi-devel-general

Reply via email to