Point to sample SPI for MMC card driver?
Robert S. Grimes
rsg at alum.mit.edu
Wed Oct 15 18:50:13 UTC 2008
Gene Smith wrote:
> I noticed that Robert S. Grimes seems to have finished his SPI driver
> and he started with something in vertex BSP. The threads he started have
> a lot of good information in them. Also, the README_libi2c is probably
> the best and most thorough I have seen in RTEMS.
>
Yes, README_libi2c is very thorough; there were several times that, upon
re-reading it, I understood things even better...
> I am looking for some code to use as a starting point for writing my SPI
> driver, which does not correspond to any existing BSP. I see that often
> the SPI driver is divided between libcpu and libbsp.
Yes - the reasons being explained in earlier posting by Thomas Doerfler
and, of course, the README_libi2c.
> However, I probably would want to put all the low level stuff in just my libbsp if possible. I found something under libbsp/m68k/gen68360/spi that appears to be the
> complete driver(s) (files m360_spi.c and mc68360_spidrv.c). Would these be OK to use as a template? Or should I look somewhere else for a better example?
>
Sorry, can't help you here, but you do want to be fairly current. The
libi2c SPI support has matured somewhat since I started (around 4.8),
and if you want to use the spi-sd-card driver, you'll need to make sure
you're based on at least 4.9 libi2c. In particular, you'll want to
support the idle_char field of the transfer parameters structure
rtems_libi2c_tfr_mode_t. See my latest posts regarding "Card Specific
Data".
FWIW - I started with the powerpc/mpc5566evb SPI driver, as Sebastian
suggested - I think you know the thread...
Take care,
-Bob
P.S. Feel free to ask questions - it's still pretty fresh in my mind...
> Thanks,
> -gene
>
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