On Friday 07 March 2008, Joakim Tjernlund wrote: > Restoring speed & wordsize on mpc83xx disables the controller temporarily > which makes the SPI outputs floating. This can cause a glich on > the SPI CLK which makes the slave in the other end unhappy.
This will also cause trouble with any driver using these protocol tweaking options: - per-transfer overrides of speed and/or wordsize - leaving chip selected between messages The mpc83xx driver is not overriding master->transfer, so all of those are behaviors this driver claims to support... > Make sure that CS is disabled before restoring speed & wordsize > so any gliches are ignored by the SPI slave. I think the correct fix hast to be in mpc83xx_spi_setup_transfer(). If that routine is fixed, the bitbang core won't need to change, and those protocol tweaking options will just work. Or else, this patch would need to be accompanied by a patch which updates spi_mpc83xx to override master->transfer and filter out all messages which use those protocol tweaking options, so that all the places this glitch can appear will be addressed. - Dave ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. 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
