On 01/15/2012 04:28 PM, Fabio Estevam wrote: > On Sun, Jan 15, 2012 at 10:10 AM, Matthias Fuchs <matthias.fu...@esd.eu> > wrote: > >> That's what I also tried. But from the ref manual I got no idea. >> When we do not find a hy to deassert the chip select manually, we cannot >> avoid this read. > > I was assuming that the chip select deassertion was correctly being > handled by the > mxs_spi_end_xfer function. > > This function handles the LOCK_CS and IGNORE_CRC bits that are > responsible for chip select assertion/deassertion. > > From the MX28 Reference Manual: > > "IGNORE_CRC bit: In SPI/SSI modes: When set to 1, deassert the chip > select (SSn) pin after the command is executed." Exactly. That's the point. It says "... after the command ...". So you need a transfer after calling mxs_spi_end_xfer(). That's why the current code calls it before transferring the final byte.
Matthias > > Then I tought that mxs_spi_end_xfer should be also called in the case > where bitlen==0. In current code this does not happen. > >> It seems that the mainline linux only implements a GPIO based SPI driver. >> So we cannot take it for reference. > > There is no mxs spi driver in the mainline kernel yet. > _______________________________________________ > U-Boot mailing list > U-Boot@lists.denx.de > http://lists.denx.de/mailman/listinfo/u-boot _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
