On Wed, Jul 22, 2015 at 1:15 PM, Zhi Li <lznuaa@xxxxxxxxx> wrote: > On Mon, Aug 4, 2014 at 9:25 AM, Mark Brown <broonie@xxxxxxxxxx> wrote: >> On Sat, Aug 02, 2014 at 11:09:09AM +0200, Geert Uytterhoeven wrote: >>> On Sat, Aug 2, 2014 at 4:06 AM, Brian Norris >>> > On Wed, Jul 30, 2014 at 11:46:07AM +0100, Mark Brown wrote: >> >>> >> I don't know what DDR is in this context, sorry. >> >>> > I think it's just the ability to latch data on both the rising and >>> > falling edges of the SPI clock. For SPI flash, it seems to be used for >>> > the data portion of the opcode/address/data sequence. >> >>> > Yeah, I suppose it could be wedged in later if drivers/spi/ ever adopts >>> > a solution. >> >>> I think this can just be another SPI_* spi_device.mode flag. >> >> Sounds like it yes - I was wondering if this might be one of the modes >> with extra clock cycles that I've heard mentioned before which might be >> a little more fun. >> >>> Do we need bindings for this in >>> Documentation/devicetree/bindings/spi/spi-bus.txt? >>> Unlike Quad SPI transfer support, this doesn't need special wiring, so DDR >>> capability is an intrinsic property of the SPI slave, and the mode bit can just >>> be set in the SPI slave driver, without any DT magic? >> >> Right, unless we run into things like board design issues causing >> constraints this is something that can be enabled by the two drivers >> without needing DT configuration. > > All: Just update shijie's email address. > > we plan resume this work. > I need direction how go ahead further. > > I go through this email thread. > > The discussion focus on how to get dummy cycle information. > > Shijie get it from DT. > > Brain suggest get from CFI or map id table if I understand correct. > > Accodring to spec > http://www.spansion.com/Support/Datasheets/S25FL128S_256S_00.pdf > > Table 8.10 > > Dummy cycle depend on frequency, read command. > > if information saved in driver, it will be huge table. > >> >> _______________________________________________ >> linux-arm-kernel mailing list >> linux-arm-kernel@xxxxxxxxxxxxxxxxxxx >> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >> -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
