On Fri, Sep 23, 2016 at 04:03:57AM +0300, Siarhei Siamashka wrote: > On Thu, 22 Sep 2016 23:52:52 +0200 > Danny Milosavljevic <[email protected]> wrote: > > > Hello, > > > > when using SPI on Allwinner A20 with CPOL=1 and CPHA=1 with Linux 4.8.0-rc6 > > Psychotic Stoned Sheep I see a weird dip in the beginning (which also > > confuses the slave) on the SCLK line right when SSEL goes low - see > > attachment. > > > > The lines are, starting from the top, SCLK MOSI MISO SSEL. > > > > I'm using spidev. > > > > Did anyone see this problem before? > > Hi, > > I'm not sure, but something like this might be somehow related: > https://patchwork.kernel.org/patch/7960811/ > > As a random thing to check, I would also advise to verify the > pull-up/pull-down settings for the SCLK pin. > > And maybe as another test, change the driver to automatically > drive the SSEL pin instead of doing this manually.
We cannot do that, this would break the framework's expectations with the behaviour you're suposed to have in set_cs (which is why we ended up using the manual mode), and especially that it's supposed to happen right away and control the logical level of the CS line. Maxime -- Maxime Ripard, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com -- You received this message because you are subscribed to the Google Groups "linux-sunxi" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
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