On Thu, Nov 24, 2016 at 09:05:09PM +0100, Emmanuel Vadot wrote: > On Thu, 24 Nov 2016 20:55:17 +0100 > Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx> wrote: > > > On Tue, Nov 22, 2016 at 06:06:16PM +0100, Emmanuel Vadot wrote: > > > The spi0 controller on the A20 have up to 4 CS (Chip Select) while the > > > others three only have 1. > > > Add the num-cs property to each node. > > > > > > Signed-off-by: Emmanuel Vadot <manu@xxxxxxxxxxxxxxxx> > > > > I don't think we have any code that uses it at the moment. What is the > > rationale behind this patch? > > > > Thanks! > > Maxime > > > > -- > > Maxime Ripard, Free Electrons > > Embedded Linux and Kernel engineering > > http://free-electrons.com > > Hi Maxime, > > If num-cs isn't present nothing prevent to start a transfer with a > non-valid CS pin, resulting in an error. > num-cs are default property especially made for this and a SPI driver > should try to get the property at probe/attach time. Yes, but as far as I know, our driver doesn't. I'm all in for having support for that in our driver, but without it, that patch is kind of useless. Maxime -- Maxime Ripard, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com
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