On Fri, 25 Nov 2016 16:20:47 +0100 Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx> wrote: > 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 Yes the Linux driver doesn't use it but my upcoming one for FreeBSD uses it. So it is not useless for downstream user of DTS. Cheers, -- Emmanuel Vadot <manu@xxxxxxxxxxxxxxxx> <manu@xxxxxxxxxxx> -- 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
