From mboxrd@z Thu Jan 1 00:00:00 1970 From: maxime.ripard@free-electrons.com (Maxime Ripard) Date: Fri, 25 Nov 2016 16:20:47 +0100 Subject: [PATCH] ARM: dts: sunxi: Add num-cs for A20 spi nodes In-Reply-To: <20161124210509.be743aae84c26c6c2e666c6e@bidouilliste.com> References: <20161122170616.29557-1-manu@bidouilliste.com> <20161124195517.qrq7briu3pwjnp4n@lukather> <20161124210509.be743aae84c26c6c2e666c6e@bidouilliste.com> Message-ID: <20161125152047.oadxi2xbgm4kdd7q@lukather> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thu, Nov 24, 2016 at 09:05:09PM +0100, Emmanuel Vadot wrote: > On Thu, 24 Nov 2016 20:55:17 +0100 > Maxime Ripard 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 > > > > 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 -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 801 bytes Desc: not available URL: