Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755098AbcLAKYU (ORCPT ); Thu, 1 Dec 2016 05:24:20 -0500 Received: from mail.blih.net ([212.83.177.182]:37544 "EHLO mail.blih.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751164AbcLAKYS (ORCPT ); Thu, 1 Dec 2016 05:24:18 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=bidouilliste.com; h=date :from:to:cc:subject:message-id:in-reply-to:references :mime-version:content-type:content-transfer-encoding; q=dns; s= mail; b=P2Kpl9HQ0bNy4/rPbjMe/PXN8iVcD/wsMqWCHEL2/Fm2/KjRnuS+CUg7 nbtQnsXx8IooW37Ge0guTSiWLUCi+tiG7+dAtr0TS7uNnuuTfgt3ckq+eCO1ezZf MLZOD8snr00TwguYedi/vvwcMKrPdjikUwX9E5fEm0QBicIt7nQ= Date: Thu, 1 Dec 2016 11:24:14 +0100 From: Emmanuel Vadot To: Maxime Ripard Cc: mark.rutland@arm.com, devicetree@vger.kernel.org, linux@armlinux.org.uk, linux-kernel@vger.kernel.org, wens@csie.org, robh+dt@kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH] ARM: dts: sunxi: Add num-cs for A20 spi nodes Message-Id: <20161201112414.62f9b351186115f62c8998a9@bidouilliste.com> In-Reply-To: <20161201092150.rlo5skxd6elovlgq@lukather> References: <20161122170616.29557-1-manu@bidouilliste.com> <20161124195517.qrq7briu3pwjnp4n@lukather> <20161124210509.be743aae84c26c6c2e666c6e@bidouilliste.com> <20161125152047.oadxi2xbgm4kdd7q@lukather> <20161125220752.c989c85e01ed202be0485c78@bidouilliste.com> <20161201092150.rlo5skxd6elovlgq@lukather> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.29; amd64-portbld-freebsd11.0) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2469 Lines: 72 Hi Maxime, On Thu, 1 Dec 2016 10:21:50 +0100 Maxime Ripard wrote: > Hi Emmanuel, > > On Fri, Nov 25, 2016 at 10:07:52PM +0100, Emmanuel Vadot wrote: > > On Fri, 25 Nov 2016 16:20:47 +0100 > > Maxime Ripard 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 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. > > > > 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. > > Ah, I didn't know this was for FreeBSD. So you started to use our DTs, > or do you have some modifications to it? How does that work? Yes we use the DTS from linux from quite some times now. We're currently synced with 4.7-ish. We either use them directly or modify them according to our needs and driver support. > Anyway, the fact that it isn't used by our driver at the moment and > that it's meant for other OSes should be mentionned in the commit log. Yeah I understand, I'll send a v2 with this in the commit log. > Thanks! > Maxime > > -- > Maxime Ripard, Free Electrons > Embedded Linux and Kernel engineering > http://free-electrons.com -- Emmanuel Vadot