Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755275AbcKYPWc (ORCPT ); Fri, 25 Nov 2016 10:22:32 -0500 Received: from mail.free-electrons.com ([62.4.15.54]:43609 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755075AbcKYPWP (ORCPT ); Fri, 25 Nov 2016 10:22:15 -0500 Date: Fri, 25 Nov 2016 16:20:47 +0100 From: Maxime Ripard To: Emmanuel Vadot 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: <20161125152047.oadxi2xbgm4kdd7q@lukather> References: <20161122170616.29557-1-manu@bidouilliste.com> <20161124195517.qrq7briu3pwjnp4n@lukather> <20161124210509.be743aae84c26c6c2e666c6e@bidouilliste.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="pc55j3vdb4tvo6q5" Content-Disposition: inline In-Reply-To: <20161124210509.be743aae84c26c6c2e666c6e@bidouilliste.com> User-Agent: Mutt/1.6.2-neo (2016-08-21) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2287 Lines: 67 --pc55j3vdb4tvo6q5 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable 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: >=20 > > 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. > > >=20 > > > Signed-off-by: Emmanuel Vadot > >=20 > > I don't think we have any code that uses it at the moment. What is the > > rationale behind this patch? > >=20 > > Thanks! > > Maxime > >=20 > > --=20 > > Maxime Ripard, Free Electrons > > Embedded Linux and Kernel engineering > > http://free-electrons.com >=20 > Hi Maxime, >=20 > 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 --=20 Maxime Ripard, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com --pc55j3vdb4tvo6q5 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIcBAEBCAAGBQJYOFbPAAoJEBx+YmzsjxAgaP8P/28+ESng7Bz3M088iP09TH++ XvIcDpcQcirOJ6Rex8RggUFZUPG70iQ3PHNFR2csoSqWgVSVvNatLASxfZ0C7jqj yaR4cnfavOSJgmS+9lv7C+Dqkn6lxkcadrF28UyiP2+AwiHQQG4S564IdSh02QNV V9UeJ4fGt33mYiPMsnieSGnmTiBtd54lvn/3WHbkA9myFNNkgt7qGNt0fase5Kog 7MgUbuSK++oRTiIaSSUo2pV9tZEBBeClErSB4Pnlb036bBFh9+LON1W3ZUFnPoEJ kahntu0HHRVhS8VOj8HkwKKttydPzWN7tjTaKV5ad6eVewKCChgPb3YeWjPy1sZd 6N/vq4+3wt8d/DHWWK68qVjzNLu12ioiHDdrj1JJAdTXwQevuVoBv16FQH62/T0c CnZ980isrHeWOxEM2pSEvfErjUInnZdwUX03EbeMNuaXJqjmsPkizN/tjGbHj/sV blicGqRbE8yctbzvqKQ1LkyC3XmfCOToBBjrZfsjehAFEygltPkYY8+LYTls2E96 4SSt4OpV298CjGPxFJ+U/L9eoPgRwT47L8Bosre622GTsjX7PTy8eQG1usJTf98z yyTpCKcu1nqlhCUmmM0SqHssOUSeugQWqyCKoW3qgP89lDTUppbtxrvrGmv4fVs2 g5wjjiZnOd115d6Kg6ho =7PZw -----END PGP SIGNATURE----- --pc55j3vdb4tvo6q5--