From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753456AbbC0Rw6 (ORCPT ); Fri, 27 Mar 2015 13:52:58 -0400 Received: from mezzanine.sirena.org.uk ([106.187.55.193]:46806 "EHLO mezzanine.sirena.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752903AbbC0Rw4 (ORCPT ); Fri, 27 Mar 2015 13:52:56 -0400 Date: Fri, 27 Mar 2015 10:53:18 -0700 From: Mark Brown To: Michal Simek Cc: linux-kernel@vger.kernel.org, monstr@monstr.eu, =?iso-8859-1?Q?S=F6ren?= Brinkmann , linux-spi@vger.kernel.org, linux-arm-kernel@lists.infradead.org Message-ID: <20150327175318.GG1743@sirena.org.uk> References: <67f3c196833c427a489ca2c530d08987a6b5ee2a.1421412912.git.michal.simek@xilinx.com> <20150308190012.GV28806@sirena.org.uk> <2a81c738-f7e2-4387-b04c-05c9892ba8e4@BN1AFFO11FD026.protection.gbl> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="NY6JkbSqL3W9mApi" Content-Disposition: inline In-Reply-To: <2a81c738-f7e2-4387-b04c-05c9892ba8e4@BN1AFFO11FD026.protection.gbl> X-Cookie: Professional driver on closed track. User-Agent: Mutt/1.5.23 (2014-03-12) X-SA-Exim-Connect-IP: 12.51.221.141 X-SA-Exim-Mail-From: broonie@sirena.org.uk Subject: Re: [PATCH] spi: xilinx: Use standard num-cs binding X-SA-Exim-Version: 4.2.1 (built Mon, 26 Dec 2011 16:24:06 +0000) X-SA-Exim-Scanned: Yes (on mezzanine.sirena.org.uk) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --NY6JkbSqL3W9mApi Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Mar 27, 2015 at 11:55:49AM +0100, Michal Simek wrote: Please fix your mail client to word wrap within paragraphs at less than 80 columns - this makes your mails easier to read and reply to. > On 03/08/2015 08:00 PM, Mark Brown wrote: > > On Fri, Jan 16, 2015 at 01:55:14PM +0100, Michal Simek wrote: > >> Use standard num-cs binding property and setup > >> "xlnx,num-ss-bits" as deprecated. > > Why? These properties mean different things - num-cs is a bit confused > > and is the total number of available chip selects for the system (which > > could include GPIOs) while num-ss-bits is the size of the bitfield > > (which could include things not actually mapped out properly/successful= ly=20 > > or something if the hardware designers were feeling particularly inspir= ed). > I was checking meaning of num-ss-bits and meaning is Number of slaves (ta= king > explanation from Vivado 2014.4) Range 1-32. > http://www.xilinx.com/support/documentation/ip_documentation/axi_spi/v1_0= 2_a/axi_spi_ds742.pdf > Table 1 - page 4 > Checking through the hw design every pin is connected to device to do chi= p select. > That's why I think that num-cs (based on spi-bus.txt) is the right proper= ty. Remember that we can at least in theory have additional chip selects that aren't controlled by the IP block but are instead GPIOs. There's also some potential confusion for users between the number of chip selects in use in a given system and the size of the bitfield that the driver needs to take care of. > > I'm not convinced num-cs ever made any sense. > Does it mean that num-cs property used by 11 SPI drivers is just incorrec= t? > Based on Documentation/devicetree/bindings/spi/spi-bus.txt it is the part= of binding > - num-cs : total number of chipselects > Please let me know what you think. I don't think it has any value. --NY6JkbSqL3W9mApi Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQEcBAEBCAAGBQJVFZkNAAoJECTWi3JdVIfQrKcH/jMOp2MOxZFmapg+SygiCauK ERAz54eOt11RTRHqcvdv3Ump0429tYH9XLaiHMo0qCuQ4EuDEVNPlUUKA6XKdoIM AjA9RIxo9+VbIMKDnsrcSUIpvZ2zmHgU80m8pJ7VoOHud3ZkoChiQKmbFqT1cnI9 VWCRZ/W+7yWA3qgVilXVxIP2zhTVOe8lFWveYKFsOl8EuXUR/4t5UMpiZ85EW73e pvStmB49+3XTOGzcvBlwTA3JluS5TBbrMzhvX2VcSbjf5UhBE1A10CLaKx7JWxtX 7Ceo+NKixMsYuoAeoE8HqafKQfyHlk0v1jDY/wP2MSyNDcuzeBij3h9ZYUqKsyk= =ax01 -----END PGP SIGNATURE----- --NY6JkbSqL3W9mApi--