From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752361AbbC0K4J (ORCPT ); Fri, 27 Mar 2015 06:56:09 -0400 Received: from mail-by2on0079.outbound.protection.outlook.com ([207.46.100.79]:15648 "EHLO na01-by2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751715AbbC0K4F (ORCPT ); Fri, 27 Mar 2015 06:56:05 -0400 Date: Fri, 27 Mar 2015 11:55:49 +0100 From: Michal Simek User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.5.0 MIME-Version: 1.0 To: Mark Brown , Michal Simek CC: , , =?windows-1252?Q?S=F6?= =?windows-1252?Q?ren_Brinkmann?= , , Subject: Re: [PATCH] spi: xilinx: Use standard num-cs binding References: <67f3c196833c427a489ca2c530d08987a6b5ee2a.1421412912.git.michal.simek@xilinx.com> <20150308190012.GV28806@sirena.org.uk> In-Reply-To: <20150308190012.GV28806@sirena.org.uk> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-RCIS-Action: ALLOW X-TM-AS-Product-Ver: IMSS-7.1.0.1224-7.5.0.1018-21428.005 X-TM-AS-User-Approved-Sender: Yes;Yes;Yes Message-ID: <2a81c738-f7e2-4387-b04c-05c9892ba8e4@BN1AFFO11FD026.protection.gbl> X-EOPAttributedMessage: 0 Authentication-Results: spf=pass (sender IP is 149.199.60.83) smtp.mailfrom=michal.simek@xilinx.com; kernel.org; dkim=none (message not signed) header.d=none; X-Forefront-Antispam-Report: CIP:149.199.60.83;CTRY:US;IPV:NLI;EFV:NLI;BMV:1;SFV:NSPM;SFS:(10009020)(6009001)(438002)(189002)(377454003)(51704005)(243025005)(51444003)(164054003)(199003)(479174004)(76104003)(24454002)(31696002)(2950100001)(77156002)(62966003)(33646002)(15975445007)(106466001)(86362001)(74316001)(23746002)(50466002)(64126003)(65806001)(47776003)(70736001)(87936001)(83506001)(65956001)(19580395003)(50986999)(1496007)(92566002)(53416004)(46102003)(76176999)(54356999)(65826006);DIR:OUT;SFP:1101;SCL:1;SRVR:BN1AFFO11HUB044;H:xsj-pvapsmtpgw01;FPR:;SPF:Pass;MLV:sfv;MX:1;A:1;LANG:en; X-Microsoft-Antispam: UriScan:;BCL:0;PCL:0;RULEID:;SRVR:BN1AFFO11HUB044; X-Microsoft-Antispam-PRVS: X-Exchange-Antispam-Report-Test: UriScan:; X-Exchange-Antispam-Report-CFA-Test: BCL:0;PCL:0;RULEID:(601004)(5005006)(5002010);SRVR:BN1AFFO11HUB044;BCL:0;PCL:0;RULEID:;SRVR:BN1AFFO11HUB044; X-Forefront-PRVS: 0528942FD8 X-OriginatorOrg: xilinx.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 27 Mar 2015 10:56:02.7754 (UTC) X-MS-Exchange-CrossTenant-Id: 657af505-d5df-48d0-8300-c31994686c5c X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=657af505-d5df-48d0-8300-c31994686c5c;Ip=[149.199.60.83];Helo=[xsj-pvapsmtpgw01] X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: BN1AFFO11HUB044 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Mark, 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/successfully > or something if the hardware designers were feeling particularly inspired). I was checking meaning of num-ss-bits and meaning is Number of slaves (taking explanation from Vivado 2014.4) Range 1-32. http://www.xilinx.com/support/documentation/ip_documentation/axi_spi/v1_02_a/axi_spi_ds742.pdf Table 1 - page 4 Checking through the hw design every pin is connected to device to do chip select. That's why I think that num-cs (based on spi-bus.txt) is the right property. Of course hw guys can use decoder from these bits and we could use binding as is used in cadence spi (is-decoded-cs) > I'm not convinced num-cs ever made any sense. Does it mean that num-cs property used by 11 SPI drivers is just incorrect? 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. Thanks, Michal