Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755962AbbLWLsK (ORCPT ); Wed, 23 Dec 2015 06:48:10 -0500 Received: from mail-bl2nam02on0067.outbound.protection.outlook.com ([104.47.38.67]:33568 "EHLO NAM02-BL2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755699AbbLWLsI (ORCPT ); Wed, 23 Dec 2015 06:48:08 -0500 Authentication-Results: spf=pass (sender IP is 149.199.60.83) smtp.mailfrom=xilinx.com; vger.kernel.org; dkim=none (message not signed) header.d=none;vger.kernel.org; dmarc=bestguesspass action=none header.from=xilinx.com; Date: Wed, 23 Dec 2015 03:49:08 -0800 From: =?utf-8?B?U8O2cmVu?= Brinkmann To: Ranjit Waghmode CC: , , , , , , , , , , , , Subject: Re: [RFC LINUX PATCH] dt: xilinx: xadc: provision to control clock frequency Message-ID: <20151223114908.GG6491@xsjsorenbubuntu> References: <1450866505-22069-1-git-send-email-ranjit.waghmode@xilinx.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1450866505-22069-1-git-send-email-ranjit.waghmode@xilinx.com> User-Agent: Mutt/1.5.23 (2014-03-12) X-RCIS-Action: ALLOW X-TM-AS-Product-Ver: IMSS-7.1.0.1224-8.0.0.1202-22018.006 X-TM-AS-User-Approved-Sender: Yes;Yes X-EOPAttributedMessage: 0 X-Forefront-Antispam-Report: CIP:149.199.60.83;CTRY:US;IPV:NLI;EFV:NLI;SFV:NSPM;SFS:(10009020)(6009001)(2980300002)(438002)(24454002)(164054003)(189002)(199003)(377424004)(4001450100002)(110136002)(81156007)(33716001)(57986006)(54356999)(85202003)(1220700001)(4001430100002)(87936001)(107886002)(92566002)(4001350100001)(1076002)(2950100001)(189998001)(11100500001)(1096002)(47776003)(36386004)(76176999)(63266004)(50466002)(586003)(5001960100002)(85182001)(106466001)(83506001)(6806005)(76506005)(23676002)(77096005)(86362001)(5008740100001)(50986999)(33656002)(4001150100001)(107986001)(217873001);DIR:OUT;SFP:1101;SCL:1;SRVR:SN1NAM02HT021;H:xsj-pvapsmtpgw01;FPR:;SPF:Pass;PTR:unknown-60-83.xilinx.com;MX:1;A:1;LANG:en; X-Microsoft-Antispam: UriScan:;BCL:0;PCL:0;RULEID:(8251501001);SRVR:SN1NAM02HT021; X-Microsoft-Antispam-PRVS: <73206b192dd94de8932feb16d7e320dc@SN1NAM02HT021.eop-nam02.prod.protection.outlook.com> X-Exchange-Antispam-Report-Test: UriScan:; X-Exchange-Antispam-Report-CFA-Test: BCL:0;PCL:0;RULEID:(601004)(2401047)(520078)(5005006)(8121501046)(10201501046)(3002001);SRVR:SN1NAM02HT021;BCL:0;PCL:0;RULEID:;SRVR:SN1NAM02HT021; X-Forefront-PRVS: 0799B1B2D7 X-OriginatorOrg: xilinx.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 23 Dec 2015 11:48:04.8217 (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: SN1NAM02HT021 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1027 Lines: 28 On Wed, 2015-12-23 at 03:58PM +0530, Ranjit Waghmode wrote: > This patch adds parameter to the xilinx-xadc node for controlling > clock frequency. > > Following are the possible options for user to control the frequency: > * 00 : 1/2 of clock frequency > * 01 : 1/4 of clock frequency > * 10 : 1/8 of clock frequency > * 11 : 1/16 of clock frequency How is this chosen? Are these just arbitrary values that you need for some use-case? Or are these the options HW allows? > > So this patch adds parameter tck-rate to set user defined values from > above pool to control the clock frequency. This is no longer describing HW, but configuring driver/HW. Why does this have to be in DT? Why can't the driver request/set the frequency as operation requires it? Thanks, Sören -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/