From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.7 required=3.0 tests=BAYES_00,DKIM_ADSP_CUSTOM_MED, FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AAAF4C6377D for ; Thu, 22 Jul 2021 15:42:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 830CF610D2 for ; Thu, 22 Jul 2021 15:42:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232200AbhGVPBt (ORCPT ); Thu, 22 Jul 2021 11:01:49 -0400 Received: from mga06.intel.com ([134.134.136.31]:59349 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230343AbhGVPBt (ORCPT ); Thu, 22 Jul 2021 11:01:49 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10053"; a="272788297" X-IronPort-AV: E=Sophos;i="5.84,261,1620716400"; d="scan'208";a="272788297" Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Jul 2021 08:42:22 -0700 X-IronPort-AV: E=Sophos;i="5.84,261,1620716400"; d="scan'208";a="433170406" Received: from smile.fi.intel.com (HELO smile) ([10.237.68.40]) by fmsmga007-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Jul 2021 08:42:20 -0700 Received: from andy by smile with local (Exim 4.94.2) (envelope-from ) id 1m6apx-00H1rQ-GS; Thu, 22 Jul 2021 18:42:13 +0300 Date: Thu, 22 Jul 2021 18:42:13 +0300 From: Andy Shevchenko To: Liu Ying Cc: Heiko Stuebner , Elaine Zhang , Stephen Boyd , linux-kernel@vger.kernel.org, linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org, Michael Turquette , NXP Linux Team , Jacky Bai Subject: Re: [PATCH v2 2/3] clk: fractional-divider: Introduce NO_PRESCALER flag Message-ID: References: <20210716133448.24890-1-andriy.shevchenko@linux.intel.com> <20210716133448.24890-2-andriy.shevchenko@linux.intel.com> <9117e5212a3b743ca541918ec2b701c159ac752c.camel@nxp.com> <08ca856c013aba60e686f050e06a6e3179de6030.camel@nxp.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <08ca856c013aba60e686f050e06a6e3179de6030.camel@nxp.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo Precedence: bulk List-ID: X-Mailing-List: linux-clk@vger.kernel.org On Thu, Jul 22, 2021 at 05:43:49PM +0800, Liu Ying wrote: > On Thu, 2021-07-22 at 12:38 +0300, Andy Shevchenko wrote: > > On Thu, Jul 22, 2021 at 12:33 PM Liu Ying wrote: > > > On Fri, 2021-07-16 at 16:34 +0300, Andy Shevchenko wrote: > > > > The newly introduced flag, when set, makes the flow to skip > > > > the assumption that the caller will use an additional 2^scale > > > > prescaler to get the desired clock rate. > > > > > > As I mentioned in v1 comment, it seems to be good to decouple the > > > prescaler knowledge from this common fractional divider clk driver. > > > This way, we'll make it simpler and easier to maintain. Also, then, the > > > NO_PRESCALER flag is not needed at all. However, it seems that two > > > Intel drivers which use the frational divider drivers will be affected > > > and rate negotiation logics need to be implemented for them. Please > > > consider if it's doable or not. > > > > The current driver works for the certain hardware without this change. > > If you think it's better, submit a proposal we will discuss. > > Well, I'm not afford to do so. Just share an idea. I haven't got the > intel HW to test. As I mentioned in v1 comment, it seems that you have > experience on relevent drivers and HW to test, may I encourage you to > do that :-) Or forget that if you really think you won't do that. Noted. I am in support of this idea, and will help with testing on Intel HW if anyone submits the code. > > > If we ultimately keep the prescaler knowledge here, please consider to > > > add the NO_PRESCALER flag for i.MX7ulp as it hasn't the prescaler IIUC. > > > > You mean there is a code which is currently using this driver w/o > > taking into account this prescaller flavour? Can you, please, point > > out, I'll definitely update it. Thanks for the catch! > > drivers/clk/imx/clk-composite-7ulp.c Thanks, I'll update in v3. Can you, please, look the other patch(es)? -- With Best Regards, Andy Shevchenko