From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751514AbeFBGkl (ORCPT ); Sat, 2 Jun 2018 02:40:41 -0400 Received: from mail.kernel.org ([198.145.29.99]:54184 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750812AbeFBGkh (ORCPT ); Sat, 2 Jun 2018 02:40:37 -0400 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 To: Rajan Vaja From: Stephen Boyd In-Reply-To: Cc: "linux-clk@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Jolly Shah , Michal Simek , "mturquette@baylibre.com" References: <1520518500-5500-1-git-send-email-rajanv@xilinx.com> <152061989141.26240.15533446439693285034@swboyd.mtv.corp.google.com> <152113963269.111154.10395846178696174140@swboyd.mtv.corp.google.com> Message-ID: <152792163637.225090.8916381060805852261@swboyd.mtv.corp.google.com> User-Agent: alot/0.7 Subject: RE: [PATCH] clk: clk-fixed-factor: Use new macro CLK_OF_DECLARE_DRIVER Date: Fri, 01 Jun 2018 23:40:36 -0700 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by mail.home.local id w526eki2004105 Quoting Rajan Vaja (2018-05-03 02:18:30) > Hi Stephen, > > > -----Original Message----- > > From: Rajan Vaja > > Sent: 16 March 2018 05:20 PM > > To: 'Stephen Boyd' > > Cc: linux-clk@vger.kernel.org; linux-kernel@vger.kernel.org; Jolly Shah > > ; Michal Simek ; > > mturquette@baylibre.com > > Subject: RE: [PATCH] clk: clk-fixed-factor: Use new macro > > CLK_OF_DECLARE_DRIVER > > > > Hi Stephen, > > > > Thanks for the comment. > > > > > -----Original Message----- > > > From: Stephen Boyd [mailto:sboyd@kernel.org] > > > Sent: 16 March 2018 12:17 AM > > > To: Rajan Vaja > > > Cc: linux-clk@vger.kernel.org; linux-kernel@vger.kernel.org; Jolly Shah > > > ; Michal Simek ; > > > mturquette@baylibre.com > > > Subject: RE: [PATCH] clk: clk-fixed-factor: Use new macro > > > CLK_OF_DECLARE_DRIVER > > > > > > Quoting Rajan Vaja (2018-03-09 11:27:40) > > > > > From: Stephen Boyd [mailto:sboyd@kernel.org] > > > > > > > > > > Is the intent to register the clk twice? I believe things are working as > > > > > intended without this patch, so maybe you can explain a little more what > > > > > you're trying to fix. > > > > [Rajan] Yes. During of_clk_init() if some DT fixed factor clock has > > > > parent which is neither mentioned in output-clock-names of clock > > > > controller nor registered as clock provider, of_clk_init() will try to > > > > forcefully register in second loop. > > > > > > > > if (force || parent_ready(clk_provider->np)) { > > > > > > > > /* Don't populate platform devices */ > > > > of_node_set_flag(clk_provider->np, > > > > OF_POPULATED); > > > > > > > > So registration of this DT fixed-factor clock would fail as parent > > > > would be NULL as below (called from _of_fixed_factor_clk_setup()): > > > > parent_name = of_clk_get_parent_name(node, 0); > > > > > > > > On the other hand, even if registration failed, that node will be > > > > marked as OF_POPULATED, so probe of clk-fixed-factor.c will also not > > > > be called and that DT fixed-factor clock would never be registered. > > > > > > > > Same thing is discussed at https://lkml.org/lkml/2017/6/5/681 . > > > > > > Ok. I believe the answer is to fix the DT to describe the parent chain > > > properly with clock-output-names. Otherwise, we have no good way of > > > figuring out what the name should be. > > [Rajan] clock DT binding doc says that clock-output-names property > > is optional and sometimes not recommended. > > I think this patch fixes the issue we have which mandates to add clock-output- > > names > > property (for this particular case). Also, IIUC platform driver probe in clk-fixed- > > factor.c > > will never be called unless we use CLK_OF_DECLARE_DRIVER. > > I completely agree that proper solution would be to stop using strings to > > describe clock topology. > [Rajan] Any comments on this? > Unless we have proper solution ready, we need to have some mechanism to handle this scenario. > clock-output-names is optional and without this, it mandates to use clock-output-names. > I couldn't read your outlook sent email and I was too busy to go translate it. Some bug in my MUA it seems. Can you add the output-names property? In this case it's practically mandatory, so if you can't do it I'd like to hear why not.