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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 B047AC433E0 for ; Fri, 26 Jun 2020 21:04:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8B1222070A for ; Fri, 26 Jun 2020 21:04:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725803AbgFZVEA (ORCPT ); Fri, 26 Jun 2020 17:04:00 -0400 Received: from relay9-d.mail.gandi.net ([217.70.183.199]:40659 "EHLO relay9-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725781AbgFZVEA (ORCPT ); Fri, 26 Jun 2020 17:04:00 -0400 X-Originating-IP: 86.202.110.81 Received: from localhost (lfbn-lyo-1-15-81.w86-202.abo.wanadoo.fr [86.202.110.81]) (Authenticated sender: alexandre.belloni@bootlin.com) by relay9-d.mail.gandi.net (Postfix) with ESMTPSA id 4CC30FF804; Fri, 26 Jun 2020 21:03:57 +0000 (UTC) Date: Fri, 26 Jun 2020 23:03:57 +0200 From: Alexandre Belloni To: Claudiu Beznea Cc: mturquette@baylibre.com, sboyd@kernel.org, nicolas.ferre@microchip.com, ludovic.desroches@microchip.com, linux-kernel@vger.kernel.org, mturquette@linaro.org, bbrezillon@kernel.org, linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH 2/2] clk: at91: main: do not continue if oscillators already prepared Message-ID: <20200626210357.GX131826@piout.net> References: <1593079768-9349-1-git-send-email-claudiu.beznea@microchip.com> <1593079768-9349-2-git-send-email-claudiu.beznea@microchip.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1593079768-9349-2-git-send-email-claudiu.beznea@microchip.com> Sender: linux-clk-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-clk@vger.kernel.org On 25/06/2020 13:09:28+0300, Claudiu Beznea wrote: > Return in clk_main_osc_prepare()/clk_main_rc_osc_prepare() if > oscillators are already enabled. > > Fixes: 27cb1c2083373 ("clk: at91: rework main clk implementation") > Fixes: 1bdf02326b71e ("clk: at91: make use of syscon/regmap internally") Is this really a fix? What is the observed issue? > Signed-off-by: Claudiu Beznea > --- > drivers/clk/at91/clk-main.c | 18 +++++++++--------- > 1 file changed, 9 insertions(+), 9 deletions(-) > > diff --git a/drivers/clk/at91/clk-main.c b/drivers/clk/at91/clk-main.c > index 37c22667e831..46b4d2131989 100644 > --- a/drivers/clk/at91/clk-main.c > +++ b/drivers/clk/at91/clk-main.c > @@ -74,13 +74,11 @@ static int clk_main_osc_prepare(struct clk_hw *hw) > regmap_read(regmap, AT91_CKGR_MOR, &tmp); > tmp &= ~MOR_KEY_MASK; > > - if (tmp & AT91_PMC_OSCBYPASS) > + if (tmp & (AT91_PMC_OSCBYPASS | AT91_PMC_MOSCEN)) > return 0; While this seems like a good optimization, it is also not correct. Having AT91_PMC_MOSCEN set doesn't mean that the clock is ready, you need to at least check MOSCS once. > > - if (!(tmp & AT91_PMC_MOSCEN)) { > - tmp |= AT91_PMC_MOSCEN | AT91_PMC_KEY; > - regmap_write(regmap, AT91_CKGR_MOR, tmp); > - } > + tmp |= AT91_PMC_MOSCEN | AT91_PMC_KEY; > + regmap_write(regmap, AT91_CKGR_MOR, tmp); > > while (!clk_main_osc_ready(regmap)) > cpu_relax(); > @@ -186,10 +184,12 @@ static int clk_main_rc_osc_prepare(struct clk_hw *hw) > > regmap_read(regmap, AT91_CKGR_MOR, &mor); > > - if (!(mor & AT91_PMC_MOSCRCEN)) > - regmap_update_bits(regmap, AT91_CKGR_MOR, > - MOR_KEY_MASK | AT91_PMC_MOSCRCEN, > - AT91_PMC_MOSCRCEN | AT91_PMC_KEY); > + if (mor & AT91_PMC_MOSCRCEN) > + return 0; > + > + regmap_update_bits(regmap, AT91_CKGR_MOR, > + MOR_KEY_MASK | AT91_PMC_MOSCRCEN, > + AT91_PMC_MOSCRCEN | AT91_PMC_KEY); > > while (!clk_main_rc_osc_ready(regmap)) > cpu_relax(); > -- > 2.7.4 > -- Alexandre Belloni, Bootlin Embedded Linux and Kernel engineering https://bootlin.com