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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0E0A2C4332F for ; Fri, 4 Nov 2022 17:01:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231909AbiKDRBA (ORCPT ); Fri, 4 Nov 2022 13:01:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50286 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231361AbiKDRBA (ORCPT ); Fri, 4 Nov 2022 13:01:00 -0400 Received: from vern.gendns.com (vern.gendns.com [98.142.107.122]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 57A0C31FA6; Fri, 4 Nov 2022 10:00:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lechnology.com; s=default; h=Content-Transfer-Encoding:Content-Type: In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date:Message-ID:Sender :Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=4AvnEeQeniDWkQBvG292xKcyqRcJZJN4ObwNBkkj5tk=; b=WdhahLUmGJpQ95hVL+3u1VjMxb tUf7myaQndCk0qHzeKh1A+E2O/JcVf+aJ+IiQD/qFkAbTU535DJ2WAUD6UP1/EvQ/y4beijc5YALa Q3fcMmim22RAxWP0Rh4RhjXR+GqdPYPNBO9KnnRYGmufKc5r2oNWcdiYm05562NzkHszBUsTfAWO7 JgFdZNqyyoguqSiEpMW173KJx1qkCjb5qv/86gVYx+OCVFDAJzuXuMvEgrqYPPENnQENv9FFS7mH/ qsMwcba1c5ad5x6Y1xKSIlEvINxjtsa56wEJ+F6ehiPRzOvf9PnvY6QcDHcSY53EeaOn9zO5Boa6z wQg4vJPQ==; Received: from ip98-183-112-30.ok.ok.cox.net ([98.183.112.30]:58206 helo=[192.168.0.134]) by vern.gendns.com with esmtpsa (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (Exim 4.95) (envelope-from ) id 1oqzog-00Chgx-Is; Fri, 04 Nov 2022 12:45:28 -0400 Message-ID: <187e61cd-7d02-2453-acf1-30180559d42f@lechnology.com> Date: Fri, 4 Nov 2022 11:45:17 -0500 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.2.2 Subject: Re: [PATCH v2 21/65] clk: davinci: da8xx-cfgchip: Add a determine_rate hook Content-Language: en-US To: Maxime Ripard , Stephen Boyd , Maxime Coquelin , Chen-Yu Tsai , Daniel Vetter , Nicolas Ferre , Thierry Reding , Jaroslav Kysela , Shawn Guo , Fabio Estevam , Ulf Hansson , Claudiu Beznea , Michael Turquette , Dinh Nguyen , Paul Cercueil , Chunyan Zhang , Manivannan Sadhasivam , =?UTF-8?Q?Andreas_F=c3=a4rber?= , Jonathan Hunter , Abel Vesa , Charles Keepax , Alessandro Zummo , Peter De Schrijver , Orson Zhai , Alexandre Torgue , Prashant Gaikwad , Liam Girdwood , Alexandre Belloni , Samuel Holland , Matthias Brugger , Richard Fitzgerald , Vinod Koul , NXP Linux Team , Sekhar Nori , Kishon Vijay Abraham I , Linus Walleij , Takashi Iwai , David Airlie , Luca Ceresoli , Jernej Skrabec , Pengutronix Kernel Team , Baolin Wang , Sascha Hauer , Mark Brown , Max Filippov , Geert Uytterhoeven Cc: linux-stm32@st-md-mailman.stormreply.com, alsa-devel@alsa-project.org, linux-mediatek@lists.infradead.org, linux-phy@lists.infradead.org, linux-mips@vger.kernel.org, linux-renesas-soc@vger.kernel.org, linux-actions@lists.infradead.org, linux-clk@vger.kernel.org, AngeloGioacchino Del Regno , patches@opensource.cirrus.com, linux-tegra@vger.kernel.org, linux-rtc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-sunxi@lists.linux.dev, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org References: <20221018-clk-range-checks-fixes-v2-0-f6736dec138e@cerno.tech> <20221018-clk-range-checks-fixes-v2-21-f6736dec138e@cerno.tech> From: David Lechner In-Reply-To: <20221018-clk-range-checks-fixes-v2-21-f6736dec138e@cerno.tech> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - vern.gendns.com X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - lechnology.com X-Get-Message-Sender-Via: vern.gendns.com: authenticated_id: davidmain+lechnology.com/only user confirmed/virtual account not confirmed X-Authenticated-Sender: vern.gendns.com: davidmain@lechnology.com X-Source: X-Source-Args: X-Source-Dir: Precedence: bulk List-ID: X-Mailing-List: linux-tegra@vger.kernel.org On 11/4/22 8:17 AM, Maxime Ripard wrote: > The Davinci DA8xxx cfgchip mux clock implements a mux with a set_parent > hook, but doesn't provide a determine_rate implementation. > > This is a bit odd, since set_parent() is there to, as its name implies, > change the parent of a clock. However, the most likely candidate to > trigger that parent change is a call to clk_set_rate(), with > determine_rate() figuring out which parent is the best suited for a > given rate. > > The other trigger would be a call to clk_set_parent(), but it's far less > used, and it doesn't look like there's any obvious user for that clock. > > So, the set_parent hook is effectively unused, possibly because of an > oversight. However, it could also be an explicit decision by the > original author to avoid any reparenting but through an explicit call to > clk_set_parent(). The parent is defined in the device tree and is not expected to change at runtime, so if I am understanding the patch correctly, setting the CLK_SET_RATE_NO_REPARENT flag seems correct. > > The latter case would be equivalent to setting the flag > CLK_SET_RATE_NO_REPARENT, together with setting our determine_rate hook > to __clk_mux_determine_rate(). Indeed, if no determine_rate > implementation is provided, clk_round_rate() (through > clk_core_round_rate_nolock()) will call itself on the parent if > CLK_SET_RATE_PARENT is set, and will not change the clock rate > otherwise. __clk_mux_determine_rate() has the exact same behavior when > CLK_SET_RATE_NO_REPARENT is set. > > And if it was an oversight, then we are at least explicit about our > behavior now and it can be further refined down the line. > > Signed-off-by: Maxime Ripard > --- > drivers/clk/davinci/da8xx-cfgchip.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/clk/davinci/da8xx-cfgchip.c b/drivers/clk/davinci/da8xx-cfgchip.c > index 4103d605e804..c04276bc4051 100644 > --- a/drivers/clk/davinci/da8xx-cfgchip.c > +++ b/drivers/clk/davinci/da8xx-cfgchip.c > @@ -229,6 +229,7 @@ static u8 da8xx_cfgchip_mux_clk_get_parent(struct clk_hw *hw) > } > > static const struct clk_ops da8xx_cfgchip_mux_clk_ops = { > + .determine_rate = __clk_mux_determine_rate, > .set_parent = da8xx_cfgchip_mux_clk_set_parent, > .get_parent = da8xx_cfgchip_mux_clk_get_parent, > }; > @@ -251,7 +252,7 @@ da8xx_cfgchip_mux_clk_register(struct device *dev, > init.ops = &da8xx_cfgchip_mux_clk_ops; > init.parent_names = parent_names; > init.num_parents = 2; > - init.flags = 0; > + init.flags = CLK_SET_RATE_NO_REPARENT; > > mux->hw.init = &init; > mux->regmap = regmap; >