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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DD2A1C433F5 for ; Wed, 6 Oct 2021 16:38:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BF6BA610E5 for ; Wed, 6 Oct 2021 16:38:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231755AbhJFQkL (ORCPT ); Wed, 6 Oct 2021 12:40:11 -0400 Received: from mga03.intel.com ([134.134.136.65]:9887 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229548AbhJFQkI (ORCPT ); Wed, 6 Oct 2021 12:40:08 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10129"; a="225987827" X-IronPort-AV: E=Sophos;i="5.85,352,1624345200"; d="scan'208";a="225987827" Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Oct 2021 09:37:28 -0700 X-IronPort-AV: E=Sophos;i="5.85,352,1624345200"; d="scan'208";a="439181042" Received: from nbasa-mobl2.amr.corp.intel.com (HELO [10.213.170.135]) ([10.213.170.135]) by orsmga006-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Oct 2021 09:37:27 -0700 Subject: Re: [PATCH v1 3/4] ASoC: Intel: bytcr_rt5651: use devm_clk_get_optional() for mclk To: Andy Shevchenko , Hans de Goede Cc: Mark Brown , alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org, Cezary Rojewski , Liam Girdwood , Jie Yang , Jaroslav Kysela , Takashi Iwai References: <20211006150451.16561-1-andriy.shevchenko@linux.intel.com> <20211006150451.16561-3-andriy.shevchenko@linux.intel.com> <2d190513-7ac4-731c-7c9a-1f60a98f6345@linux.intel.com> From: Pierre-Louis Bossart Message-ID: <015e084e-70ed-7b5c-b103-8426ef0842d4@linux.intel.com> Date: Wed, 6 Oct 2021 11:37:24 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Firefox/78.0 Thunderbird/78.13.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/6/21 11:23 AM, Andy Shevchenko wrote: > On Wed, Oct 06, 2021 at 10:51:52AM -0500, Pierre-Louis Bossart wrote: >> On 10/6/21 10:04 AM, Andy Shevchenko wrote: >>> The devm_clk_get_optional() helper returns NULL when devm_clk_get() >>> returns -ENOENT. This makes things slightly cleaner. The added benefit >>> is mostly cosmetic. > > ... > >>> if (SND_SOC_DAPM_EVENT_ON(event)) { >>> - if (byt_rt5651_quirk & BYT_RT5651_MCLK_EN) { >>> - ret = clk_prepare_enable(priv->mclk); >>> - if (ret < 0) { >>> - dev_err(card->dev, >>> - "could not configure MCLK state"); >>> - return ret; >>> - } >>> + ret = clk_prepare_enable(priv->mclk); >>> + if (ret < 0) { >>> + dev_err(card->dev, "could not configure MCLK state"); >>> + return ret; >>> } >> >> I don't get why you removed the test on the BYT_RT5651_MCLK_EN quirk, >> see below it was designed as a fall-back mode. We don't want to return >> an error when we know the clock is not present/desired. > > Why should we do a unneeded test? When we switch to the optional, there > will be no error from these CCF APIs. Besides that it drops indentation > level and makes code neat. By looking at this code only one cannot really visualize that it's a no-op. I personally prefer to see explicit intent rather than have to dig hundreds of lines below what this clock is optional. I am also not even sure that in real products this clock is actually optional, the default is to make use of it: #define BYT_RT5651_DEFAULT_QUIRKS (BYT_RT5651_MCLK_EN | \ and the only platform without this clock is "Minnowboard Max B3" - probably not used by anyone. I fried mine a long time ago. We'd need to Hans to comment on this since he's really the only one maintaining this code. > ... > >> same here, why was the quirk removed? > > Same answer. > > ... > >> that part in the probe looks fine, but the changes above are controversial. > > I didn't get. How controversial? Why? The whole point of _optional is to get > rid of unneeded checks (since they are _anyway_ be called). It's inconsistent since you kept the following part but no longer use it: + /* + * Fall back to bit clock usage when clock is not + * available likely due to missing dependencies. + */ + if (!priv->mclk) + byt_rt5651_quirk &= ~BYT_RT5651_MCLK_EN;