Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966137AbbBCQxx (ORCPT ); Tue, 3 Feb 2015 11:53:53 -0500 Received: from smtp-out-020.synserver.de ([212.40.185.20]:1054 "EHLO smtp-out-017.synserver.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755875AbbBCQxv (ORCPT ); Tue, 3 Feb 2015 11:53:51 -0500 X-SynServer-TrustedSrc: 1 X-SynServer-AuthUser: lars@metafoo.de X-SynServer-PPID: 29436 Message-ID: <54D0FD1C.9020305@metafoo.de> Date: Tue, 03 Feb 2015 17:53:48 +0100 From: Lars-Peter Clausen User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Icedove/31.4.0 MIME-Version: 1.0 To: Mark Brown , Manuel Lauss CC: alsa-devel , Richard Purdie , patches@opensource.wolfsonmicro.com, LKML , linux-sound@vger.kernel.org, Manuel Lauss , Bo Shen , linux-arm-kernel@lists.infradead.org, Liam Girdwood Subject: Re: [alsa-devel] [RFC PATCH] ASoC: wm8731: let codec to manage clock by itself References: <1422934415-24957-1-git-send-email-voice.shen@atmel.com> <20150203124441.GK21293@sirena.org.uk> In-Reply-To: <20150203124441.GK21293@sirena.org.uk> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1142 Lines: 25 On 02/03/2015 01:44 PM, Mark Brown wrote: > On Tue, Feb 03, 2015 at 08:54:57AM +0100, Manuel Lauss wrote: > >> + wm8731->mclk = devm_clk_get(&spi->dev, "mclk"); >> + if (IS_ERR(wm8731->mclk)) { >> + wm8731->mclk = NULL; >> + dev_warn(&spi->dev, "assuming static MCLK\n"); >> + } > > This is broken for both deferred probe and in the case where the clock > API genuinely returns a NULL clock. Other than that it's the kind of > thing that we've done for some other drivers, though it's not good to > have to do this. Check them for correct behaviour. Ideally we'd introduce a {devm_}clk_get_optional(), with the same semantics as gpiod_get_optional(), which handles the finer details of differentiating between clock specified, but not yet probed, clock specified, but incorrectly and no clock specified, so this doesn't have to be done over and over by each driver. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/