From mboxrd@z Thu Jan 1 00:00:00 1970 From: Liam Girdwood Subject: Re: FW: [PATCH v3] ASoC: Add support for TI LM49453 Audio codec Date: Wed, 08 Feb 2012 13:27:30 +0000 Message-ID: <1328707650.3955.17.camel@odin> References: <290463D19D2E064191F1F96ECA480A89434AC4A96E@EXMAIL02.scwf.nsc.com> <4F323BF5.4010309@ti.com> <1328692723.3955.4.camel@odin> <1328693854.21099.5.camel@vkoul-udesk3> <1328694877.3955.9.camel@odin> <1328697415.21099.8.camel@vkoul-udesk3> <1328698650.3955.13.camel@odin> <20120208112059.GB3120@opensource.wolfsonmicro.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from na3sys009aog120.obsmtp.com (na3sys009aog120.obsmtp.com [74.125.149.140]) by alsa0.perex.cz (Postfix) with ESMTP id A6FAB2440E for ; Wed, 8 Feb 2012 14:27:34 +0100 (CET) Received: by mail-ww0-f45.google.com with SMTP id dt12so490646wgb.14 for ; Wed, 08 Feb 2012 05:27:32 -0800 (PST) In-Reply-To: <20120208112059.GB3120@opensource.wolfsonmicro.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: alsa-devel-bounces@alsa-project.org Errors-To: alsa-devel-bounces@alsa-project.org To: Mark Brown Cc: Vinod Koul , M R Swami Reddy , "alsa-devel@alsa-project.org" List-Id: alsa-devel@alsa-project.org On Wed, 2012-02-08 at 11:20 +0000, Mark Brown wrote: > On Wed, Feb 08, 2012 at 10:57:30AM +0000, Liam Girdwood wrote: > > On Wed, 2012-02-08 at 16:06 +0530, Vinod Koul wrote: > > > > We want to dynamical turn off this clock when not is use and turn on > > > only when codec is using. So I was thinking of turning this ON in > > > codecs .set_bias_level callback, but how to propagate this into machine > > > driver? > > > It's usually done in the machine driver hw_params() since at this point > > we know the rate, format etc that can have a bearing on the clock > > configuration. You could switch it OFF in machine hw_free(). > > For modern devices set_bias_level() is often a better choice if you're > only going to do one of that or hw_params(), especially on the shutdown > paths - devices these days typically need the clocks for a lot more > stuff. hw_params() by itself obviously has issues for analogue only > paths too. > I'd generally expect to see new machine drivers doing this stuff in > set_bias_level() and possibly also having additional startup code in > hw_params() depending on how flexible the clocking is. The scope of set_bias_level() is now starting to increase to more than just the card bias power. It may be worthwhile at some point to rename it to cover all possibilities. Liam