From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754819Ab3LaRpb (ORCPT ); Tue, 31 Dec 2013 12:45:31 -0500 Received: from smtp4-g21.free.fr ([212.27.42.4]:40584 "EHLO smtp4-g21.free.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753897Ab3LaRpa convert rfc822-to-8bit (ORCPT ); Tue, 31 Dec 2013 12:45:30 -0500 Date: Tue, 31 Dec 2013 18:44:30 +0100 From: Jean-Francois Moine To: Mark Brown Cc: Liam Girdwood , Jaroslav Kysela , Takashi Iwai , alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] ASoC: make snd_soc_dai_link more symmetrical Message-ID: <20131231184430.3a4c9414@armhf> In-Reply-To: <20131231165533.GK31886@sirena.org.uk> References: <20131212185917.7ed6b21f@armhf> <20131231165533.GK31886@sirena.org.uk> X-Mailer: Claws Mail 3.9.3 (GTK+ 2.24.22; arm-unknown-linux-gnueabihf) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 31 Dec 2013 16:55:33 +0000 Mark Brown wrote: > On Thu, Dec 12, 2013 at 06:59:17PM +0100, Jean-Francois Moine wrote: > > > This patch renders optional the CODEC name / OF node on sound card register, > > as it is done for the CPU side, in the case the CODEC DAI name is unique. > > > This simplifies the definition of CODECs with multiple DAIs, especially > > in DTs, while keeping compatibility. > > So, this is similar to one of the comments I made on the DT patch you > sent today: you're saying that this makes things better but you're not > saying why it makes things better. I've been sitting on this partly > because I've been wanting to sit down and try to work out what the > benefit is. This information should be readily avaiable and omiting it > seems like it will make things more fragile. > > If anything I'd expect DT to want to move towards specifying things by > CODEC plus optional DAI index rather than anything else, that's the more > common pattern for DT based things (really phandle plus index) and it's > what the current generic card is doing. > > It's possible there is a benefit I'm just not seeing but you'll need to > tell me. The first benefit I got was in the front-end definition: the codec side is the dummy codec, and this one has no phandle. Then, finding the CODEC DAI from phandle asks for more code (of_xlate_dai_name in the CODEC drivers) and finding it from the CODEC name asks for a double loop in soc_bind_dai_link. On the other way, a simple loop without any more change may be used when the DAI is simply specified by its name. I would say that the DAI name is more meaningful than a DAI index and that it is less subject to internal changes of the CODEC driver. Eventually, I don't think that, using only the name of the CODEC side DAI to identify it, is not more fragile than identifying the CPU side of the DAI link by its name. -- Ken ar c'hentañ | ** Breizh ha Linux atav! ** Jef | http://moinejf.free.fr/