From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lars-Peter Clausen Subject: Re: Driver for daisy-chained AD1938 audio codecs? Date: Wed, 12 Oct 2011 11:13:24 +0200 Message-ID: <4E955A34.3020608@metafoo.de> References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from smtp-out-103.synserver.de (smtp-out-126.synserver.de [212.40.185.126]) by alsa0.perex.cz (Postfix) with SMTP id 0CDC2103921 for ; Wed, 12 Oct 2011 11:13:26 +0200 (CEST) In-Reply-To: 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: steve.strobel@link-comm.com Cc: alsa-devel@alsa-project.org, Steve Strobel List-Id: alsa-devel@alsa-project.org On 10/11/2011 06:04 PM, Steve Strobel wrote: > I am considering a Blackfin DSP hardware design which would need eight > channels of audio input/output. I haven't been able to find a single > audio codec with more than six input channels, so I am looking at > daisy-chaining AD1938 codecs as described on page 19 of its datasheet > [1]. > > In the past I worked on a prototype that used two AD1938 chips on > separate SPORT interfaces. It worked, but having to deal with two ALSA > sound devices made the software relatively complicated (error > recovery, synchronization, etc). It would be nice if all of the > channels appeared as a single ALSA device. I believe that > daisy-chained AD1938 chips would work that way, but I haven't found an > ALSA driver for that configuration. > Does such a driver already exist? Any suggestions for making one? > Thanks for any input. > Steve > [1] - http://www.analog.com/static/imported-files/data_sheets/AD1938.pdf Hi, the existing driver should work fine, at least for daisy-chained ADCs. Just setup the number of TDM slots using snd_soc_dai_set_tdm_slot. You'll need to register one of the codecs as primary codec and the other as an auxdev in your snd_soc_card structure. - Lars