From mboxrd@z Thu Jan 1 00:00:00 1970 From: Liam Girdwood Subject: Re: [ASoc] TDM over one SSC channel on AT91 possible? Date: Fri, 09 Nov 2007 12:54:29 +0000 Message-ID: <1194612869.3180.412.camel@localhost.localdomain> References: <4734465C.4020900@scottygroup.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from opensource.wolfsonmicro.com (unknown [80.75.67.54]) by alsa0.perex.cz (Postfix) with ESMTP id 6946D243D2 for ; Fri, 9 Nov 2007 13:54:30 +0100 (CET) Received: from [10.0.2.101] (lrg2.demon.co.uk [80.176.148.77]) (using SSLv3 with cipher RC4-MD5 (128/128 bits)) (No client certificate requested) by opensource.wolfsonmicro.com (Postfix) with ESMTP id AE261D805C for ; Fri, 9 Nov 2007 11:52:02 +0000 (GMT) In-Reply-To: <4734465C.4020900@scottygroup.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: Alsa-Devel Mailing List List-Id: alsa-devel@alsa-project.org On Fri, 2007-11-09 at 12:37 +0100, Friedrich Lobenstock wrote: > Hello! > > The background: I'm just designing an ATMEL AT91RM9200 based board which > got two TLV320AIC33 on board. It is either possible > to hook up the two TLV320AIC33 to a separate SSC (synchronous serial > control) channel each or use one SSC channel and configure it for TDM (time > division multiplex) mode. There is already a driver for > TLV320AIC14k/TLV320AIC2k in the development tree, so adding support for the > TLV320AIC33 should be feasible. > Fwiw, TDM will save you a SSC port but will make similtanious use of both codecs at different rates/formats difficult. It depends on your use cases. > What I'm not sure about is the fact if ASOC is prepared for using channels, > especially SSC, in TDM mode. Is the core ASOC structure prepared to handle > that? It is for some platforms, but I think AT91 SSC and your codec will need set_tdm_slot() implemented. Your machine driver will call set_tdm_slot to configure codec/SSC slots. > > Would we be better off instantiate one drive twice each time with different > parameters for the SSC channel? > I would instantiate one driver with 3 pcms. This would allow:- pcm0: 2 channel, slot 0,1 pcm1: 2 channel, slot 2,3 pcm2: 4 channel, slot 0,1,2,3 Giving full flexibility for many use cases. The pcms would be mutually exclusive (enforced by machine driver). HTH Liam