From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754673AbaCSTPe (ORCPT ); Wed, 19 Mar 2014 15:15:34 -0400 Received: from devils.ext.ti.com ([198.47.26.153]:35773 "EHLO devils.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753818AbaCSTPa (ORCPT ); Wed, 19 Mar 2014 15:15:30 -0400 Message-ID: <5329ECC2.7040803@ti.com> Date: Wed, 19 Mar 2014 21:15:14 +0200 From: Jyri Sarha User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.3.0 MIME-Version: 1.0 To: Lars-Peter Clausen CC: Jean-Francois Moine , Mark Brown , , , Xiubo Li , , Kuninori Morimoto Subject: Re: [alsa-devel] [PATCH v3 4/4] ASoC: simple-card: Add DT documentation for multi-DAI links References: <20140317164339.GR11706@sirena.org.uk> <20140318091728.1d2240ca@armhf> <53296CB7.1000909@ti.com> <5329E749.6070900@metafoo.de> In-Reply-To: <5329E749.6070900@metafoo.de> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/19/2014 08:51 PM, Lars-Peter Clausen wrote: > On 03/19/2014 11:08 AM, Jyri Sarha wrote: > [...] >> It may sometimes be helpful to allow overwriting link level settings >> in dai >> level. In order to do that it should be possible to write all daifmt >> settings explicitly like this: >> >> bitclock-inversion = <0>; /* <0> = no bitclock-inversion */ > > When does this make sense? Either the bitclock is inverted for all of > them or for none. > Definition of clock signal and it's inversion varies between chip manufacturers and sometimes it may not be possible to get all the dai drivers to work identically in this respect. Because of this in some cases there may be a need to set the inversion bit only at one end of the link. I think there was an example of this in some mail regarding the simple-card DT-bidings, but I can't find it ATM. Best regards, Jyri