From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnaud Pouliquen Subject: Re: [RFC] question regarding codec DAI ops Date: Tue, 1 Jul 2014 11:28:44 +0200 Message-ID: <53B27F4C.9040900@st.com> References: <53A44007.1000008@st.com> <20140621102644.GQ5099@sirena.org.uk> <53A7D78B.1050508@st.com> <20140630103127.GX23300@sirena.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: Received: from mx07-00178001.pphosted.com (mx07-00178001.pphosted.com [62.209.51.94]) by alsa0.perex.cz (Postfix) with ESMTP id B416226577B for ; Tue, 1 Jul 2014 11:29:06 +0200 (CEST) In-Reply-To: <20140630103127.GX23300@sirena.org.uk> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: alsa-devel-bounces@alsa-project.org To: Mark Brown Cc: alsa-devel@alsa-project.org, lgirdwood@gmail.com List-Id: alsa-devel@alsa-project.org On 06/30/2014 12:31 PM, Mark Brown wrote: > On Mon, Jun 23, 2014 at 09:30:19AM +0200, Arnaud Pouliquen wrote: >> On 06/21/2014 12:26 PM, Mark Brown wrote: >>> On Fri, Jun 20, 2014 at 04:07:03PM +0200, Arnaud Pouliquen wrote: >>>> I have a platform with several audio IOs (DAC , HDMI...) and I2S In/out >>>> connectors. >>>> I'm using my codec driver but for this I2S output i used dummy codec driver >>>> with the snd-soc-dummy-dai dai. >>> Why are you using the dummy driver? This is intended to stub things out >>> in some DPCM situations rather than as something that should be used in >>> normal code. >> My platform is a base for several projects and customers. In this context >> some extra I2S bus are available for extensions. >> I have two use cases to support. >> - Possibility to test I2S bus without audio codec associated. >> - Support client that does not use ASOC for audio codec ( a.e one manage >> HDMI in his display driver...) >> To be able to support these use cases i use device tree to construct the >> alsa card. if no asoc codec present, i connect dummy one. > No, this is is not at all sensible - don't do that. Think about it for > a minute - if this were something we wanted to do it's going to apply > just as much to any other I2S controller so we should be doing it in the > core. In fact what i really need is a dummy codec driver. But, perhaps, may i the only one to see advantages of using a dummy codec. if it is the case i will implement a dummy DAI in my codec driver. Otherwise tell me if you are interested in a generic dummy codec drivers. > If the user really wants to look at the signals with a scope they > are probably capable of providing a suitable driver for their purposes. Unfortunately, my experience tells me otherwise. > >> If customer want to use another codec they have just to change device tree. >> Here is an example of my device tree declaration. >> sound { >> compatible = "st,snd-soc-sti"; >> st,card-name = "audio"; >> st,audio-routing = >> /* Analog out route */ >> "Analog out","DAC", >> "DAC","dac_p"; >> >> st,asoc-platform = <&sti_asoc_platform>; >> backend-name = "HDMI_out", "PCM_out", >> "Analog_out", "spdif", >> "HDMI_in", "PCM_in"; >> backend-cpu-dai = <&snd_uni_player0 &snd_uni_player1 >> &snd_uni_player2 &snd_uni_player3 >> &snd_uni_reader0 &snd_uni_reader1 >; >> backend-codec = <&sti_sasg_codec 0 >> &sti_sasg_codec &sti_sasg_codec >> 0 0>; >> backend-codec-dai = "sas-dai-hdmi-out", "snd-soc-dummy-dai", >> "sas-dai-dac", "sas-dai-spdif-out", >> "snd-soc-dummy-dai","snd-soc-dummy-dai"; >> }; > This looks a lot like you're trying to reinvent simple-card. Ok , not see that last versions of simple card manage multi DAI links. i will check if compatible with my design to reuse it instead of my machine driver. Thanks for the remarks.