From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pierre-Louis Bossart Subject: Re: [alsa-devel] [PATCH v2 3/5] ASoC: core: add support to snd_soc_dai_get_sdw_stream() Date: Thu, 10 Oct 2019 09:01:42 -0500 Message-ID: <22eff3aa-dfd6-1ee5-8f22-2af492286053@linux.intel.com> References: <20190813191827.GI5093@sirena.co.uk> <20190813195804.GL5093@sirena.co.uk> <20190814041142.GU12733@vkoul-mobl.Dlink> <99d35a9d-cbd8-f0da-4701-92ef650afe5a@linux.intel.com> <5e08f822-3507-6c69-5d83-4ce2a9f5c04f@linaro.org> <53bb3105-8e85-a972-fce8-a7911ae4d461@linux.intel.com> <95870089-25da-11ea-19fd-0504daa98994@linaro.org> <2326a155-332e-fda0-b7a2-b48f348e1911@linux.intel.com> <34e4cde8-f2e5-0943-115a-651d86f87c1a@linaro.org> <20191010120337.GB31391@ediswmail.ad.cirrus.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20191010120337.GB31391@ediswmail.ad.cirrus.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Charles Keepax , Srinivas Kandagatla Cc: devicetree@vger.kernel.org, alsa-devel@alsa-project.org, bgoswami@codeaurora.org, linux-kernel@vger.kernel.org, plai@codeaurora.org, robh+dt@kernel.org, lgirdwood@gmail.com, Vinod Koul , Mark Brown , spapothi@codeaurora.org List-Id: devicetree@vger.kernel.org >>> It's been a while since this thread started, and I still don't >>> quite get the concepts or logic. >>> >>> First, I don't understand what the problem with "aux" devices is. >>> All the SoundWire stuff is based on the concept of DAI, so I guess >>> I am >> >> That is the actual problem! Some aux devices does not have dais. >> > > Usually aux devices are used for things like analog amplifiers that > clearly don't have a digital interface, thus it really makes no sense > to have a DAI link connecting them. So I guess my question here > would be what is the thinking on making the "smart amplifier" dailess? > It feels like having a CODEC to CODEC DAI between the CODEC and > the AMP would be a more obvious way to connect the two devices > and would presumably avoid the issues being discussed around the > patch. Ah, now I get it, I missed the point about not having DAIs for the amplifier. I will second Charles' point, the code you have in the machine driver at [1] gets a SoundWire stream context from the SLIMbus codec dai. It's a bit odd to mix layers this way. And if I look at the code below, taken from [1], if you have more than one codec, then your code looks problematic: data->sruntime would be overriden and you'd use the info from the last codec dai on the dailink... case SLIMBUS_0_RX...SLIMBUS_6_TX: for (i = 0 ; i < dai_link->num_codecs; i++) { [snip] data->sruntime[cpu_dai->id] = snd_soc_dai_get_sdw_stream(rtd->codec_dais[i], 0); << same destination for multiple codec_dais... If you keep the amp dai-less, then the stream concept should be somehow allocated on the master (or machine) side and passed to the codec dais that are associated to the same 'stream'. [1] https://git.linaro.org/people/srinivas.kandagatla/linux.git/tree/sound/soc/qcom/db845c.c?h=release/db845c/qcomlt-5.2