Re: [PATCH] ASoC: ti: Allocate dais dynamically for TDM and audio graph card

From: Sebastian Reichel <sre@kernel.org>
To: Peter Ujfalusi <peter.ujfalusi@ti.com>
Cc: alsa-devel@alsa-project.org, linux-omap@vger.kernel.org,
	Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>,
	Aaro Koskinen <aaro.koskinen@iki.fi>,
	Tony Lindgren <tony@atomide.com>,
	linux-kernel@vger.kernel.org, Merlijn Wajer <merlijn@wizzup.org>,
	Takashi Iwai <tiwai@suse.com>,
	Liam Girdwood <lgirdwood@gmail.com>,
	Mark Brown <broonie@kernel.org>, Pavel Machek <pavel@ucw.cz>,
	"Arthur D ." <spinal.by@gmail.com>,
	Jarkko Nikula <jarkko.nikula@bitmer.com>
Subject: Re: [PATCH] ASoC: ti: Allocate dais dynamically for TDM and audio graph card
Date: Thu, 20 Feb 2020 21:47:33 +0100	[thread overview]
Message-ID: <20200220204733.ktzhmmaytnglr5nh@earth.universe> (raw)
In-Reply-To: <a263a857-bb8a-0e37-6932-dd07df98ad63@ti.com>

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Hi,

On Thu, Feb 20, 2020 at 04:15:22PM +0200, Peter Ujfalusi wrote:
> > I suppose in the end its a question if generic card can provide TDM
> > support.
> 
> Sure it can, but can it handle the switching between the paths based on
> use cases?
> There should be machine level DAPM widgets to kick codec2codec (MDM6600
> - CPAC_voice for example) and also to make sure that when you switch
> between them the system is not going to get misconfigured.
> Switching between CPAC and BT route during call?
> Not allowing VoIP while on call, etc.

I think the main issue is, that based on the route configuration
(which could be a simple DAPM widget generated by the simple-graph-card),
we may need to configure different bitrates. Tony's hack adding
this knowledge to the cpcap driver is very ugly.

> >> In case of B/C you should not have a running stream imho.
> > 
> > I would expect, that MDM6600 codec marks itself as running/stopped
> > based on call state. That should enable DAPM widgets automatically
> > when CPCAP_voice is routed to MDM6600?
> > 
> >> In all cases CPCAP_voice should be able to run the clocks on i2s,
> >> even if it is not used by the audio setup.
> >> Not sure if you can just turn Wl1285 as master, but it is possible
> >> that it is master, but silent when it is not used?
> > 
> > I provided CPCAP registers for BT call, which should be enough to
> > figure this out (I did not yet analyze the results myself).
> 
> I got the datasheet from NXP (thanks for the pointer!), I try to look at
> it in a coming days.

FWIW the datasheet is not for the same chip, but for a similar one.
The audio part seems to be very similar though.

-- Sebastian

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