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

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Message-ID: <20200218163515.rxdvv5ponu2ndwn7@earth.universe>
Date:   Tue, 18 Feb 2020 17:35:15 +0100
From:   Sebastian Reichel <sebastian.reichel@...labora.com>
To:     Tony Lindgren <tony@...mide.com>
Cc:     Peter Ujfalusi <peter.ujfalusi@...com>,
        Mark Brown <broonie@...nel.org>,
        Liam Girdwood <lgirdwood@...il.com>,
        Jaroslav Kysela <perex@...ex.cz>,
        Takashi Iwai <tiwai@...e.com>, alsa-devel@...a-project.org,
        linux-kernel@...r.kernel.org, linux-omap@...r.kernel.org,
        Aaro Koskinen <aaro.koskinen@....fi>,
        "Arthur D ." <spinal.by@...il.com>,
        Jarkko Nikula <jarkko.nikula@...mer.com>,
        Merlijn Wajer <merlijn@...zup.org>, Pavel Machek <pavel@....cz>
Subject: Re: [PATCH] ASoC: ti: Allocate dais dynamically for TDM and audio
 graph card

Hi,

On Tue, Feb 18, 2020 at 06:19:05AM -0800, Tony Lindgren wrote:
> * Sebastian Reichel <sebastian.reichel@...labora.com> [200218 06:05]:
> > On Fri, Feb 14, 2020 at 09:09:46AM -0800, Tony Lindgren wrote:
> > > * Sebastian Reichel <sre@...nel.org> [200214 13:05]:
> > > > On Thu, Feb 13, 2020 at 05:34:54PM -0800, Tony Lindgren wrote:
> > > > > And bluetooth would be similar to cpcap_audio and mot_mdm6600_audio
> > > > > above.
> > > > 
> > > > My understanding is, that CPU is not involved for calls (except for
> > > > setting up cpcap registers correctly). Basically McBSP3 should
> > > > remain idle for a call and data goes directly from modem to cpcap.
> > > > The same should work for modem <-> BT, except that CPCAP seems to
> > > > always provide the clock. That would imply a direct link between
> > > > modem and codec / BT?
> > > 
> > > Yes the direct link is i2s. I'm ot sure if mcbsp can be idle during
> > > voice call though, I guess it should be doable since mcbsp is not
> > > the clock master :)
> > > 
> > > > > My guess is that only cpcap registers and clock rate needs to be
> > > > > changed for bluetooth audio BTW, so if somebody havs a bluetooth
> > > > > headset just do the following in Android:
> > > > > 
> > > > > # cpcaprw --all > /tmp/before
> > > > > configure bluetooth headset for audio in android and start
> > > > > playing some music or make a phone call
> > > > > ...
> > > > > # cpcaprw --all > /tmp/after
> > > > > stop playing music or phone call
> > > > > ...
> > > > > diff -u /tmp/before /tmp/after
> > > > > 
> > > > > The registers will be different for a bluetooth phone call and
> > > > > playing music.
> > > > 
> > > > I can provider register values once I find some time.
> > 
> > [NI] Normal idle (no BT headset connected)
> > [BI] Bluetooth idle (with BT headset connected)
> > [BC] Bluetooth call in progress
> > [NC] Normal call in progress (BT headset disabled)
> > 
> >                      [NI]  =>  [BI]  =>  [BC]  =>  [NC]
> > CPCAP_REG_VAUDIOC   0x0065 => 0x0065 => 0x0065 => 0x0025
> > CPCAP_REG_CC        0x0000 => 0x0000 => 0x6000 => 0x60df
> > CPCAP_REG_CDI       0x0040 => 0x0000 => 0xaa40 => 0xae0a
> > CPCAP_REG_SDAC      -------------- 0x0000 --------------
> > CPCAP_REG_SDACDI    -------------- 0x0004 --------------
> > CPCAP_REG_TXI       0x0804 => 0x0004 => 0x0000 => 0x0cc6
> > CPCAP_REG_TXMP      0x079c => 0x079c => 0x0400 => 0x0673
> > CPCAP_REG_RXOA      0x0000 => 0x0000 => 0x0001 => 0x0001
> > CPCAP_REG_RXVC      0x0d34 => 0x0d34 => 0x0000 => 0x0b2c
> > CPCAP_REG_RXCOA     0x0000 => 0x0000 => 0x0000 => 0x0601
> > CPCAP_REG_RXSDOA    0x0000 => 0x0000 => 0x0600 => 0x0600
> > CPCAP_REG_RXEPOA    -------------- 0x0400 --------------
> > CPCAP_REG_RXLL      -------------- 0x0000 --------------
> > CPCAP_REG_A2LA      -------------- 0x0030 --------------
> > CPCAP_REG_MIPIS1    -------------- 0x0000 --------------
> > CPCAP_REG_MIPIS2    -------------- 0x0000 --------------
> > CPCAP_REG_MIPIS3    -------------- 0x0000 --------------
> > CPCAP_REG_LVAB      -------------- 0x0000 --------------
> 
> Great thanks! Care to do also a dump just playing music to on
> bluetooth headset at some point?

AFAIK BT music is usually done via A2DP using the data connection,
but I can get a register dump to make sure. I guess the more
interesting bit would be to use BT headset for a VOIP call, which
requires the headset profile being routed to the CPU.

-- Sebastian

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