From: "Pali Rohár" <pali.rohar@gmail.com>
To: Mark Brown <broonie@kernel.org>
Cc: Tony Lindgren <tony@atomide.com>,
Peter Ujfalusi <peter.ujfalusi@ti.com>,
Jarkko Nikula <jarkko.nikula@bitmer.com>,
Liam Girdwood <lgirdwood@gmail.com>,
"Lars-Peter Clausen" <lars@metafoo.de>,
Aaro Koskinen <aaro.koskinen@iki.fi>, Nishanth Menon <nm@ti.com>,
Sebastian Reichel <sre@kernel.org>, Pavel Machek <pavel@ucw.cz>,
Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com>,
joerg Reisenweber <joerg@openmoko.org>,
linux-omap@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: Nokia N900 headset detection & MIC Bias + TVOUT
Date: Mon, 9 Jan 2017 20:29:53 +0100 [thread overview]
Message-ID: <201701092029.53939@pali> (raw)
In-Reply-To: <20170109192201.l3mkro3epzf2ns27@sirena.org.uk>
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On Monday 09 January 2017 20:22:01 Mark Brown wrote:
> On Mon, Jan 09, 2017 at 02:13:17PM +0100, Pali Rohár wrote:
> > So... can I call snd_soc_dapm_mutex_lock(dapm) at function startup,
> > start doing cable detection and when needed call this?
> >
> > snd_soc_dapm_enable_pin_unlocked(dapm, "HS Mic");
> > snd_soc_dapm_sync_unlocked(dapm);
> >
> > And at the end of function revert back "HS Mic" pin status and call
> > snd_soc_dapm_mutex_unlock(dapm)?
>
> You shouldn't need to lock I'd expect, and you'll want to sync at any
> point where you need an actual change. Note that if something holds
> the microphone bias on (like something using the microphone)
> separately then that'll take effect so if you really need things to
> get turned off then that won't work but you probably have trouble
> anyway in that situation.
This is needed for cable/jack detection at time when jack is inserted.
So before it there cannot be any user of (disconnected) microphone.
What I need is to enable mic bias, measure ADC of some time period,
check status of some GPIOs. Then disable mic bias, measure ADC again and
check GPIOs. I in this detection procedure I need to ensure that nobody
changes mic bias. So I though that locking the whole procedure could
ensure that.
--
Pali Rohár
pali.rohar@gmail.com
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next prev parent reply other threads:[~2017-01-09 19:30 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-06 23:07 Nokia N900 headset detection & MIC Bias + TVOUT Pali Rohár
2017-01-09 11:27 ` Mark Brown
2017-01-09 13:13 ` Pali Rohár
2017-01-09 19:22 ` Mark Brown
2017-01-09 19:29 ` Pali Rohár [this message]
2017-01-09 19:38 ` Mark Brown
2017-01-09 20:32 ` Pali Rohár
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