linux-kernel - Nokia N900 headset detection & MIC Bias + TVOUT

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Message-Id: <201701070007.49137@pali>
Date:   Sat, 7 Jan 2017 00:07:49 +0100
From:   Pali Rohár <pali.rohar@...il.com>
To:     Tony Lindgren <tony@...mide.com>,
        Peter Ujfalusi <peter.ujfalusi@...com>,
        Jarkko Nikula <jarkko.nikula@...mer.com>,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>
Cc:     "Lars-Peter Clausen" <lars@...afoo.de>,
        Aaro Koskinen <aaro.koskinen@....fi>,
        Nishanth Menon <nm@...com>, Sebastian Reichel <sre@...nel.org>,
        Pavel Machek <pavel@....cz>,
        Ivaylo Dimitrov <ivo.g.dimitrov.75@...il.com>,
        joerg Reisenweber <joerg@...nmoko.org>,
        linux-omap@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Nokia N900 headset detection & MIC Bias + TVOUT

Hi!

For jack cable and headset detection in Nokia N900 I would need to 
enable/disable MIC Bias and also enable/disable TVOUT output.

All that is needed in N900 sound driver, file sound/soc/omap/rx51.c. Can 
you help me which functions should I call to enable/disable it 
correctly? In headset detection code I need to be sure that nobody 
(other kernel drivers or userspace via alsamixer) except current 
function could change Bias settings.

MIC Bias is controlled by MICBIAS_CTRL in aic34 'B' part codec, file 
tlv320aic3x.c.

And according to RX-51 Schematics TVOUT is controlled by OMAP3430 pins: 
TV_OUT1 and TV_VFB1. I have not found any references to them in kernel, 
just in omap trm. How is OMAP3430's TV_OUT1 controlled?

(Existing code in Maemo 2.6.28 kernel is doing it by big hack - exports 
function which directly modify MICBIAS_CTRL)

-- 
Pali Rohár
pali.rohar@...il.com

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