Nokia N900 headset detection & MIC Bias + TVOUT

From	Pali Rohár <pali.rohar@gmail.com>
Newsgroups	linux.kernel
Subject	Nokia N900 headset detection & MIC Bias + TVOUT
Date	2017-01-07 00:10 +0100
Message-ID	<sWLO3-sV-59@gated-at.bofh.it> (permalink)
Organization	linux.* mail to news gateway

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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@gmail.com

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Nokia N900 headset detection & MIC Bias + TVOUT Pali Rohár <pali.rohar@gmail.com> - 2017-01-07 00:10 +0100
  Re: Nokia N900 headset detection & MIC Bias + TVOUT Mark Brown <broonie@kernel.org> - 2017-01-09 12:40 +0100
    Re: Nokia N900 headset detection & MIC Bias + TVOUT Pali Rohár <pali.rohar@gmail.com> - 2017-01-09 14:20 +0100
      Re: Nokia N900 headset detection & MIC Bias + TVOUT Mark Brown <broonie@kernel.org> - 2017-01-09 20:30 +0100
        Re: Nokia N900 headset detection & MIC Bias + TVOUT Pali Rohár <pali.rohar@gmail.com> - 2017-01-09 20:40 +0100
          Re: Nokia N900 headset detection & MIC Bias + TVOUT Mark Brown <broonie@kernel.org> - 2017-01-09 20:40 +0100
            Re: Nokia N900 headset detection & MIC Bias + TVOUT Pali Rohár <pali.rohar@gmail.com> - 2017-01-09 21:40 +0100

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