Re: Nokia N900 sound driver and ECI GPIOs

From: Pavel Machek <pavel@ucw.cz>
To: "Pali Rohár" <pali.rohar@gmail.com>
Cc: Jarkko Nikula <jarkko.nikula@bitmer.com>,
	Tony Lindgren <tony@atomide.com>,
	Peter Ujfalusi <peter.ujfalusi@ti.com>,
	Eduardo Valentin <edubezval@gmail.com>,
	Lars-Peter Clausen <lars@metafoo.de>,
	Aaro Koskinen <aaro.koskinen@iki.fi>, Nishanth Menon <nm@ti.com>,
	Sebastian Reichel <sre@kernel.org>,
	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 sound driver and ECI GPIOs
Date: Sun, 1 Jan 2017 23:36:39 +0100	[thread overview]
Message-ID: <20170101223639.GA13868@amd> (raw)
In-Reply-To: <201701012054.54505@pali>

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Hi!

> I'm looking at original Maemo N900 2.6.28 sound driver and GPIOs which
> controls A/V jack detection.
> 
> For reference source code of that driver can be found e.g. at alsa-devel
> ML [1] [2] or in my linux-n900 git tree, branch v2.6.28-nokia [3].
> 
> In that sound/soc/omap/rx51.c code is function rx51_set_eci_switches()
> which configures 2 gpios: RX51_ECI_SWITCH_1_GPIO = gpio 178 and
> RX51_ECI_SWITCH_2_GPIO = gpio 182 based on "eci mode" input parameter.
> 
> But in mainline kernel code [4] [5] there is no information about gpio 178
> (as RX51_ECI_SWITCH_1_GPIO) and gpio 182 is called as just "eci-switch".
> More interesting part is that "eci-switch" gpio is not used in whole
> mainline code. It is just referenced in Nokia N900 DTS [4]. Looks like
> sound driver in mainline kernel is incomplete.
> 
> Jarkko, you are listed as original author of that driver. Do you (or
> anybody else) remember what that rx51_set_eci_switches() function is
> doing? And what gpio 178 controls? I was even not able to find gpio 178
> in RX-51 Schematics [6].
> 
> And do you know something about Nokia ECI headsets supports for Nokia
> N900. Looks like there is already some kernel code but support for ECI
> bus or multibuttons headset is missing.

What does "ECI" mean?

I'd like to get detection of headset button presses to work in recent
kernels, but could not figure it out :-(.

Are there multi-button headsets compatible with N900?

Best regards,
									Pavel

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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