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Date: Wed, 25 Mar 2015 21:42:02 +0100
From: Pavel Machek <pavel@ucw.cz>
To: "Dr. H. Nikolaus Schaller" <hns@goldelico.com>
Cc: NeilBrown <neilb@suse.de>,
        List for communicating with real GTA04 owners 
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Subject: Re: [Gta04-owner] [PATCH 3/3] tty/slaves: add a driver to power
 on/off UART attached devices.
Message-ID: <20150325204202.GC381@amd>
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Hi!

> > In the case of our GPS, it receives control over the serial connection from
> > the UART,
> 
> Ahem - does it?
> 
> AFAIK the chip simply starts to emit NMEA records if powered on. There is no
> command going over the serial interface to address it or control it.

Well _most_ GPSes enable you to control them over the serial
line. (Things like sampling rate, AGPS data upload, ...)

> > I think the GPS is “primarily" a uart-attached device.
> 
> But not in the same way as an I2C device.
> 
> Especially the serial interface is not a bus and not used for signalling and
> power control. It is payload data (only).

Serial interface looks a lot like a (point-to-point) bus to
me. Similar to SATA, for example.
									Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html