From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andrew Lunn <andrew-g2DYL2Zd6BY@public.gmane.org>
Subject: Re: [PATCH 1/2] arm: mvebu: add RTC support for Armada 370 and
 Armada XP
Date: Tue, 11 Dec 2012 07:00:50 +0100
Message-ID: <20121211060050.GC25466@lunn.ch>
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To: Thomas Petazzoni <thomas.petazzoni-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
Cc: Lior Amsalem <alior-eYqpPyKDWXRBDgjK7y7TUQ@public.gmane.org>, Andrew Lunn <andrew-g2DYL2Zd6BY@public.gmane.org>, Ike Pan <ike.pan-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org>, David Marlin <dmarlin-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, Yehuda Yitschak <yehuday-eYqpPyKDWXRBDgjK7y7TUQ@public.gmane.org>, Jani Monoses <jani.monoses-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org>, Tawfik Bayouk <tawfik-eYqpPyKDWXRBDgjK7y7TUQ@public.gmane.org>, Dan Frazier <dann.frazier-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org>, Eran Ben-Avi <benavi-eYqpPyKDWXRBDgjK7y7TUQ@public.gmane.org>, Leif Lindholm <leif.lindholm-5wv7dgnIgG8@public.gmane.org>, Sebastian Hesselbarth <sebastian.hesselbarth-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>, Jason Cooper <jason-NLaQJdtUoK4Be96aLqz0jA@public.gmane.org>, rtc-linux-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org, Alessandro Zummo <a.zummo-BfzFCNDTiLLj+vYz1yj4TQ@public.gmane.org>, Jon Masters <jcm-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org, Rob Herring <rob.herring-bsGFqQB8/DxBDgjK7y7TUQ@public.gmane.org>, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Chris Van Hoof <vanhoof-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org>, Maen Suleiman <maen-eYqpPyKDWXRBDgjK7y7TUQ@public.gmane.org>, Nadav Haklai <nadavh-eYqpPyKDWXRBDgjK7y7TUQ@public.gmane.org>, Shadi Ammouri <shadi-eYqpPyKDWXRBDgjK7y7TUQ@public.gmane.org>
List-Id: devicetree@vger.kernel.org

On Mon, Dec 10, 2012 at 11:37:23PM +0100, Thomas Petazzoni wrote:
> Dear Grant Likely,
> 
> On Mon, 10 Dec 2012 21:47:55 +0000, Grant Likely wrote:
> 
> > > Maybe an explicit status = "okay" here?
> > 
> > Only necessary if it is typical for the device to get disabled. I don't
> > add status="okay" properties unless it is to enable a device previously
> > disabled with status="disabled"
> 
> Ok, thanks for clarifying what the best practice is. This device being
> internal to the SoC and having no dependency on external components, it
> is indeed always available.

Hi Thomas

This is not actually true. Its dependent on at least one external
component, a battery. The driver determines at load time if the clock
is ticking.

There are a few Kirkwood and XP designs which use an external i2c RTC,
because the battery recommended by Marvell is mechanically not so easy
to attached to the board, in a robust way.

So i expect some boards will disable this from there own .dts file.
However, defaulting to enabled would make sense.

   Andrew