RE: [PATCH v1] clocksource: tegra: Add nvidia,tegra30-timer compat

From: Thomas Gleixner
Date: Tue Feb 04 2014 - 14:10:16 EST

On Mon, 3 Feb 2014, Andrew Chew wrote:

> > From: Daniel Lezcano [mailto:daniel.lezcano@xxxxxxxxxx]
> > Sent: Monday, February 03, 2014 8:40 AM
> > To: Andrew Chew; tglx@xxxxxxxxxxxxx; swarren@xxxxxxxxxxxxx;
> > thierry.reding@xxxxxxxxx; abrestic@xxxxxxxxxxxx; dgreid@xxxxxxxxxxxx;
> > katierh@xxxxxxxxxxxx
> > Cc: linux-kernel@xxxxxxxxxxxxxxx; linux-tegra@xxxxxxxxxxxxxxx
> > Subject: Re: [PATCH v1] clocksource: tegra: Add nvidia,tegra30-timer compat
> >
> > On 01/31/2014 10:29 PM, Andrew Chew wrote:
> > > There are some differences between tegra20's timer registers and
> > > tegra30's (and later). For one thing, the watchdogs don't seem to be
> > > present in tegra20.
> >
> > "don't seem", so it is an assumption ?
> No, this is not an assumption. It has been verified by other NVIDIA engineers
> since I proposed this change.

So why is your changelog saying "don't seem to be" ?

> > > Add this compatibility string in order to be able to distinguish
> > > whether the watchdogs are there or not.
> >
> > Sorry but I don't get the connection between declaring the tegra30_timer
> > and the log. Can you elaborate please ?
> I don't know what you mean by "the log". Was that a typo? Anyway, I

Daniel refers to the changelog.

> have a watchdog driver that I intend to follow up with, that binds
> with tegra30-timer. I don't want this driver to be able to bind with
> tegra20-timer, because the driver won't actually work on tegra20.

So the changelog should say:

Tegra30 and later have more timer functionality than Tegra20, but
share the clocksource core code.

Add a separate devicetree entry which defaults to the tegra20 code
for now. This is preparatory work for adding new tegra30 specific


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