linux-kernel - Re: [PATCHv3 08/16] clk: mvebu: add suspend/resume for gatable clocks

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Message-ID: <20141125074801.1656b78b@free-electrons.com>
Date:	Tue, 25 Nov 2014 07:48:01 +0100
From:	Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>
To:	Mike Turquette <mturquette@...aro.org>
Cc:	"Jason Cooper" <jason@...edaemon.net>,
	"Andrew Lunn" <andrew@...n.ch>,
	"Sebastian Hesselbarth" <sebastian.hesselbarth@...il.com>,
	"Gregory Clement" <gregory.clement@...e-electrons.com>,
	linux-arm-kernel@...ts.infradead.org,
	"Tawfik Bayouk" <tawfik@...vell.com>,
	"Nadav Haklai" <nadavh@...vell.com>,
	"Lior Amsalem" <alior@...vell.com>,
	"Ezequiel Garcia" <ezequiel.garcia@...e-electrons.com>,
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCHv3 08/16] clk: mvebu: add suspend/resume for gatable
 clocks

Mike,

On Mon, 24 Nov 2014 22:07:00 -0800, Mike Turquette wrote:
> Quoting Thomas Petazzoni (2014-11-21 08:00:05)
> > This commit adds suspend/resume support for the gatable clock driver
> > used on Marvell EBU platforms. When getting out of suspend, the
> > Marvell EBU platforms go through the bootloader, which re-enables all
> > gatable clocks. However, upon resume, the clock framework will not
> > disable again all gatable clocks that are not used.
> > 
> > Therefore, if the clock driver does not save/restore the state of the
> > gatable clocks, all gatable clocks that are not claimed by any device
> > driver will remain enabled after a resume. This is why this driver
> > saves and restores the state of those clocks.
> > 
> > Since clocks aren't real devices, we don't have the normal ->suspend()
> > and ->resume() of the device model, and have to use the ->suspend()
> > and ->resume() hooks of the syscore_ops mechanism. This mechanism has
> > the unfortunate idea of not providing a way of passing private data,
> > which requires us to change the driver to make the assumption that
> > there is only once instance of the gatable clock control structure.
> > 
> > Signed-off-by: Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>
> > Cc: Mike Turquette <mturquette@...aro.org>
> > Cc: linux-kernel@...r.kernel.org
> > Acked-by: Gregory CLEMENT <gregory.clement@...e-electrons.com>
> 
> Looks good to me. Which tree do you plan to take this through?

I don't have any specific plans. Jason, do you have other clk changes
for 3.19, which justify a pull request from you to Mike? Or could Mike
just take this patch in his tree? There is no build dependency between
this patch and the other patches in the series, so it can go through
whatever tree.

Thanks,

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
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