linux-kernel - Re: [PATCH v4 03/18] i2c: omap: wakeup the controller during suspend() callback

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Date: Wed, 13 Mar 2024 01:37:35 +0100
From: Andi Shyti <andi.shyti@...nel.org>
To: Thomas Richard <thomas.richard@...tlin.com>
Cc: Linus Walleij <linus.walleij@...aro.org>, 
	Bartosz Golaszewski <brgl@...ev.pl>, Andy Shevchenko <andy@...nel.org>, 
	Tony Lindgren <tony@...mide.com>, Haojian Zhuang <haojian.zhuang@...aro.org>, 
	Vignesh R <vigneshr@...com>, Aaro Koskinen <aaro.koskinen@....fi>, 
	Janusz Krzysztofik <jmkrzyszt@...il.com>, Peter Rosin <peda@...ntia.se>, Vinod Koul <vkoul@...nel.org>, 
	Kishon Vijay Abraham I <kishon@...nel.org>, Philipp Zabel <p.zabel@...gutronix.de>, 
	Lorenzo Pieralisi <lpieralisi@...nel.org>, Krzysztof Wilczyński <kw@...ux.com>, 
	Rob Herring <robh@...nel.org>, Bjorn Helgaas <bhelgaas@...gle.com>, linux-gpio@...r.kernel.org, 
	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, linux-omap@...r.kernel.org, 
	linux-i2c@...r.kernel.org, linux-phy@...ts.infradead.org, linux-pci@...r.kernel.org, 
	gregory.clement@...tlin.com, theo.lebrun@...tlin.com, thomas.petazzoni@...tlin.com, 
	u-kumar1@...com
Subject: Re: [PATCH v4 03/18] i2c: omap: wakeup the controller during
 suspend() callback

Hi Thomas,

On Mon, Mar 04, 2024 at 04:35:46PM +0100, Thomas Richard wrote:
> A device may need the controller up during suspend_noirq() or
> resume_noirq().
> But if the controller is autosuspended, there is no way to wakeup it during
> suspend_noirq() or resume_noirq() because runtime pm is disabled at this
> time.
> 
> The suspend() callback wakes up the controller, so it is available until
> its suspend_noirq() callback (pm_runtime_force_suspend()).
> During the resume, it's restored by resume_noirq() callback
> (pm_runtime_force_resume()). Then resume() callback enables autosuspend.
> 
> So the controller is up during a little time slot in suspend and resume
> sequences even if it's not used.
> 
> Signed-off-by: Thomas Richard <thomas.richard@...tlin.com>

Reviewed-by: Andi Shyti <andi.shyti@...nel.org>

Thanks,
Andi