Re: [PATCH v5 02/11] i2c: omap: wakeup the controller during suspend() callback

From: Thomas Richard <thomas.richard@bootlin.com>
To: Bjorn Helgaas <helgaas@kernel.org>
Cc: "Andi Shyti" <andi.shyti@kernel.org>,
	"Linus Walleij" <linus.walleij@linaro.org>,
	"Bartosz Golaszewski" <brgl@bgdev.pl>,
	"Tony Lindgren" <tony@atomide.com>,
	"Aaro Koskinen" <aaro.koskinen@iki.fi>,
	"Janusz Krzysztofik" <jmkrzyszt@gmail.com>,
	"Vignesh R" <vigneshr@ti.com>, "Peter Rosin" <peda@axentia.se>,
	"Lorenzo Pieralisi" <lpieralisi@kernel.org>,
	"Krzysztof Wilczyński" <kw@linux.com>,
	"Rob Herring" <robh@kernel.org>,
	"Bjorn Helgaas" <bhelgaas@google.com>,
	"Siddharth Vadapalli" <s-vadapalli@ti.com>,
	linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-omap@vger.kernel.org, linux-i2c@vger.kernel.org,
	linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	gregory.clement@bootlin.com, theo.lebrun@bootlin.com,
	thomas.petazzoni@bootlin.com, u-kumar1@ti.com,
	"Wolfram Sang" <wsa+renesas@sang-engineering.com>
Subject: Re: [PATCH v5 02/11] i2c: omap: wakeup the controller during suspend() callback
Date: Wed, 24 Apr 2024 12:24:24 +0200	[thread overview]
Message-ID: <8d49f316-bb17-4956-a62b-e64d460825d4@bootlin.com> (raw)
In-Reply-To: <20240422194423.GA414623@bhelgaas>

On 4/22/24 21:44, Bjorn Helgaas wrote:
> On Mon, Apr 22, 2024 at 11:40:02AM +0200, Thomas Richard wrote:
>> On 4/19/24 10:47, Andi Shyti wrote:
>>> Hi Thomas,
>>>
>>>> +static int omap_i2c_suspend(struct device *dev)
>>>> +{
>>>> +	/*
>>>> +	 * If the controller is autosuspended, there is no way to wakeup it once
>>>> +	 * runtime pm is disabled (in suspend_late()).
>>>> +	 * But a device may need the controller up during suspend_noirq() or
>>>> +	 * resume_noirq().
>>>> +	 * Wakeup the controller while runtime pm is enabled, so it is available
>>>> +	 * until its suspend_noirq(), and from resume_noirq().
>>>> +	 */
>>>> +	return pm_runtime_resume_and_get(dev);
>>>> +}
>>>> +
>>>> +static int omap_i2c_resume(struct device *dev)
>>>> +{
>>>> +	pm_runtime_mark_last_busy(dev);
>>>> +	pm_runtime_put_autosuspend(dev);
>>>> +
>>>> +	return 0;
>>>> +}
>>>> +
>>>>  static const struct dev_pm_ops omap_i2c_pm_ops = {
>>>>  	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
>>>>  				      pm_runtime_force_resume)
>>>> +	SET_SYSTEM_SLEEP_PM_OPS(omap_i2c_suspend, omap_i2c_resume)
>>>
>>> If you don't have CONFIG_PM_SLEEP, though, this doesn't compile.
>>
>> Hello Andi,
>>
>> Yes indeed, the __maybe_unused attribute is missing for
>> omap_i2c_suspend() and omap_i2c_resume().
> 
> Isn't there a way to avoid having to use the __maybe_unused attribute?
> 
> E.g., use DEFINE_SIMPLE_DEV_PM_OPS() as is done by these:
> 
>   82f9cefadac4 ("serial: 8250_exar: switch to DEFINE_SIMPLE_DEV_PM_OPS()")
>   f243df0a0be0 ("media: platform: rzg2l-cru: rzg2l-csi2: Switch to RUNTIME_PM_OPS()")
>   6ccc22a5afcb ("net: ravb: Switch to SYSTEM_SLEEP_PM_OPS()/RUNTIME_PM_OPS() and pm_ptr()")

Yes you're right, I don't need the __maybe_unused attribute if I use
NOIRQ_SYSTEM_SLEEP_PM_OPS().

By the way I can add a patch in the series to remove all the
__maybe_unused attributes of this driver.

Regards,

-- 
Thomas Richard, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com