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Message-ID: <95032042-787e-494a-bad9-81b62653de52@bootlin.com>
Date: Thu, 8 Feb 2024 17:19:25 +0100
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Subject: Re: [PATCH 01/14] gpio: pca953x: move suspend/resume to
 suspend_noirq/resume_noirq
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To: Linus Walleij <linus.walleij@linaro.org>
Cc: Tony Lindgren <tony@atomide.com>, Bartosz Golaszewski <brgl@bgdev.pl>,
 Andy Shevchenko <andy@kernel.org>, Haojian Zhuang
 <haojian.zhuang@linaro.org>, Vignesh R <vigneshr@ti.com>,
 Aaro Koskinen <aaro.koskinen@iki.fi>,
 Janusz Krzysztofik <jmkrzyszt@gmail.com>, Andi Shyti
 <andi.shyti@kernel.org>, Peter Rosin <peda@axentia.se>,
 Vinod Koul <vkoul@kernel.org>, Kishon Vijay Abraham I <kishon@kernel.org>,
 Philipp Zabel <p.zabel@pengutronix.de>, Tom Joseph <tjoseph@cadence.com>,
 Lorenzo Pieralisi <lpieralisi@kernel.org>,
 =?UTF-8?Q?Krzysztof_Wilczy=C5=84ski?= <kw@linux.com>,
 Rob Herring <robh@kernel.org>, Bjorn Helgaas <bhelgaas@google.com>,
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 linux-arm-kernel@lists.infradead.org, linux-omap@vger.kernel.org,
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 linux-pci@vger.kernel.org, gregory.clement@bootlin.com,
 theo.lebrun@bootlin.com, thomas.petazzoni@bootlin.com, u-kumar1@ti.com
References: <20240102-j7200-pcie-s2r-v1-0-84e55da52400@bootlin.com>
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From: Thomas Richard <thomas.richard@bootlin.com>
In-Reply-To: <CACRpkdYUVbFoDq91uLbUy8twtG_AiD+CY2+nqzCyHV7ZyBC3sA@mail.gmail.com>
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On 1/28/24 01:12, Linus Walleij wrote:
> On Fri, Jan 19, 2024 at 6:01 PM Thomas Richard
> <thomas.richard@bootlin.com> wrote:
>> On 1/16/24 08:43, Tony Lindgren wrote:
>>> * Thomas Richard <thomas.richard@bootlin.com> [240115 16:16]:
>>>> Some IOs can be needed during suspend_noirq/resume_noirq.
>>>> So move suspend/resume callbacks to noirq.
>>>
>>> So have you checked that the pca953x_save_context() and restore works
>>> this way? There's i2c traffic and regulators may sleep.. I wonder if
>>> you instead just need to leave gpio-pca953x enabled in some cases
>>> instead?
>>>
>>
>> Yes I tested it, and it works (with my setup).
>> But this patch may have an impact for other people.
>> How could I leave it enabled in some cases ?
> 
> I guess you could define both pca953x_suspend() and
> pca953x_suspend_noirq() and selectively bail out on one
> path on some systems?

Yes.

What do you think if I use a property like for example "ti,pm-noirq" to
select the right path ?
Is a property relevant for this use case ?

Regards,

> 
> Worst case using if (of_machine_is_compatible("my,machine"))...
> 
> Yours,
> Linus Walleij
-- 
Thomas Richard, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com