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Message-ID: <feb63292-8739-41b2-9503-c83a6fd930fd@bootlin.com>
Date: Wed, 20 Mar 2024 09:37:21 +0100
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Subject: Re: [PATCH v4 02/18] pinctrl: pinctrl-single: move suspend()/resume()
 callbacks to noirq
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To: Dhruva Gole <d-gole@ti.com>
Cc: Linus Walleij <linus.walleij@linaro.org>,
 Bartosz Golaszewski <brgl@bgdev.pl>, Andy Shevchenko <andy@kernel.org>,
 Tony Lindgren <tony@atomide.com>, 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>,
 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>,
 linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org,
 linux-arm-kernel@lists.infradead.org, linux-omap@vger.kernel.org,
 linux-i2c@vger.kernel.org, linux-phy@lists.infradead.org,
 linux-pci@vger.kernel.org, gregory.clement@bootlin.com,
 theo.lebrun@bootlin.com, thomas.petazzoni@bootlin.com, u-kumar1@ti.com,
 Andy Shevchenko <andy.shevchenko@gmail.com>
References: <20240102-j7200-pcie-s2r-v4-0-6f1f53390c85@bootlin.com>
 <20240102-j7200-pcie-s2r-v4-2-6f1f53390c85@bootlin.com>
 <20240320074431.6yzao3jlyaxuii7c@dhruva>
From: Thomas Richard <thomas.richard@bootlin.com>
In-Reply-To: <20240320074431.6yzao3jlyaxuii7c@dhruva>
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On 3/20/24 08:44, Dhruva Gole wrote:
> Hi,
> 
> On Mar 04, 2024 at 16:35:45 +0100, Thomas Richard wrote:
>> The goal is to extend the active period of pinctrl.
>> Some devices may need active pinctrl after suspend() and/or before
>> resume().
>> So move suspend()/resume() to suspend_noirq()/resume_noirq() in order to
>> have active pinctrl until suspend_noirq() (included), and from
>> resume_noirq() (included).
>>
>> The deprecated API has been removed to use the new one (dev_pm_ops struct).
>>
>> No need to check the pointer returned by dev_get_drvdata(), as
>> platform_set_drvdata() is called during the probe.
>>
>> Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
>> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
>> Signed-off-by: Thomas Richard <thomas.richard@bootlin.com>
>> ---
> 
> I was planning to do this but didn't see particular benefit to it. Do
> you see the benefit on your specific device? Can you help me understand
> how? Not against the patch, just curious.

Hello Dhruva,

We need this patch to support suspend to ram for the PCIe on J7200.
In root complex mode, a gpio is used to reset endpoints.
This gpio shall be managed during suspend_noirq and resume_noirq stages.
On J7200 this gpio is on a gpio expander.
So we need this patch to restore pinctrl to be able to do i2c accesses
in noirq stages.

Best Regards,

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