Re: [PATCH V5 02/18] pinctrl: tegra: Add suspend and resume support

From: Dmitry Osipenko <digetx@gmail.com>
To: Sowjanya Komatineni <skomatineni@nvidia.com>,
	Linus Walleij <linus.walleij@linaro.org>
Cc: "thierry.reding@gmail.com" <thierry.reding@gmail.com>,
	Jon Hunter <jonathanh@nvidia.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Jason Cooper <jason@lakedaemon.net>,
	Marc Zyngier <marc.zyngier@arm.com>,
	Stefan Agner <stefan@agner.ch>,
	Mark Rutland <mark.rutland@arm.com>,
	Peter De Schrijver <pdeschrijver@nvidia.com>,
	Prashant Gaikwad <pgaikwad@nvidia.com>,
	Stephen Boyd <sboyd@kernel.org>,
	linux-clk <linux-clk@vger.kernel.org>,
	"open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
	jckuo@nvidia.com, Joseph Lo <josephl@nvidia.com>,
	talho@nvidia.com, linux-tegra@vger.kernel.org,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Mikko Perttunen <mperttunen@nvidia.com>,
	spatra@nvidia.com, Rob Herring <robh+dt@kernel.org>,
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
	<devicetree@vger.kernel.org>
Subject: Re: [PATCH V5 02/18] pinctrl: tegra: Add suspend and resume support
Date: Mon, 15 Jul 2019 00:41:57 +0300	[thread overview]
Message-ID: <23f10791-3fff-0e94-2798-6f38a27745d1@gmail.com> (raw)
In-Reply-To: <db7ac8e6-bfad-bc60-b46e-d886025872e4@nvidia.com>

13.07.2019 8:31, Sowjanya Komatineni пишет:
> 
> On 7/4/19 3:40 AM, Dmitry Osipenko wrote:
>> 04.07.2019 10:31, Linus Walleij пишет:
>>> On Sat, Jun 29, 2019 at 5:58 PM Dmitry Osipenko <digetx@gmail.com>
>>> wrote:
>>>
>>>> Oh, also what about GPIO-pinctrl suspend resume ordering .. is it
>>>> okay that pinctrl
>>>> will be resumed after GPIO? Shouldn't a proper pin-muxing be
>>>> selected at first?
>>> Thierry sent some initial patches about this I think. We need to use
>>> device links for this to work properly so he adds support for
>>> linking the pinctrl and GPIO devices through the ranges.
>>>
>>> For links between pin control handles and their consumers, see also:
>>> 036f394dd77f pinctrl: Enable device link creation for pin control
>>> c6045b4e3cad pinctrl: stmfx: enable links creations
>>> 489b64d66325 pinctrl: stm32: Add links to consumers
>>>
>>> I am using STM32 as guinea pig for this, consider adding links also
>>> from the Tegra pinctrl. I might simply make these pinctrl consumer
>>> to producer links default because I think it makes a lot sense.
>> IIUC, currently the plan is to resume pinctrl *after* GPIO for
>> Tegra210 [1]. But this
>> contradicts to what was traditionally done for older Tegras where
>> pinctrl was always
>> resumed first and apparently it won't work well for the GPIO ranges as
>> well. I think this
>> and the other patchsets related to suspend-resume still need some more
>> thought.
>>
>> [1] https://patchwork.kernel.org/patch/11012077/
> 
> Park bit was introduced from Tegra210 onwards and during suspend/resume,
> requirement of gpio restore prior to pinctrl restore is not required for
> prior Tegra210.
> 
> Also currently pinctrl suspend/resume implementation for prior Tegra210
> is not yet upstreamed but having gpio restore prior to pinmux during
> suspend/resume should not cause any issue for prior tegra's as well as
> gpio resume restores pins back to same gpio config as they were during
> suspend entry.
> 

Okay!