linux-kernel - Re: regulator: BD71837 PMIC resume during noirq phase?

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Message-ID: <75d30918-9474-8a35-c5ed-d28a090a64c9@fi.rohmeurope.com>
Date:   Tue, 14 Jun 2022 09:47:43 +0000
From:   "Vaittinen, Matti" <Matti.Vaittinen@...rohmeurope.com>
To:     Mark Brown <broonie@...nel.org>,
        Martin Kepplinger <martin.kepplinger@...i.sm>
CC:     "lgirdwood@...il.com" <lgirdwood@...il.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
        arm-soc <linux-arm-kernel@...ts.infradead.org>,
        Pengutronix Kernel Team <kernel@...gutronix.de>
Subject: Re: regulator: BD71837 PMIC resume during noirq phase?

On 6/14/22 12:18, Mark Brown wrote:
> On Tue, Jun 14, 2022 at 11:06:06AM +0200, Martin Kepplinger wrote:
> 
>> and regulator_enable() in imx-pgc is called from genpd_resume_noirq().
>>
>> At this point, does any workaround or fix come to your mind I could
>> test? I guess i2c needs to be resumed too...
>>
>> Why does power domain only implement resume_noirq? How could I untangle
>> this?
> 
> Indeed - if a power domain is controlling regulators then I'd not expect
> things to go well if it tries to resume without interrupts, there will
> be some things that can be done purely with GPIOs but that's depending
> on the hardware having wired things up that way and the operations
> needed by the power domain mapping well onto what can be done with
> GPIOs.

In case of BD71837 only the PMIC 'state changes' could be initiated by 
GPIO. And if the state is not 'RUN' the regulator enable/disable state 
can not be controlled by the Linux driver (or - as far as I remember the 
driver I've authored does not support that. It _may_ be there were 
enable/disable register for IDLE/SUSPEND states for _some_ of the 
BD71837 regulators. Some probably had fixed states. In any case, I don't 
think the driver touched them after initial setup).

Best Regards
-- Matti


-- 
The Linux Kernel guy at ROHM Semiconductors

Matti Vaittinen, Linux device drivers
ROHM Semiconductors, Finland SWDC
Kiviharjunlenkki 1E
90220 OULU
FINLAND

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