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

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Date:   Tue, 14 Jun 2022 11:06:06 +0200
From:   Martin Kepplinger <martin.kepplinger@...i.sm>
To:     matti.vaittinen@...rohmeurope.com, lgirdwood@...il.com,
        broonie@...nel.org
Cc:     linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        arm-soc <linux-arm-kernel@...ts.infradead.org>,
        Pengutronix Kernel Team <kernel@...gutronix.de>
Subject: regulator: BD71837 PMIC resume during noirq phase?

hi Matti,

I heard you've been helpful in the past - thank for that! Here's a
question I'm currently stuck at: In short, imx8mq can't yet resume from
suspend when using the bd71839 pmic via i2c. The original report here,
just for the background:

https://lore.kernel.org/linux-arm-kernel/2d5d3bbec443742506e39488dbfbf724bb4ca93f.camel@puri.sm/T/#u

But here's what I *think* is going on: When the (buck3) regulator from
bd71839 is the power-supply for a power domain (gpu), the power domain
driver can't resume because buck3 can't be enabled when the pmic isn't
running yet. I'm still a bit uncertain, but here's the logs when simply
printing in the respective suspend/resume callbacks:

[  452.199600] bd718xx-pmic bd71837-pmic.2.auto: bd718xx_resume_noirq
[  452.301450] imx-pgc imx-pgc-domain.5: failed to enable regulator: -
ETIMEDOUT
[  452.320593] imx-i2c 30a20000.i2c: i2c_imx_resume
[  452.322152] bd718xx-pmic bd71837-pmic.2.auto: bd718xx_resume
[  452.323853] imx-i2c 30a30000.i2c: i2c_imx_resume
[  452.324778] imx-i2c 30a40000.i2c: i2c_imx_resume
[  452.325017] imx-i2c 30a50000.i2c: i2c_imx_resume

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?

thank you very much,

                            martin