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Date:   Tue, 29 May 2018 20:06:59 +0200
From:   Wolfram Sang <wsa@the-dreams.de>
To:     Dmitry Osipenko <digetx@gmail.com>
Cc:     Laxman Dewangan <ldewangan@nvidia.com>,
        Thierry Reding <thierry.reding@gmail.com>,
        Jonathan Hunter <jonathanh@nvidia.com>,
        Shardar Shariff Md <smohammed@nvidia.com>,
        linux-tegra@vger.kernel.org, linux-i2c@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1] i2c: tegra: Remove suspend-resume
Message-ID: <20180529180659.f5s56nstykztvykr@ninjato>
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> > Our I2C driver is based on the interrupt. So we have converted the
> > suspend/resume to suspend_noirq and reseume_noirq so that we will not a=
llow the
> > transfer when system interrupt disabled in downstream.
> > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 SET_NOIRQ_SYSTEM=
_SLEEP_PM_OPS(tegra_i2c_suspend, tegra_i2c_resume)
> >=20
> > In shutdown path, where interrupt disabled and still need i2c, we use t=
he
> > bit-bang method via GPIO for i2c transfer.
> In the current upstream kernel suspend/resume can't be simply moved to the
> 'noirq' stage because resume invokes tegra_i2c_init() which uses runtime =
PM and
> that doesn't work with the IRQ's being disabled. But things do not work e=
ven
> with the tegra_i2c_init() changed to work with the disabled IRQ's, like I=
 wrote
> above the I2C transfer fails (due to timeout) and a "fix" for that failur=
e was
> to remove reset_control_assert/deassert from the tegra_i2c_init(). So I'd=
 go for
> a complete suspend/resume removal for now as it is causes problem.

Laxman, are you convinced or do you have still objections?


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