linux-kernel - Re: [PATCH v2 1/3] spi: spi-fsl-dspi: Fix external abort on interrupt in exit paths

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Date:   Mon, 15 Jun 2020 17:23:28 +0300
From:   Vladimir Oltean <olteanv@...il.com>
To:     Krzysztof Kozlowski <krzk@...nel.org>
Cc:     Mark Brown <broonie@...nel.org>,
        Marc Kleine-Budde <mkl@...gutronix.de>,
        Thomas Gleixner <tglx@...utronix.de>,
        Vladimir Oltean <vladimir.oltean@....com>,
        linux-spi <linux-spi@...r.kernel.org>,
        lkml <linux-kernel@...r.kernel.org>,
        Wolfram Sang <wsa@...nel.org>, stable@...r.kernel.org,
        Pengutronix Kernel Team <kernel@...gutronix.de>
Subject: Re: [PATCH v2 1/3] spi: spi-fsl-dspi: Fix external abort on interrupt
 in exit paths

On Mon, 15 Jun 2020 at 16:41, Krzysztof Kozlowski <krzk@...nel.org> wrote:
>
> On Mon, Jun 15, 2020 at 04:12:28PM +0300, Vladimir Oltean wrote:
> > On Mon, 15 Jun 2020 at 16:10, Mark Brown <broonie@...nel.org> wrote:
> >
> > >
> > > It's a bit unusual to need to actually free the IRQ over suspend -
> > > what's driving that requirement here?
> >
> > clk_disable_unprepare(dspi->clk); is driving the requirement - same as
> > in dspi_remove case, the module will fault when its registers are
> > accessed without a clock.
>
> In few cases when I have shared interrupt in different drivers, they
> were just disabling it during suspend. Why it has to be freed?
>
> Best regards,
> Krzysztof
>

Not saying it _has_ to be freed, just to be prevented from running
concurrently with us disabling the clock.
But if we can get away in dspi_suspend with just disable_irq, can't we
also get away in dspi_remove with just devm_free_irq?

-Vladimir