linux-kernel - Re: [PATCH] gpio: pca953x: Clear irq trigger type on irq shutdown

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Message-ID: <354db10f9a239e04087ba7cf7d731d3fbe2ec066.camel@linux.intel.com>
Date:   Wed, 16 May 2018 16:14:00 +0300
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Linus Walleij <linus.walleij@...aro.org>,
        Grigoryev Denis <grigoryev@...twel.ru>,
        "H. Nikolaus Schaller" <hns@...delico.com>,
        Sergei Shtylyov <sergei.shtylyov@...entembedded.com>,
        Steve Longerbeam <slongerbeam@...il.com>
Cc:     "linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] gpio: pca953x: Clear irq trigger type on irq shutdown

On Wed, 2018-05-16 at 14:51 +0200, Linus Walleij wrote:
> On Fri, May 4, 2018 at 6:53 PM, Grigoryev Denis <grigoryev@...twel.ru>
> wrote:
> 

If it's full context below, the patch looks good enough to me (assuming
it works and doesn't break things on other chips like PCAL variants).

Though, I didn't read the code carefully (not enough time this week).
Thus, FWIW, 

Acked-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>

with above caveats in mind.

> > The driver stores the result of irq_set_type() in the internal
> > variables
> > irq_trig_raise and irq_trig_fall, which later are used to determine
> > the GPIOs that must be re-configured as input. These variables
> > retain their
> > value between gpiolib's  export / unexport, resulting in an
> > incorrect
> > state in some cases. The corresponding bits in the variables
> > irq_trig_raise and irq_trig_fall should be cleared in
> > irq_shutdown().
> > 
> > Signed-off-by: Denis Grigoryev <grigoryev@...twel.ru>
> > ---
> >  drivers/gpio/gpio-pca953x.c | 10 ++++++++++
> >  1 file changed, 10 insertions(+)
> > 
> > diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-
> > pca953x.c
> > index d2ead4b..b41be8c 100644
> > --- a/drivers/gpio/gpio-pca953x.c
> > +++ b/drivers/gpio/gpio-pca953x.c
> > @@ -522,6 +522,15 @@ static int pca953x_irq_set_type(struct irq_data
> > *d, unsigned int type)
> >         return 0;
> >  }
> > 
> > +static void pca953x_irq_shutdown(struct irq_data *d)
> > +{
> > +       struct pca953x_chip *chip = irq_data_get_irq_chip_data(d);
> > +       u8 mask = 1 << (d->hwirq % BANK_SZ);
> > +
> > +       chip->irq_trig_raise[d->hwirq / BANK_SZ] &= ~mask;
> > +       chip->irq_trig_fall[d->hwirq / BANK_SZ] &= ~mask;
> > +}
> > +
> >  static struct irq_chip pca953x_irq_chip = {
> >         .name                   = "pca953x",
> >         .irq_mask               = pca953x_irq_mask,
> > @@ -529,6 +538,7 @@ static struct irq_chip pca953x_irq_chip = {
> >         .irq_bus_lock           = pca953x_irq_bus_lock,
> >         .irq_bus_sync_unlock    = pca953x_irq_bus_sync_unlock,
> >         .irq_set_type           = pca953x_irq_set_type,
> > +       .irq_shutdown           = pca953x_irq_shutdown,
> >  };
> 
> This driver has a big set of users, so putting some maintainers
> in the loop so we can get some patch review.
> 
> Yours,
> Linus Walleij

-- 
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Intel Finland Oy