linux-kernel - Re: [PATCH v3 2/7] mfd: tqmx86: clear GPIO IRQ resource when no IRQ is set

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Message-ID: <9dc9fb4b37f7afa661bf1bb9148e5109b3f4329c.camel@ew.tq-group.com>
Date:   Thu, 05 Aug 2021 15:40:08 +0200
From:   Matthias Schiffer <matthias.schiffer@...tq-group.com>
To:     Lee Jones <lee.jones@...aro.org>
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        Bartosz Golaszewski <bgolaszewski@...libre.com>,
        Andrew Lunn <andrew@...n.ch>,
        Andy Shevchenko <andy.shevchenko@...il.com>,
        linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 2/7] mfd: tqmx86: clear GPIO IRQ resource when no IRQ
 is set

On Thu, 2021-08-05 at 14:30 +0100, Lee Jones wrote:
> On Fri, 16 Jul 2021, Matthias Schiffer wrote:
> 
> > The driver was registering IRQ 0 when no IRQ was set. This leads to
> > warnings with newer kernels.
> > 
> > Clear the resource flags, so no resource is registered at all in this
> > case.
> > 
> > Fixes: 2f17dd34ffed ("mfd: tqmx86: IO controller with I2C, Wachdog and GPIO")
> > Signed-off-by: Matthias Schiffer <matthias.schiffer@...tq-group.com>
> > Reviewed-by: Andrew Lunn <andrew@...n.ch>
> > ---
> > 
> > v2: add Fixes line
> > v3: no changes
> > 
> >  drivers/mfd/tqmx86.c | 2 ++
> >  1 file changed, 2 insertions(+)
> > 
> > diff --git a/drivers/mfd/tqmx86.c b/drivers/mfd/tqmx86.c
> > index ddddf08b6a4c..732013f40e4e 100644
> > --- a/drivers/mfd/tqmx86.c
> > +++ b/drivers/mfd/tqmx86.c
> > @@ -209,6 +209,8 @@ static int tqmx86_probe(struct platform_device *pdev)
> >  
> >  		/* Assumes the IRQ resource is first. */
> >  		tqmx_gpio_resources[0].start = gpio_irq;
> > +	} else {
> > +		tqmx_gpio_resources[0].flags = 0;
> 
> Strange - why is this !0 in the first place?

I don't see anything strange here. DEFINE_RES_IRQ() sets flags to
IORESOURCE_IRQ. We reset it to 0 when there is no IRQ to clear that
resource entry.

An alternative would be to start with an empty entry and only fill in
the fields when an IRQ is used, but that seems more cumbersome than the
current code to me.

> 
> >  	}
> >  
> >  	ocores_platfom_data.clock_khz = tqmx86_board_id_to_clk_rate(board_id);
> 
>