linux-kernel - Re: [PATCH v2 4/5] mfd: tqmx86: make IRQ setup errors non-fatal

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Date: Mon, 24 Jun 2024 09:43:53 +0200
From: Matthias Schiffer <matthias.schiffer@...tq-group.com>
To: Lee Jones <lee@...nel.org>
Cc: linux-kernel@...r.kernel.org, Gregor Herburger
	 <gregor.herburger@...group.com>, linux@...tq-group.com
Subject: Re: [PATCH v2 4/5] mfd: tqmx86: make IRQ setup errors non-fatal

On Thu, 2024-06-20 at 17:35 +0100, Lee Jones wrote:
> 
> On Mon, 17 Jun 2024, Matthias Schiffer wrote:
> 
> > GPIO IRQ setup can fail either because an invalid IRQ was passed as a
> > parameter, or because the GPIO controller does not support interrupts.
> > Neither is severe enough to stop the whole probe; simply disable IRQ
> > support in the GPIO resource when setup fails.
> > 
> > Signed-off-by: Matthias Schiffer <matthias.schiffer@...tq-group.com>
> > ---
> > 
> > v2: no changes (was patch 3/4)
> > 
> >  drivers/mfd/tqmx86.c | 7 ++++---
> >  1 file changed, 4 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/mfd/tqmx86.c b/drivers/mfd/tqmx86.c
> > index 5aa51ead00a28..7f9ccd83278dd 100644
> > --- a/drivers/mfd/tqmx86.c
> > +++ b/drivers/mfd/tqmx86.c
> > @@ -259,13 +259,14 @@ static int tqmx86_probe(struct platform_device *pdev)
> >  		err = tqmx86_setup_irq(dev, "GPIO", gpio_irq, io_base,
> >  				       TQMX86_REG_IO_EXT_INT_GPIO_SHIFT);
> >  		if (err)
> > -			return err;
> > +			gpio_irq = 0;
> > +	}
> >  
> > +	if (gpio_irq)
> 
> Stacking identical if()s one after another doesn't sound very efficient.
> 
> Why not put the contents of this one inside the one above?

The intention was to have the "else" branch be executed both when gpio_irq was reset to 0 in the
above error path, and when gpio_irq was 0 in the first place (so the above section running
tqmx86_setup_irq() hasn't even been executed).

I got a better idea now however - by initializing flags to 0 and only setting it together with the
IRQ in the success path, no (!gpio_irq) branch is needed here at all. Will change in v3.

Best regards,
Matthias



> 
> >  		/* Assumes the IRQ resource is first. */
> >  		tqmx_gpio_resources[0].start = gpio_irq;
> > -	} else {
> > +	else
> >  		tqmx_gpio_resources[0].flags = 0;
> > -	}
> >  
> >  	ocores_platform_data.clock_khz = tqmx86_board_id_to_clk_rate(dev, board_id);
> >  
> > -- 
> > TQ-Systems GmbH | Mühlstraße 2, Gut Delling | 82229 Seefeld, Germany
> > Amtsgericht München, HRB 105018
> > Geschäftsführer: Detlef Schneider, Rüdiger Stahl, Stefan Schneider
> > https://www.tq-group.com/
> > 
> 

-- 
TQ-Systems GmbH | Mühlstraße 2, Gut Delling | 82229 Seefeld, Germany
Amtsgericht München, HRB 105018
Geschäftsführer: Detlef Schneider, Rüdiger Stahl, Stefan Schneider
https://www.tq-group.com/