linux-kernel - Re: [PATCH 3/3] gpio: sch: Enable IRQ support for Quark X1000

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Date:	Fri, 26 Sep 2014 12:18:05 +0300
From:	'Mika Westerberg' <mika.westerberg@...ux.intel.com>
To:	"Chang, Rebecca Swee Fun" <rebecca.swee.fun.chang@...el.com>
Cc:	Linus Walleij <linus.walleij@...aro.org>,
	"linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 3/3] gpio: sch: Enable IRQ support for Quark X1000

On Fri, Sep 26, 2014 at 09:14:48AM +0000, Chang, Rebecca Swee Fun wrote:
> > > @@ -203,6 +376,17 @@ static int sch_gpio_probe(struct platform_device
> > *pdev)
> > >  				 pdev->name))
> > >  		return -EBUSY;
> > >
> > > +	irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
> > > +	sch->irq_support = !!irq;
> > > +	if (sch->irq_support) {
> > > +		sch->irq_num = irq->start;
> > > +		if (sch->irq_num < 0) {
> > > +			dev_warn(&pdev->dev,
> > > +				 "failed to obtain irq number for device\n");
> > > +			sch->irq_support = 0;
> > > +		}
> > > +	}
> > > +
> > >  	spin_lock_init(&sch->lock);
> > >  	sch->iobase = res->start;
> > >  	sch->chip = sch_gpio_chip;
> > > @@ -251,17 +435,72 @@ static int sch_gpio_probe(struct platform_device
> > *pdev)
> > >  		return -ENODEV;
> > >  	}
> > >
> > > +	err = gpiochip_add(&sch->chip);
> > > +	if (err < 0)
> > > +		goto err_sch_gpio;
> > > +
> > > +	if (sch->irq_support) {
> > > +		sch->irq_base = irq_alloc_descs(-1, 0, sch->chip.ngpio,
> > > +						NUMA_NO_NODE);
> > > +		if (sch->irq_base < 0) {
> > > +			dev_err(&pdev->dev,
> > > +				"failed to add GPIO IRQ descs\n");
> > > +			sch->irq_base = -1;
> > > +			goto err_sch_intr_chip;
> > > +		}
> > 
> > Was there some reason why you can't use gpiochip_irqchip_* helpers here?
> 
> I will look into the helpers function and see what I can change here.
> 
> > 
> > > +
> > > +		/* disable interrupts */
> > > +		sch_gpio_irq_disable_all(sch, sch->chip.ngpio);
> > > +
> > > +		err = request_irq(sch->irq_num, sch_gpio_irq_handler,
> > > +				  IRQF_SHARED, KBUILD_MODNAME, sch);
> > 
> > This seems weird, typically irqchip drivers don't call request_irq() directly but
> > instead irq_set_chained_handler() or similar. With
> > gpiochip_irqchip_* stuff you don't need even that.
> > 
> Regarding this, gpio-sch is actually using shared interrupts and the
> IRQ resources are from ACPI SCI. As per my understanding, resources
> from ACPI SCI might be shared for power management purposes. In this
> case, irq_set_chained_handler() might not be able to use here. What do
> you think?

I think you are right. And then you can't use gpiochip_irqchip_* helpers
either :-(
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