On Wed, Dec 09, 2009 at 04:32:41PM +0100, Uwe Kleine-König wrote:
> On Wed, Dec 09, 2009 at 08:08:19AM -0700, Grant Likely wrote:
> > (resend because I forgot to cc the mailing list)
> >
> > 2009/12/9 Uwe Kleine-König <[email protected]>:
> > > Hello Grant,
> > >
> > > On Tue, Dec 08, 2009 at 05:38:57PM -0700, Grant Likely wrote:
> > >> > diff -puN
> > >> > drivers/spi/spi_imx.c~spi-imx-correct-check-for-platform_get_irq-failing
> > >> > drivers/spi/spi_imx.c
> > >> > ---
> > >> > a/drivers/spi/spi_imx.c~spi-imx-correct-check-for-platform_get_irq-failing
> > >> > +++ a/drivers/spi/spi_imx.c
> > >> > @@ -554,7 +554,7 @@ static int __init spi_imx_probe(struct p
> > >> > }
> > >> >
> > >> > spi_imx->irq = platform_get_irq(pdev, 0);
> > >> > - if (!spi_imx->irq) {
> > >> > + if (spi_imx->irq < 0) {
> > >>
> > >> This changes the old behaviour. Is that what you intended? '<= 0'
> > >> perhaps?
> > > Yes, the old check was wrong. What if the irq to use is 0? I thought
> > > the commit log to be understandable. platform_get_irq returns -ENXIO on
> > > error and an irq number on success. So 0 has to be interpreted as valid
> > > irq, not an error.
> >
> > 0 is not a valid IRQ
> Hmm, on my x86 I have:
>
> $ grep '\<0:' /proc/interrupts
> 0: 24330 IO-APIC-edge timer
>
> arm/davinci starts at 0, too. As does arm/ns9xxx. arm/pxa seems to
> start at 1. realview starts at 1, too. So four out of five make are
> wrong? Seems like a big area for cleanup.
I've read a bit and I think the best for a driver writer (i.e. the role
I have when changing drivers/spi/spi_imx.c) is to accept what
platform_get_irq returns to me. If the platform specified
struct resource mydevicesresources[] = {
...
{
.start = 0,
.end = 0,
.flags = IORESOURCE_IRQ,
},
...
};
then the best thing to do is to take irq0, isn't it. So as
platform_get_irq is implemented as
int platform_get_irq(struct platform_device *dev, unsigned int num)
{
struct resource *r = platform_get_resource(dev, IORESOURCE_IRQ,
num);
return r ? r->start : -ENXIO;
}
testing for <0 seems right to me.
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |
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