Re: [RFC PATCH 1/1] gpio: pca953x: Allow interrupt support when compiled as module

[Alexander Stein <alexander.stein@xxxxxxxxxxxxxxxxxxxxx>]

On Friday 28 November 2014 16:11:02, Linus Walleij wrote:
> On Thu, Nov 20, 2014 at 3:06 PM, Alexander Stein
> <alexander.stein@xxxxxxxxxxxxxxxxxxxxx> wrote:
> 
> > With commit 2fd36c55264926e268deb50f6de5f43fa5e490f7
> > ("i2c: core: Map OF IRQ at probe time") it seems that there is no need
> > to force this driver to be compiled into the kernel.
> >
> > Signed-off-by: Alexander Stein <alexander.stein@xxxxxxxxxxxxxxxxxxxxx>
> 
> I don't get this at all.
> 
> >  config GPIO_PCA953X_IRQ
> >         bool "Interrupt controller support for PCA953x"
> > -       depends on GPIO_PCA953X=y
> >         select GPIOLIB_IRQCHIP
> >         help
> >           Say yes here to enable the pca953x to be used as an interrupt
> > -         controller. It requires the driver to be built in the kernel.
> > +         controller.
> 
> Why should this *not* be dependent on GPIO_PCA953X?? The config
> flag is only used inside the file that gets built by exactly that
> config flag!
> 
> Just remove the "=y" part of the line and test if you like.

Doh, you're right. Only the =y part should be removed.

> > This is completely untested, as I lack a board capable of running a v3.18-rcX
> > kernel. But I noticed on an older kernel that this driver failed requesting
> > irq 0 during kernel boot. 0 because it's irq parent was not yet probed (also
> > a compiled in driver).
> 
> If the parent is not probed, it should get an -EPROBE_DEFER
> as irq number from the parent and bail out, then that is the actual bug
> that needs fixing.
> 
> > With the mentioned commit this should work now.
> 
> I want it tested before I believe it...

Sure, I'll come back when I could actually test this on a more recent kernel.

Best regards,
Alexander
-- 
Dipl.-Inf. Alexander Stein

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