Re: [PATCH v1 1/1] serial: 8520_mtk: Prepare for platform_get_irq_optional() changes

On Fri, Dec 17, 2021 at 05:54:55PM +0100, Greg Kroah-Hartman wrote:

On Fri, Dec 17, 2021 at 05:10:34PM +0200, Andy Shevchenko wrote:

quoted

The platform_get_irq_optional() is going to be changed in a way
that the result of it:
   = 0 means no IRQ is provided
   < 0 means the error which needs to be propagated to the upper layers
   > 0 valid vIRQ is allocated

What about 0 being a valid irq?

For this driver it can't be possible. The driver is instantiated via DT only
and OF APIs never return 0 for IRQ. If it's the case, it's a regression in the
OF APIs.

I can elaborate in the commit message.

quoted

In this case, drop check for 0. Note, the 0 is not valid vIRQ and
platform_get_irq_optional() issues a big WARN() in such case,

But it still is a valid irq, so why did you just break things?  Yes, a
warning will happen, but the driver and platform will still work.

In general yes, but not in this case. See above.

...

quoted

-	if (irq >= 0)
+	if (irq > 0)
 		disable_irq_wake(irq);

Why change this now?  What does this solve at this point in time?

As explained in the commit message, it's a preparation patch to fix the logic
behind platform_get_irq_optional().

-- 
With Best Regards,
Andy Shevchenko



_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel