Re: [PATCH] ASoC: cs35l56: Accept values greater than 0 as IRQ numbers

From: Mark Brown
Date: Tue Jun 18 2024 - 11:59:10 EST


On Mon, Jun 17, 2024 at 03:33:59PM +0100, Richard Fitzgerald wrote:
> On 17/06/2024 15:04, Mark Brown wrote:

> > Have all architectures removed 0 as a valid IRQ?

> From discussion threads we can find 0 might still used on x86 for a
> legacy device.

Some of the arm platforms were also an issue in the past, though
possibly they've all been modernised by now. Don't know about other
older architectures.

> But the conversations we can find on this don't seem to exclude passing
> a negative error number, just that 0 can normally be assumed invalid.

Yes, the question was specifically about the assumption that 0 is
invalid. The status of 0 is kind of a mess, people keep assuming that
it isn't valid and it just depends if users of platforms which try to
use 0 trip up over it. Sometimes people work on trying to eliminate
uses of 0 but it tends to get you into older code nobody wants to touch.

> The kerneldoc for SPI says:

> * @irq: Negative, or the number passed to request_irq() to receive
> * interrupts from this device.

Which includes the 0 as valid thing...

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