Hello!

On 11.12.2021 2:45, Damien Le Moal wrote:

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platform_get_irq() will print a message when it fails.
No need to repeat this.

While at it, drop redundant check for 0 as platform_get_irq() spills
out a big WARN() in such case.

The reason you should be able to remove the "if (!irq)" test is that
platform_get_irq() never returns 0. At least, that is what the function kdoc
says. But looking at platform_get_irq_optional(), which is called by
platform_get_irq(), the out label is:

	WARN(ret == 0, "0 is an invalid IRQ number\n");
	return ret;

So 0 will be returned as-is. That is rather weird. That should be fixed to
return -ENXIO:

	if (WARN(ret == 0, "0 is an invalid IRQ number\n"))
		return -ENXIO;
	return ret;

    My unmerged patch (https://marc.info/?l=linux-kernel&m=163623041902285) does this
but returns -EINVAL instead.

Thinking more about this, shouldn't this change go into platform_get_irq()
instead of platform_get_irq_optional() ?

    Why? platform_get_irq() currently just calls platform_get_irq_optional()...

The way I see it, I think that the intended behavior for
platform_get_irq_optional() is:
1) If have IRQ, return it, always > 0
2) If no IRQ, return 0

    That does include the IRQ0 case, right?

3) If error, return < 0
no ?

   I completely agree, I (after thinking a bit) have no issues with that...

And for platform_get_irq(), case (2) becomes an error.
Is this the intended semantic ?

    I don't see how it's different from the current behavior. But we can do 
that as well, I just don't see whether it's really better...

I am really not sure here as the functions kdoc description and the code do not
match. Which one is correct ?

    It seems both are wrong. :-)

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MBR, Sergey