Re: [PATCH] i2c: s3c2410: Properly handle interrupts of number 0

[Wolfram Sang]

So, maybe some words why I accepted this patch.

On Fri, Mar 02, 2018 at 11:19:31AM +0000, Russell King - ARM Linux wrote:
> On Thu, Mar 01, 2018 at 09:34:44PM +0100, Krzysztof Kozlowski wrote:
> > Interrupt number 0 (returned by platform_get_irq()) might be a valid IRQ
> > so do not treat it as an error.  If interrupt 0 was configured, the driver
> > would exit the probe early, before finishing initialization, but with
> > 0-exit status.
> 
> The official position (as stated by Linus) is that interrupt zero is
> not a valid interrupt for peripheral drivers (it may be valid within
> architecture code for things like the x86 PIT, but nothing else.)

I am aware of that situation and I totally agree with the reasoning.

> You need to number your platform interrupts from one rather than zero.

Ack.

> Note that there have been patches proposed to make platform_get_irq()
> return an error rather than returning a value of zero, so changing
> the driver in this way is not a good idea.

I'd much agree to such an approach, yet I didn't see it coming along so
far for years(?) now.

The reason I applied this patch is consistency with the current
interface. The code is wrong with the way platform_get_irq right now
works. This is independent of platform_get_irq should work, I thought.
This needs to be fixed in a seperate series. This patch will not harm
that transition.

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