Re: [PATCH v5 4/8] pinctrl: wpcm450: relax return value check for IRQ get

[Matti Vaittinen]

On 5/21/23 20:20, andy.shevchenko@xxxxxxxxx wrote:
> Fri, May 19, 2023 at 02:02:16PM +0300, Matti Vaittinen kirjoitti:
> > fwnode_irq_get[_byname]() were changed to not return 0 anymore. The
> > special error case where device-tree based IRQ mapping fails can't no
> > longer be reliably detected from this return value. This yields a
> > functional change in the driver where the mapping failure is treated as
> > an error.
> >
> > The mapping failure can occur for example when the device-tree IRQ
> > information translation call-back(s) (xlate) fail, IRQ domain is not
> > found, IRQ type conflicts, etc. In most cases this indicates an error in
> > the device-tree and special handling is not really required.
> >
> > One more thing to note is that ACPI APIs do not return zero for any
> > failures so this special handling did only apply on device-tree based
> > systems.
> >
> > Drop the special (no error, just skip the IRQ) handling for DT mapping
> > failures as these can no longer be separated from other errors at driver
> > side.
>
> ...
>
> > The commit message does not mention if choosing not to abort the probe
> > on device-tree mapping failure (as is done on other errors) was chosen
> > because: a) Abort would have broken some existing setup. b) Because skipping
> > an IRQ on failure is "the right thing to do", or c) because it sounded like
> > a way to minimize risk of breaking something.
> >
> > If the reason is a) - then I'd appreciate receiving some more
> > information and a suggestion how to proceed (if possible). If the reason
> > is b), then it might be best to just skip the IRQ instead of aborting
> > the probe for all errors on IRQ getting. Finally, in case of c), well,
> > by acking this change you will now accept the risk :)
>
> No need to repeat this. As I answered the case c) was in my mind when I made
> that change.

True. I'll drop that if I re-spin. Thanks for pointing it out.


Yours,
	-- Matti

--
Matti Vaittinen
Linux kernel developer at ROHM Semiconductors
Oulu Finland

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