Re: [PATCH] drivers: fwnode: fix fwnode_irq_get_byname() kerneldoc

[Matti Vaittinen]

Hi Sakari,

On 10/25/22 09:48, Sakari Ailus wrote:
> Moi,
>
> On Tue, Oct 25, 2022 at 08:24:24AM +0300, Matti Vaittinen wrote:
> > The fwnode_irq_get_byname() may return zero on device-tree mapping
> > error. Fix documentation to reflect this as current documentation
> > suggests check:
> >
> > if (ret < 0)
> > is enough to detect the errors. This is not the case.
> >
> > Add zero as a return value indicating error.
> >
> > Fixes: ca0acb511c21 ("device property: Add fwnode_irq_get_byname")
> > Suggested-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> > Signed-off-by: Matti Vaittinen <mazziesaccount@xxxxxxxxx>
> > ---
> >   drivers/base/property.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/base/property.c b/drivers/base/property.c
> > index 4d6278a84868..df437d10aa08 100644
> > --- a/drivers/base/property.c
> > +++ b/drivers/base/property.c
> > @@ -960,7 +960,7 @@ EXPORT_SYMBOL(fwnode_irq_get);
> >    * string.
> >    *
> >    * Return:
> > - * Linux IRQ number on success, or negative errno otherwise.
> > + * Linux IRQ number on success, zero or negative errno otherwise.
>
> I wonder if it would be possible instead to always return a negative error
> code on error. Returning zero on error is really unconventional and can be
> expected to be a source of bugs.

Agree, and I did also consider just adding:

if (!ret)
	return -EINVAL; (or another feasible errno)

return ret;

at the end of the fwnode_irq_get_byname().

However, such a functional change would require auditing the existing 
callers which I have no time right now.
if (someone is up to the task)
	be my guest :)
else
	please fix the doc ;)

Yours
	-- Matti

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

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