Re: [PATCH v3 3/3] iio: temperature: ltc2983: Make use of device properties

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

On Thu, Mar 03, 2022 at 04:23:34PM +0200, Andy Shevchenko wrote:
> On Thu, Mar 03, 2022 at 01:31:56PM +0000, Sa, Nuno wrote:
> 
> ...
> 
> > > +	ref = fwnode_find_reference(child, "adi,cold-junction-
> > > handle", 0);
> > > +	if (ref) {
> > 
> > This is nok. It needs to be 'if (IS_ERR(ref))'. We then should return
> > ERR_CAST() in case of errors inside the if block.
> 
> This is a good catch!
> 
> > As this reference
> > is also optional, we need to nullify ref in case we don't find the
> > it. Otherwise fwnode_handle_put() breaks.
> 
> No, this is not correct. fwnode_handle_put() is ERR_PTR aware.

Oh, the ->put() handles that, but the fwnode_call_void_op() doesn't!

This has to be fixed on fwnode level.

> > We also need to use ptr error logic in the other places where
> > fwnode_find_reference() is used. Although, in the other cases
> > the ref is mandatory, so there's no need to care with breaking
> > fwnode_handle_put().
> > 
> > After these changes (I think the changes are straight enough;
> > but I can re-test if you or Jonathan ask for it):
> > 
> > Tested-by: Nuno Sá <nuno.sa@analog.com>

-- 
With Best Regards,
Andy Shevchenko