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

[Sa, Nuno]

> -----Original Message-----
> From: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> Sent: Thursday, March 3, 2022 2:58 PM
> To: Sa, Nuno <Nuno.Sa@xxxxxxxxxx>
> Cc: linux-iio@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Jonathan
> Cameron <jic23@xxxxxxxxxx>; Lars-Peter Clausen <lars@xxxxxxxxxx>
> Subject: Re: [PATCH v3 3/3] iio: temperature: ltc2983: Make use of
> device properties
> 
> [External]
> 
> On Thu, Mar 03, 2022 at 01:31:56PM +0000, Sa, Nuno wrote:
> > Hi Andy,
> >
> > Good that we waited to test this patch. The fundamental logic
> change
> > for fetching and writing the custom tables are fine. That said, there
> > some issues that I had to fix to test the patch. See below...
> 
> Thanks and indeed it's a good news that we caught a bug beforehand.
> 
> > > From: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> > > Sent: Thursday, February 10, 2022 2:55 PM
> 
> ...
> 
> > > -	phandle = of_parse_phandle(child, "adi,cold-junction-handle",
> > > 0);
> > > -	if (phandle) {
> > > -		ret = of_property_read_u32(phandle, "reg",
> > > -					   &thermo-
> > > >cold_junction_chan);
> > > +	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. As this reference
> > is also optional, we need to nullify ref in case we don't find the
> > it. Otherwise fwnode_handle_put() breaks.
> 
> Got it (I hope).
> Lemme go through it again and issue a v4.
> 
> > 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@xxxxxxxxxx>
> 
> I think of v4 where I may add this, but still would be nice to re-review
> and
> check if I got correctly your testing report.

No problem... I will leave the setup up and re-test v4...

- Nuno Sá