Re: [PATCH] iio: temperature: ltc2983: avoid string comparison for leak detector

[Nuno Sá]

On Wed, Sep 30, 2026 at 12:52:16PM +0300, Andy Shevchenko wrote:
> On Tue, Sep 29, 2026 at 12:38:22PM -0500, Carlos Casadiego via B4 Relay wrote:
> 
> +Cc: Nathan
> 
> > GCC can determine at compile time that propname cannot match
> > "adi,custom-leak-detector" when __ltc2983_custom_sensor_new() is
> > inlined for some callers, triggering a -Wstring-compare warning.
> > 
> > Pass an explicit flag for leak detectors instead of deriving the sensor
> > type from the firmware property name. This preserves the existing
> > conversion behavior and avoids the constant string comparison.
> 
> ...
> 
> >  __ltc2983_custom_sensor_new(struct ltc2983_data *st, const struct fwnode_handle *fn,
> >  			    const char *propname, const bool is_steinhart,
> > -			    const u32 resolution, const bool has_signed)
> > +			    const u32 resolution, const bool has_signed,
> > +			    const bool is_leak_detector)
> 
> Can we get rid of those strange const qualifiers for booleans. What are they for?

Obviously nothing. They came from a time where I thought they added some readability
value :).

> 
> ...
> 
> > -			if ((index % 2) != 0 && !strcmp(propname, "adi,custom-leak-detector"))
> > +			if ((index % 2) != 0 && is_leak_detector)
> >  				temp = temp * 1000000 + 273150000;
> 
> Hmm... I consider that the compiler warning is just a noise which we should
> ignore or disable. It's doubtfully useful as if it may prove the always false
> or always true cases, it doesn't mean there won't be other cases in the future.
> Do we have any discussion on that warning before?
> 

While I agree with the above, I'm not against the change of having the
boolean against the string comparison (and the warning would be just a
side effect and not the main motivation for the change).

- Nuno Sá

> -- 
> With Best Regards,
> Andy Shevchenko
> 
>