Re: [PATCH v2 9/9] iio: adc: ad4062: Add GPIO Controller support

[Andy Shevchenko]

On Fri, Dec 5, 2025 at 1:53 PM Jorge Marques <gastmaier@xxxxxxxxx> wrote:
> On Fri, Dec 05, 2025 at 12:21:31AM +0200, Andy Shevchenko wrote:
> > On Thu, Dec 4, 2025 at 11:38 PM Jorge Marques <gastmaier@xxxxxxxxx> wrote:
> > > On Thu, Nov 27, 2025 at 11:20:54AM +0200, Andy Shevchenko wrote:
> > > > On Wed, Nov 26, 2025 at 04:55:41PM +0100, Jorge Marques wrote:
> > > > > On Mon, Nov 24, 2025 at 12:40:37PM +0200, Andy Shevchenko wrote:
> > > > > > On Mon, Nov 24, 2025 at 10:18:08AM +0100, Jorge Marques wrote:

...

> > > > > > > +       return reg_val == AD4062_GP_STATIC_HIGH ? 1 : 0;
> > > > > >
> > > > > >   return !!(reg_val == AD4062_GP_STATIC_HIGH);
> > > > > >
> > > > > > also will work.
> > > > > >
> > > > >     return reg_val == AD4062_GP_STATIC_HIGH;
> > > >
> > > > Hmm... This will include implicit bool->int. The !! guarantees values 0 or 1,
> > > > but I don't remember about implicit bool->int case.
> >
> > > I don't think the implicit bool->int is an issue, grepping `return .* == .*;`
> > > matches a few methods that return int.
> >
> > Yes, the Q here is the value of true _always_ be promoted to 1?
>
> The relational operator result has type int (c99 6.5.9 Equality
> operators); and when any scalar value is converted to _Bool, the result
> is 0 if the value compares equal to 0; otherwise, the result is 1 (c99
> 6.3.1.2).
> https://www.dii.uchile.cl/~daespino/files/Iso_C_1999_definition.pdf

Okay, thanks for checking this!
So, let's go with a simplified variant then.

> No conversion warnings even when forcing _Bool type.
> There are many usages like this, for example:
>
> drivers/iio/accel/adxl313_core.c @ int adxl313_is_act_inact_ac()
> drivers/iio/light/opt4060.c @ int opt4060_read_event_config()
> drivers/iio/light/tsl2772.c @ int tsl2772_device_id_verify()
> lib/zstd/compress/zstd_fast.c @ int ZSTD_match4Found_branch()
>
> I cannot find many legitimate usage of relational operator with the
> double negation.
>   git ls-files | xargs grep -s 'return !!' | grep '=='

-- 
With Best Regards,
Andy Shevchenko