Re: [PATCH v2 5/9] iio: inkern: Add a helper to query an available minimum raw value

From: Andy Shevchenko <andy.shevchenko@gmail.com>
To: Herve Codina <herve.codina@bootlin.com>
Cc: Liam Girdwood <lgirdwood@gmail.com>,
	Mark Brown <broonie@kernel.org>, Rob Herring <robh+dt@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Jonathan Cameron <jic23@kernel.org>,
	Lars-Peter Clausen <lars@metafoo.de>,
	Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.com>,
	Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>,
	alsa-devel@alsa-project.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org,
	Christophe Leroy <christophe.leroy@csgroup.eu>,
	Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Subject: Re: [PATCH v2 5/9] iio: inkern: Add a helper to query an available minimum raw value
Date: Mon, 5 Jun 2023 12:45:24 +0300	[thread overview]
Message-ID: <CAHp75Vec3fXT6phqvLGSn0c09USCXXF6ZoE+X1VNJGM6jyf=aQ@mail.gmail.com> (raw)
In-Reply-To: <20230605094637.7615b689@bootlin.com>

On Mon, Jun 5, 2023 at 10:46 AM Herve Codina <herve.codina@bootlin.com> wrote:
> On Sat, 3 Jun 2023 17:04:37 +0300
> andy.shevchenko@gmail.com wrote:
> > Tue, May 23, 2023 at 05:12:19PM +0200, Herve Codina kirjoitti:

...

> > > +           case IIO_VAL_INT:
> > > +                   *val = vals[--length];
> >
> > > +                   while (length) {
> >
> >                       while (length--) {
> >
> > will do the job and at the same time...
> >
> > > +                           if (vals[--length] < *val)
> > > +                                   *val = vals[length];
> >
> > ...this construction becomes less confusing (easier to parse).
>
> Indeed, I will change in the next iteration.

And looking into above line, this whole construction I would prefer to
have a macro in minmax.h like

#define min_array(array, len) \
{( \
  typeof(len) __len = (len); \
  typeof(*(array)) __element = (array)[--__len]; \
  while (__len--) \
    __element = min(__element, (array)[__len]); \
  __element; \
)}

(it might need more work, but you got the idea)

> > > +                   }
> > > +                   break;

...

> > > +           default:
> > > +                   /* FIXME: learn about min for other iio values */
> >
> > I believe in a final version this comment won't be here.
>
> We have the same FIXME comment in the iio_channel_read_max() function I
> copied to create this iio_channel_read_min() and, to be honest, I
> don't really know how to handle these other cases.
>
> In this series, I would prefer to keep this FIXME.

I see, Jonathan needs to be involved here then.

> > > +                   return -EINVAL;

-- 
With Best Regards,
Andy Shevchenko