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Date:   Mon, 24 Jan 2022 17:18:32 +0200
From:   Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To:     Jonathan Cameron <jic23@kernel.org>
Cc:     Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
        Jonathan Cameron <Jonathan.Cameron@huawei.com>,
        Andreas Kemnade <andreas@kemnade.info>,
        linux-arm-msm@vger.kernel.org, linux-iio@vger.kernel.org,
        linux-kernel@vger.kernel.org, Andy Gross <agross@kernel.org>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Lars-Peter Clausen <lars@metafoo.de>,
        Peter Rosin <peda@axentia.se>
Subject: Re: [PATCH v2 5/5] iio: afe: iio-rescale: Re-use generic struct
 s32_fract
Message-ID: <Ye7DSAN4gdhXfEUs@smile.fi.intel.com>
References: <20220110193104.75225-1-andriy.shevchenko@linux.intel.com>
 <20220110193104.75225-5-andriy.shevchenko@linux.intel.com>
 <20220115185203.567780e8@jic23-huawei>
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Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo
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On Sat, Jan 15, 2022 at 06:52:03PM +0000, Jonathan Cameron wrote:
> On Mon, 10 Jan 2022 21:31:04 +0200
> Andy Shevchenko <andriy.shevchenko@linux.intel.com> wrote:
> 
> > Instead of custom data type re-use generic struct s32_fract.
> > No changes intended.
> > 
> > The new member is put to be the first one to avoid additional
> > pointer arithmetic. Besides that one may switch to use fract
> > member to perform container_of(), which will be no-op in this
> > case, to get struct rescale.
> > 
> > Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> 
> I'm not totally sold on this series showing there is a strong case for
> these macros so interested to hear what others think.

So far no news :-)

> Boiler plate removal is always nice of course...

That's what I considered nice as well.

...

> > I found this better in order how code is structurally (re)organized.
> > I may rebase this on top of ongoing AFE series.
> > 
> > Also reveals possibility to switch to rational best approximation.
> > But this is another story...
> 
> Now that may well justify introducing this shared infrastructure :)

We also have mult_frac() macro which can be extended by mult_fract() for
these structures.

...

> >  	rescale = iio_priv(indio_dev);
> > -
> > +	rescale->source = source;
> 
> There seems to be more reorganizing going on in here than is necessary
> for the function of this patch. At very least, description should
> call it out.  Why move setting source?

Yeah, I agree that this may be in a separate change before of after the series.
I will split.

> >  	rescale->cfg = of_device_get_match_data(dev);
> > -	rescale->numerator = 1;
> > -	rescale->denominator = 1;
> >  
> > -	ret = rescale->cfg->props(dev, rescale);
> > +	fract = &rescale->fract;
> > +	fract->numerator = 1;
> > +	fract->denominator = 1;

> > -	rescale->source = source;
> > -

-- 
With Best Regards,
Andy Shevchenko