linux-kernel - Re: [PATCH v4 3/5] iio: adc: ad7606: add offset and phase calibration support

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Message-ID: <aBz6am83scKywvkn@smile.fi.intel.com>
Date: Thu, 8 May 2025 21:39:38 +0300
From: Andy Shevchenko <andy@...nel.org>
To: Angelo Dureghello <adureghello@...libre.com>
Cc: Jonathan Cameron <jic23@...nel.org>,
	David Lechner <dlechner@...libre.com>,
	Nuno Sá <nuno.sa@...log.com>,
	Lars-Peter Clausen <lars@...afoo.de>,
	Michael Hennerich <Michael.Hennerich@...log.com>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>, linux-iio@...r.kernel.org,
	linux-kernel@...r.kernel.org, devicetree@...r.kernel.org
Subject: Re: [PATCH v4 3/5] iio: adc: ad7606: add offset and phase
 calibration support

On Thu, May 08, 2025 at 12:06:07PM +0200, Angelo Dureghello wrote:
> From: Angelo Dureghello <adureghello@...libre.com>
> 
> Add support for offset and phase calibration, only for
> devices that support software mode, that are:
> 
> ad7606b
> ad7606c-16
> ad7606c-18

...

> +static int ad7606_get_calib_offset(struct ad7606_state *st, int ch, int *val)
> +{
> +	int ret;
> +
> +	ret = st->bops->reg_read(st, AD7606_CALIB_OFFSET(ch));
> +	if (ret < 0)
> +		return ret;

> +	*val = st->chip_info->calib_offset_avail[0] + ret *
> +		st->chip_info->calib_offset_avail[1];

You are too fast with new versions... As I pointed out, this is not a logical
split. My only concern was the column, i.e. to be as

	*val = st->chip_info->calib_offset_avail[0] +
	       ret * st->chip_info->calib_offset_avail[1];

> +	return 0;
> +}

...

> +	val -= start_val;
> +	val /= step_val;

Hmm...

To me the

	val = (val - start_val) / step_val;

looks better as it immediately gives an idea of the initial content of the val.
Ideally I would even add a new temporary variable for this, so the operand and
the assignee won't be the same variable.

> +	return st->bops->reg_write(st, AD7606_CALIB_OFFSET(ch), val);

-- 
With Best Regards,
Andy Shevchenko