linux-kernel - Re: [PATCH v2] dt-bindings:iio:adc:st,spear600-adc: txt to yaml format conversion.

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Message-ID: <20250503184800.27026-1-rodrigo.gobbi.7@gmail.com>
Date: Sat,  3 May 2025 15:44:12 -0300
From: Rodrigo Gobbi <rodrigo.gobbi.7@...il.com>
To: conor@...nel.org
Cc: conor+dt@...nel.org,
	devicetree@...r.kernel.org,
	jic23@...nel.org,
	krzk+dt@...nel.org,
	linux-iio@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	robh@...nel.org,
	rodrigo.gobbi.7@...il.com,
	~lkcamp/patches@...ts.sr.ht
Subject: Re: [PATCH v2] dt-bindings:iio:adc:st,spear600-adc: txt to yaml format conversion.

> Is 0 the default here or 1? "Single data conversion" sounds more like 1
> sample than 0, and the default of 0 is below the minimum of 1. What's
> going on there?

Good point, after I`ve submitted the patch I was double checking it and noticed 
that too. It`s stange because the public datasheet mentions "Programmable averaging of results 
from 1 (No averaging) up to 128". Meanwhile, the spear_adc.c driver at probe
stated the following:

	/*
	 * Optional avg_samples defaults to 0, resulting in single data
	 * conversion
	 */
	device_property_read_u32(dev, "average-samples", &st->avg_samples);

Since avg_samples is inside 

	struct spear_adc_state *st;

which is allocated with devm_iio_device_alloc() (which uses the kzalloc/zero filling the priv data):

	indio_dev = devm_iio_device_alloc(dev, sizeof(struct spear_adc_state));
	if (!indio_dev)
		return dev_err_probe(dev, -ENOMEM,
				     "failed allocating iio device\n");

	st = iio_priv(indio_dev);

...matches the driver comment meaning the default is actually "0", single data, but it does
not match the public datasheet in my understanding. Since I don`t have access to a more
detailed datasheet, I chose to describe "1" as a minimum value, but I agree it is weird.
Maybe we could drop the minimum constraint in this case (go with default and max)?
Tks and regards.