linux-kernel - Re: [PATCH v2 1/5] Documentation: ABI: add oversampling frequency in sysfs-bus-iio

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Message-ID: <aAe6u6NhAsgjaL5_@smile.fi.intel.com>
Date: Tue, 22 Apr 2025 18:50:19 +0300
From: Andy Shevchenko <andy@...nel.org>
To: Jorge Marques <jorge.marques@...log.com>
Cc: Jonathan Cameron <jic23@...nel.org>,
	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>,
	Jonathan Corbet <corbet@....net>,
	David Lechner <dlechner@...libre.com>,
	Nuno Sá <nuno.sa@...log.com>,
	Uwe Kleine-König <ukleinek@...nel.org>,
	linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org,
	devicetree@...r.kernel.org, linux-doc@...r.kernel.org,
	linux-pwm@...r.kernel.org
Subject: Re: [PATCH v2 1/5] Documentation: ABI: add oversampling frequency in
 sysfs-bus-iio

On Tue, Apr 22, 2025 at 01:34:46PM +0200, Jorge Marques wrote:
> Some devices have an internal clock used to space out the conversion
> trigger for the oversampling filter,
> Consider an ADC with conversion and data ready pins topology:
> 
>   Sampling trigger |       |       |       |       |
>   ADC conversion   ++++    ++++    ++++    ++++    ++++
>   ADC data ready      *       *       *       *       *
> 
> With the oversampling frequency, conversions are spaced:
> 
>   Sampling trigger |       |       |       |       |
>   ADC conversion   + + + + + + + + + + + + + + + + + + + +
>   ADC data ready         *       *       *       *       *
> 
> In some devices and ranges, this internal clock can be used to evenly
> space the conversions between the sampling edge.
> In other devices the oversampling frequency is fixed or is computed
> based on the sampling frequency parameter, and the parameter is
> read only.
> 
> Devices with this feature are max1363, ad7606, ad799x, and ad4052.
> The max1363 driver included the events/sampling_frequency in
> commit 168c9d95a940 ("iio:adc:max1363 move from staging.")
> and ad799x in
> commit ba1d79613df3 ("staging:iio:ad799x: Use event spec for threshold
> hysteresis")
> but went undocumented so far.

So, it was no documentation for the nodes this change describes, right?

...

> +What:		/sys/bus/iio/devices/iio:deviceX/oversampling_frequency
> +KernelVersion:	6.15

Then why don't you put the real version of the first release that has it?

> +Contact:	linux-iio@...r.kernel.org
> +Description:
> +		Some devices have internal clocks for oversampling.
> +		Sets the resulting frequency in Hz to trigger a conversion used by
> +		the oversampling filter.
> +		If the device has a fixed internal clock or is computed based on
> +		the sampling frequency parameter, the parameter is read only.
> +
> +What:		/sys/bus/iio/devices/iio:deviceX/oversampling_frequency_available
> +KernelVersion:	6.15

Ditto.

> +Contact:	linux-iio@...r.kernel.org
> +Description:
> +		Hardware dependent values supported by the oversampling
> +		frequency.

-- 
With Best Regards,
Andy Shevchenko