linux-kernel - Re: [PATCH v3 1/8] Documentation: ABI: add oversampling frequency in sysfs-bus-iio

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Message-ID: <6gn3kr3vlddousquogcxcdnojcawjt24onnvkf3wvl77bhqoxe@qwehcxjdeab5>
Date: Thu, 12 Jun 2025 12:10:25 +0200
From: Jorge Marques <gastmaier@...il.com>
To: Jonathan Cameron <jic23@...nel.org>
Cc: Jorge Marques <jorge.marques@...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>, Jonathan Corbet <corbet@....net>, 
	David Lechner <dlechner@...libre.com>, Nuno Sá <nuno.sa@...log.com>, 
	Andy Shevchenko <andy@...nel.org>, 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 v3 1/8] Documentation: ABI: add oversampling frequency in
 sysfs-bus-iio

On Wed, Jun 11, 2025 at 06:02:52PM +0100, Jonathan Cameron wrote:
> On Tue, 10 Jun 2025 09:34:34 +0200
> Jorge Marques <jorge.marques@...log.com> wrote:
> 
> Trivial: 
> In the patch title use the actual file name of the new ABI.
> 
> add oversampling_frequency in sysfs-bus-iio
> 

Ack.
> 
> > 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.
> > 
> > Signed-off-by: Jorge Marques <jorge.marques@...log.com>
> > ---
> >  Documentation/ABI/testing/sysfs-bus-iio | 17 +++++++++++++++++
> >  1 file changed, 17 insertions(+)
> > 
> > diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio
> > index ef52c427a015cf47bb9847782e13afbee01e9f31..e60367255be89a9acc827ec1a749b729735f60e6 100644
> > --- a/Documentation/ABI/testing/sysfs-bus-iio
> > +++ b/Documentation/ABI/testing/sysfs-bus-iio
> > @@ -139,6 +139,23 @@ Contact:	linux-iio@...r.kernel.org
> >  Description:
> >  		Hardware dependent values supported by the oversampling filter.
> >  
> > +What:		/sys/bus/iio/devices/iio:deviceX/oversampling_frequency
> > +KernelVersion:	6.17
> > +Contact:	linux-iio@...r.kernel.org
> > +Description:
> > +		Some devices have internal clocks for oversampling.
> 
> Wrapping on each sentence is unusual. David pointed this out in v2.
> Wrap at 80 chars as a single paragraph.
> 

Yep, sorry.
Hopefully I develop muscle memory for vim's Vgq soon.

Best regards,
Jorge

> > +		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:	6.17
> > +Contact:	linux-iio@...r.kernel.org
> > +Description:
> > +		Hardware dependent values supported by the oversampling
> > +		frequency.
> > +
> >  What:		/sys/bus/iio/devices/iio:deviceX/in_voltageY_raw
> >  What:		/sys/bus/iio/devices/iio:deviceX/in_voltageY_supply_raw
> >  What:		/sys/bus/iio/devices/iio:deviceX/in_voltageY_i_raw
> > 
>