From: Oleksij Rempel <o.rempel@pengutronix.de>
To: Jonathan Cameron <jic23@kernel.org>
Cc: Rob Herring <robh+dt@kernel.org>,
devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
Pengutronix Kernel Team <kernel@pengutronix.de>,
David Jander <david@protonic.nl>,
Robin van der Gracht <robin@protonic.nl>,
linux-iio@vger.kernel.org, Lars-Peter Clausen <lars@metafoo.de>,
Peter Meerwald-Stadler <pmeerw@pmeerw.net>,
Dmitry Torokhov <dmitry.torokhov@gmail.com>
Subject: Re: [PATCH v5 1/3] dt-bindings:iio:adc: add generic settling-time-us and oversampling-ratio channel properties
Date: Mon, 29 Mar 2021 15:06:20 +0200 [thread overview]
Message-ID: <20210329130620.utfdlgwzixrenqka@pengutronix.de> (raw)
In-Reply-To: <20210329112532.174825d6@jic23-huawei>
On Mon, Mar 29, 2021 at 11:25:32AM +0100, Jonathan Cameron wrote:
> On Mon, 29 Mar 2021 09:31:29 +0200
> Oleksij Rempel <o.rempel@pengutronix.de> wrote:
>
> > Settling time and over sampling is a typical challenge for different IIO ADC
> > devices. So, introduce channel specific settling-time-us and oversampling-ratio
> > properties to cover this use case.
> >
> > Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
> > ---
> > Documentation/devicetree/bindings/iio/adc/adc.yaml | 8 ++++++++
> > 1 file changed, 8 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/iio/adc/adc.yaml b/Documentation/devicetree/bindings/iio/adc/adc.yaml
> > index 912a7635edc4..d5bc86d2a2af 100644
> > --- a/Documentation/devicetree/bindings/iio/adc/adc.yaml
> > +++ b/Documentation/devicetree/bindings/iio/adc/adc.yaml
> > @@ -39,4 +39,12 @@ properties:
> > The first value specifies the positive input pin, the second
> > specifies the negative input pin.
> >
> > + settling-time-us:
> > + description:
> > + Time between enabling the channel and firs stable readings.
>
> first
ack
> > +
> > + oversampling-ratio:
> > + $ref: /schemas/types.yaml#/definitions/uint32
> > + description: Number of data samples which are averaged for each read.
>
> I think I've asked about this in previous reviews, but I want a clear statement
> of why you think this property is a feature of the 'board' (and hence should be
> in device tree) rather than setting sensible defaults and leaving any control
> to userspace?
yes, my reply was:
> Oversampling is used as replacement of or addition to the low-pass filter. The
> filter can be implemented on board, but it will change settling time
> characteristic. Since low-pass filter is board specific characteristic, this
> property belongs in device tree as well.
I could imagine that this values can be overwritten from user space for
diagnostic, but we need some working default values.
Should I integrate this comment in to the yaml?
Regards,
Oleksij
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next prev parent reply other threads:[~2021-03-29 13:07 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-29 7:31 [PATCH v5 0/3] mainline ti tsc2046 adc driver Oleksij Rempel
2021-03-29 7:31 ` [PATCH v5 1/3] dt-bindings:iio:adc: add generic settling-time-us and oversampling-ratio channel properties Oleksij Rempel
2021-03-29 10:25 ` Jonathan Cameron
2021-03-29 13:06 ` Oleksij Rempel [this message]
2021-03-29 15:21 ` Jonathan Cameron
2021-03-29 7:31 ` [PATCH v5 2/3] dt-bindings:iio:adc: add documentation for TI TSC2046 controller Oleksij Rempel
2021-03-29 7:31 ` [PATCH v5 3/3] iio: adc: add ADC driver for the " Oleksij Rempel
2021-03-29 10:58 ` Jonathan Cameron
2021-04-13 9:31 ` [Ping for Dmitry] " Oleksij Rempel
2021-04-15 4:58 ` Dmitry Torokhov
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