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@xxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxx> > > --- > > 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 -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
