Re: [PATCH 2/3] dt-bindings: iio: adc: stm32: add optional min-sample-time

[Jonathan Cameron <jic23-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>]

On Tue, 18 Jul 2017 14:35:31 +0200
Fabrice Gasnier <fabrice.gasnier-qxv4g6HH51o@public.gmane.org> wrote:

> STM32 ADC allows each channel to be sampled with a different sampling
> time. There's an application note that deals with this: 'How to get
> the best ADC accuracy in STM32...' It basically depends on analog input
> signal electrical properties (depends on board).
> 
> Add optional 'min-sample-time' property so this can be tuned in dt.
> 
> Signed-off-by: Fabrice Gasnier <fabrice.gasnier-qxv4g6HH51o@public.gmane.org>

This isn't yet very standard, so I think it needs a manufacturer
prefix, e.g. st,min-sample-time.  Also convention is I believe
to include the units as part of the naming where appropriate.

Hence st,min-sample-time-nsecs

Otherwise, seems good to me.

Jonathan
> ---
>  Documentation/devicetree/bindings/iio/adc/st,stm32-adc.txt | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/iio/adc/st,stm32-adc.txt b/Documentation/devicetree/bindings/iio/adc/st,stm32-adc.txt
> index 8310073..9cd964b 100644
> --- a/Documentation/devicetree/bindings/iio/adc/st,stm32-adc.txt
> +++ b/Documentation/devicetree/bindings/iio/adc/st,stm32-adc.txt
> @@ -74,6 +74,11 @@ Optional properties:
>    * can be 6, 8, 10 or 12 on stm32f4
>    * can be 8, 10, 12, 14 or 16 on stm32h7
>    Default is maximum resolution if unset.
> +- min-sample-time: Minimum sampling time in nanoseconds.
> +  Depending on hardware (board) e.g. high/low analog input source impedance,
> +  fine tune of ADC sampling time may be recommended.
> +  This can be either one value or an array that matches 'st,adc-channels' list,
> +  to set sample time resp. for all channels, or independently for each channel.
>  
>  Example:
>  	adc: adc@40012000 {