[PATCH 2/3] dt-bindings: iio: adc: stm32: add optional min-sample-time
From: jic23@kernel.org (Jonathan Cameron)
Date: 2017-07-23 10:53:45
Also in:
linux-devicetree, linux-iio, lkml
On Tue, 18 Jul 2017 14:35:31 +0200 Fabrice Gasnier [off-list ref] 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 <redacted>
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
quoted hunk ↗ jump to hunk
--- 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 at 40012000 {