From mboxrd@z Thu Jan 1 00:00:00 1970 From: fabrice.gasnier@st.com (Fabrice Gasnier) Date: Mon, 24 Jul 2017 18:10:39 +0200 Subject: [PATCH v2 2/3] dt-bindings: iio: adc: stm32: add optional st, min-sample-time-nsecs In-Reply-To: <1500912640-23927-1-git-send-email-fabrice.gasnier@st.com> References: <1500912640-23927-1-git-send-email-fabrice.gasnier@st.com> Message-ID: <1500912640-23927-3-git-send-email-fabrice.gasnier@st.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 'st,min-sample-time-nsecs' property so this can be tuned in dt. Signed-off-by: Fabrice Gasnier --- Changes in v2: - Use 'st,min-sample-time-nsecs' instead of 'min-sample-time'. --- 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..48bfcaa3 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. +- st,min-sample-time-nsecs: 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 { -- 1.9.1