[PATCH 1/3] dt-bindings: iio: adc: stm32: add analog switches supply control

From: Fabrice Gasnier
Date: Wed Jun 12 2019 - 03:30:16 EST

On stm32h7 and stm32mp1, the ADC inputs are multiplexed with analog
switches which have reduced performances when their supply is below 2.7V
(vdda by default).

Add documentation for optional vdda-supply & vdd-supply that can be used
to supply analog circuitry (controlled by syscfg bits).

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@xxxxxx>
Documentation/devicetree/bindings/iio/adc/st,stm32-adc.txt | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/Documentation/devicetree/bindings/iio/adc/st,stm32-adc.txt b/Documentation/devicetree/bindings/iio/adc/st,stm32-adc.txt
index 8346bcb..3af48b9 100644
--- a/Documentation/devicetree/bindings/iio/adc/st,stm32-adc.txt
+++ b/Documentation/devicetree/bindings/iio/adc/st,stm32-adc.txt
@@ -46,6 +46,12 @@ Required properties:
Optional properties:
- A pinctrl state named "default" for each ADC channel may be defined to set
inX ADC pins in mode of operation for analog input on external pin.
+- vdda-supply: Phandle to the vdda input voltage. It can be used to supply ADC
+ analog inputs switches on stm32h7 and stm32mp1.
+- vdd-supply: Phandle to the vdd input voltage. It can be used to supply ADC
+ analog inputs switches on stm32mp1.
+- st,syscfg: Phandle to system configuration controller. It can be used to
+ control the analog circuitry on stm32h7 and stm32mp1.

Contents of a stm32 adc child node: