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

[Fabrice Gasnier]

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:
 -----------------------------------
-- 
2.7.4