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+ADC device binding
+
+There are no mandatory properties for ADC. However, if Voltage info is required,
+then there are two options:
+- use microvolts constraint or
+- use regulator phandle to enable/read supply's Voltage
+
+Properties and constraints:
+*optional and always checked, Voltage polarity info:
+- vdd-polarity-negative: positive reference Voltage has a negative polarity
+- vss-polarity-negative: negative reference Voltage has a negative polarity
+
+Chose one option, for each supply (Vdd/Vss):
+
+*optional and always checked, supply Voltage constants:
+- vdd-supply: phandle to Vdd regulator's node
+- vss-supply: phandle to Vss regulator's node
+
+*optional and checked only if the above corresponding, doesn't exist:
+- vdd-microvolts: positive reference Voltage value [uV]
+- vss-microvolts: negative reference Voltage value [uV]
+
+Example with constant 'Vdd' value:
+adc@1000000 {
+ compatible = "some-adc";
+ reg = <0xaabb000 0x100>;
+ status = "enabled";
+ vdd-microvolts = <1800000>;
+};
+
+Example of supply phandle usage, for the ADC's VDD/VSS references as below:
+ _______ _______
+ |Sandbox| |Sandbox|
+ : PMIC : : ADC :
+ . . . .
+ | | (Vdd) | AIN0|-->
+ | BUCK2|-------|VDDref |
+ | (3.3V)| _|VSSref |
+ |_______| | |_______|
+ _|_
+
+For the above PMIC, the node can be defined as follows:
+sandbox_pmic {
+ compatible = "sandbox,pmic";
+ ...
+ buck2: buck2 {
+ regulator-name = "SUPPLY_3.3V";
+ regulator-min-microvolt = <3300000>;
+ regulator-max-microvolt = <3300000>;
+ };
+ ...
+};
+
+For the above ADC, the node can be defined as follows:
+adc@0 {
+ compatible = "sandbox,adc";
+ vdd-supply = <&buck2>;
+ vss-microvolts = <0>;
+};
+
+The ADC uclass code, will enable the supply before start of the conversion,
+but it will not configure the regulator settings.