[PATCH 2/6] dt-bindings: iio: ad7949: Add adi,reference-select

[Adam Michaelis <adam.michaelis@xxxxxxxxxxxxxxxxxxx>]

Adding optional parameter to AD7949 to specify the source for the
reference voltage signal. Default value is maintaned with option '6' to
match previous version of driver.

Signed-off-by: Adam Michaelis <adam.michaelis@xxxxxxxxxxxxxxxxxxx>
---
 .../devicetree/bindings/iio/adc/ad7949.txt         | 22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/iio/adc/ad7949.txt b/Documentation/devicetree/bindings/iio/adc/ad7949.txt
index c7f5057356b1..14ee9a2cb2a5 100644
--- a/Documentation/devicetree/bindings/iio/adc/ad7949.txt
+++ b/Documentation/devicetree/bindings/iio/adc/ad7949.txt
@@ -6,11 +6,29 @@ Required properties:
 	* "adi,ad7682"
 	* "adi,ad7689"
  - reg: spi chip select number for the device
- - vref-supply: The regulator supply for ADC reference voltage
 
-Example:
+Optional properties:
+ - adi,reference-select: Select the reference voltage source to use
+ when converting the input voltages. Valid values are:
+   0: Internal 2.5V reference; temperature sensor enabled
+   1: Internal 4.096V reference; temperature sensor enabled
+   2: External reference, temperature sensor enabled, no buffer
+   3: External reference, temperature sensor enabled, buffer enabled
+   6: External reference, temperature sensor disabled, no buffer
+   7: External reference, temperature sensor disabled, buffer enabled
+ - vref-supply: The regulator supply for ADC reference voltage. Required
+ if external reference selected by 'adi,reference-select'.
+
+Examples:
 adc@0 {
 	compatible = "adi,ad7949";
 	reg = <0>;
+	adi,reference-select = <2>;
 	vref-supply = <&vdd_supply>;
 };
+
+adc@0 {
+	compatible = "adi,ad7949";
+	reg = <0>;
+	adi,reference-select = <0>;
+};
-- 
1.9.1