iio: ti-ads8688: Add DT binding documentation

Adding binding documentation for Texas Instruments ADS8688 ADC.

Signed-off-by: Sean Nyekjaer <sean.nyekjaer@prevas.dk>
Reviewed-by: Martin Hundebøll <martin.hundeboll@prevas.dk>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

diff --git a/Documentation/devicetree/bindings/iio/adc/ti-ads8688.txt b/Documentation/devicetree/bindings/iio/adc/ti-ads8688.txt
new file mode 100644 (file)
index 0000000..a02337d
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+++ b/Documentation/devicetree/bindings/iio/adc/ti-ads8688.txt
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+* Texas Instruments' ADS8684 and ADS8688 ADC chip
+
+Required properties:
+ - compatible: Should be "ti,ads8684" or "ti,ads8688"
+ - reg: spi chip select number for the device
+
+Recommended properties:
+ - spi-max-frequency: Definition as per
+               Documentation/devicetree/bindings/spi/spi-bus.txt
+
+Optional properties:
+ - vref-supply: The regulator supply for ADC reference voltage
+
+Example:
+adc@0 {
+       compatible = "ti,ads8688";
+       reg = <0>;
+       vref-supply = <&vdd_supply>;
+       spi-max-frequency = <1000000>;
+};