IIO: Add DT bindings for sigma delta adc modulator

Add documentation of device tree bindings to support
sigma delta modulator in IIO framework.

Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@st.com>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/Documentation/devicetree/bindings/iio/adc/sigma-delta-modulator.txt b/Documentation/devicetree/bindings/iio/adc/sigma-delta-modulator.txt
new file mode 100644 (file)
index 0000000..e9ebb8a
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/adc/sigma-delta-modulator.txt
@@ -0,0 +1,13 @@
+Device-Tree bindings for sigma delta modulator
+
+Required properties:
+- compatible: should be "ads1201", "sd-modulator". "sd-modulator" can be use
+       as a generic SD modulator if modulator not specified in compatible list.
+- #io-channel-cells = <1>: See the IIO bindings section "IIO consumers".
+
+Example node:
+
+       ads1202: adc@0 {
+               compatible = "sd-modulator";
+               #io-channel-cells = <1>;
+       };