Adding documentation for adaq4370-4 and adaq4380-4 supported devices. In
particular, document the reference voltage mechanism and the gain
parameter that are specific to adaq devices.

Signed-off-by: Julien Stephan <jstephan@baylibre.com>
---
 Documentation/iio/ad7380.rst | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/Documentation/iio/ad7380.rst b/Documentation/iio/ad7380.rst
index 6f70b49b9ef27c1ac32acaefecd1146e5c8bd6cc..ae408ff2fa9c97427a9fef57020fb54203d2d33e 100644
--- a/Documentation/iio/ad7380.rst
+++ b/Documentation/iio/ad7380.rst
@@ -27,6 +27,8 @@ The following chips are supported by this driver:
 * `AD7386-4 <https://www.analog.com/en/products/ad7386-4.html>`_
 * `AD7387-4 <https://www.analog.com/en/products/ad7387-4.html>`_
 * `AD7388-4 <https://www.analog.com/en/products/ad7388-4.html>`_
+* `ADAQ4370-4 <https://www.analog.com/en/products/adaq4370-4.html>`_
+* `ADAQ4380-4 <https://www.analog.com/en/products/adaq4380-4.html>`_
 
 
 Supported features
@@ -47,6 +49,12 @@ ad7380-4
 ad7380-4 supports only an external reference voltage (2.5V to 3.3V). It must be
 declared in the device tree as ``refin-supply``.
 
+adaq devices
+~~~~~~~~~~~~
+
+adaq4370-4 and adaq4380-4 don't have an external reference, but use a 3V
+internal reference derived from one of its supplies (``refin-supply``)
+
 All other devices from ad738x family
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
@@ -121,6 +129,16 @@ Example for AD7386/7/8 (2 channels parts):
 
 When enabling sequencer mode, the effective sampling rate is divided by two.
 
+
+Gain (adaq devices only)
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+adaq devices have a pin selectable gain in front of each adc. The appropriate
+gain is selectable from device tree using the ``adi,gain-milli`` property.
+Refer to the typical connection diagrams section of the datasheet for pin
+wiring.
+
+
 Unimplemented features
 ----------------------
 

-- 
2.47.0