[PATCH v4 01/10] dt-bindings: adc: add excitation-current-chopping property

[Kurt Borja <kuurtb@gmail.com>]

Add a generic excitation-current-chopping property. This is a feature
seen frequently in ADCs that are designed to ratiometrically measure
resistive loads, such as RTDs and strain gauges. Enabling this can
reduce any error due to excitation current mismatch by swapping
excitation sources of alternate conversions. This can have side-effects
in timing and filter response, so it is not always desirable to enable
this feature in some applications. Therefore, it is best to make this a
property that can be enabled or disabled in the device tree.

Suggested-by: David Lechner <dlechner@baylibre.com>
Signed-off-by: Kurt Borja <kuurtb@gmail.com>
---
 Documentation/devicetree/bindings/iio/adc/adc.yaml | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/Documentation/devicetree/bindings/iio/adc/adc.yaml b/Documentation/devicetree/bindings/iio/adc/adc.yaml
index b673eaa5d072..fe20aa8f1bfc 100644
--- a/Documentation/devicetree/bindings/iio/adc/adc.yaml
+++ b/Documentation/devicetree/bindings/iio/adc/adc.yaml
@@ -109,6 +109,14 @@ properties:
       sources. The index in the array corresponds to the same index in the
       excitation-channels array.
 
+  excitation-current-chopping:
+    type: boolean
+    description:
+      If set, the excitation current sources are swapped and averaged on every
+      other conversion to reduce current mismatch. This generally comes at the
+      expense of added settling time between conversions, so should be omitted
+      on systems with high-frequency signals or high data rate requirements.
+
   burn-out-current-nanoamp:
     description:
       Burn-out current sources provide current to the channel's input pins for

-- 
2.55.0