[PATCH v5 7/9] dt-bindings: iio: adc: document diff-channels corner case for some ADCs

[Alexandru Ardelean <aardelean@baylibre.com>]

Some ADCs have channels with negative and positive inputs, which can be
used to measure differential voltage levels. These inputs/pins are
dedicated (to the given channel) and cannot be muxed as with other ADCs.

For those types of setups, the 'diff-channels' property can be specified to
be used with the channel number (or reg property) for both negative and
positive inputs/pins.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Alexandru Ardelean <aardelean@baylibre.com>
---
 Documentation/devicetree/bindings/iio/adc/adc.yaml | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Documentation/devicetree/bindings/iio/adc/adc.yaml b/Documentation/devicetree/bindings/iio/adc/adc.yaml
index 8e7835cf36fd..b9bc02b5b07a 100644
--- a/Documentation/devicetree/bindings/iio/adc/adc.yaml
+++ b/Documentation/devicetree/bindings/iio/adc/adc.yaml
@@ -37,6 +37,10 @@ properties:
       to both the positive and negative inputs of a differential ADC.
       The first value specifies the positive input pin, the second
       specifies the negative input pin.
+      There are also some ADCs, where the differential channel has dedicated
+      positive and negative inputs which can be used to measure differential
+      voltage levels. For those setups, this property can be configured with
+      the 'reg' property for both inputs (i.e. diff-channels = <reg reg>).
 
   single-channel:
     $ref: /schemas/types.yaml#/definitions/uint32
-- 
2.46.0