Describe the properties used for shared boost configuration.
Based on David Rhodes shared boost patches.

Signed-off-by: Lucas Tanure <lucas.tanure@collabora.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
---
 .../devicetree/bindings/sound/cirrus,cs35l41.yaml      | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/sound/cirrus,cs35l41.yaml b/Documentation/devicetree/bindings/sound/cirrus,cs35l41.yaml
index 18fb471aa891..14dea1feefc5 100644
--- a/Documentation/devicetree/bindings/sound/cirrus,cs35l41.yaml
+++ b/Documentation/devicetree/bindings/sound/cirrus,cs35l41.yaml
@@ -85,11 +85,19 @@ properties:
       boost-cap-microfarad.
       External Boost must have GPIO1 as GPIO output. GPIO1 will be set high to
       enable boost voltage.
+      Shared boost allows two amplifiers to share a single boost circuit by
+      communicating on the MDSYNC bus. The active amplifier controls the boost
+      circuit using combined data from both amplifiers. GPIO1 should be
+      configured for Sync when shared boost is used. Shared boost is not
+      compatible with External boost. Active amplifier requires
+      boost-peak-milliamp, boost-ind-nanohenry and boost-cap-microfarad.
       0 = Internal Boost
       1 = External Boost
+      2 = Shared Boost Active
+      3 = Shared Boost Passive
     $ref: /schemas/types.yaml#/definitions/uint32
     minimum: 0
-    maximum: 1
+    maximum: 3
 
   cirrus,gpio1-polarity-invert:
     description:
-- 
2.39.2