doc: Add EchoCancelingNoiseReduction to Handsfree

This patch adds echo canceling and noise reduction property to Handsfree
interface, allowing the handsfree unit to disable this feature in the
audio gateway. The HFP spec defines the procedure to turn off echo
canceling and noise reduction only, it is not allowed to enable this
feature from the HF unit.

According to Bluetooth HFP 1.6 spec: By default, if the AG supports its
own embedded echo canceling and/or noise reduction functions, it shall
have them activated until the AT+NREC command is received from the HF
unit. From then on, and until the current Service Level Connection is
dropped for any reason, the AG shall disable these functions every time
an Audio Connection is established.

diff --git a/doc/handsfree-api.txt b/doc/handsfree-api.txt
index 0b5d4215301b2bef49db1060f54156e9661ca737..d6ffca5711d568ed0ee6a0541f4415e90a9f92e6 100644 (file)
--- a/doc/handsfree-api.txt
+++ b/doc/handsfree-api.txt
@@ -44,6 +44,7 @@ Properties    array{string} Features [readonly]
                        supported values are:
                                "voice-recognition"
                                "attach-voice-tag"
+                               "echo-canceling-and-noise-reduction"
 
                boolean InbandRinging [readonly]
 
@@ -56,6 +57,15 @@ Properties   array{string} Features [readonly]
                        to activate or deactivate the function from the HF, or
                        the AG could autonomously initiate it.
 
+               boolean EchoCancelingNoiseReduction [readwrite]
+
+                       Non-persistent Boolean property representing whether
+                       echo canceling and noise reduction is enabled in the
+                       AG. This feature can only be disabled once from the
+                       HF unit; the current specification does not allow the
+                       HF unit from enabling this feature on the AG once
+                       it has been disabled.
+
                byte BatteryChargeLevel [readonly]
 
                        The current charge level of the battery.  The value