Merge 'BLE from Linux'

See merge request !376

Documentation/bluetooth/card10.rst

@@ -185,3 +185,31 @@ The light sensor characteristic makes it possible to read the current value of t
 The range of this sensor is between 0 (``0x0``) and 400 (``0x9001``).
 
 - reading of ``0x0e00`` means **14**
+
+Access via btgatt-client
+---------------------------------
+
+Accessing services from a linux system is possible via ``btgatt-client``. The inbuilt gatt client of ``bluetoothctl`` as well as ``libgatt`` were tested, but struggled with the card10's BLE stack.
+
+**Example**:
+
+.. code-block::
+
+    # pairing the card10:
+    
+    $ bluetoothctl
+    [bluetooth]# power on
+    [bluetooth]# scan on
+    [bluetooth]# pair CA:4D:10:xx:xx:xx     #replace xx:xx:xx with scan result
+    # if this query doesn't appear, remove and re-pair:
+    [agent] Confirm passkey ###### (yes/no): [CHG] Device CA:4D:10:xx:xx:xx Name: card10
+    [card10-xxxxxx]# disconnect CA:4D:10:xx:xx:xx
+
+    # using a service:
+
+    $ btgatt-client -d CA:4D:10:xx:xx:xx
+    # wait until services have been discovered, may take a minute
+    [GATT client]# write-value 0x0926 31 31 31
+
+    # if this error appears remove and re-pair:
+    [GATT client]# Device disconnected: Software caused connection abort