Documentation: usb: SERIAL function testing
Summary of how to test SERIAL function of USB gadget.
Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
diff --git a/Documentation/usb/gadget-testing.txt b/Documentation/usb/gadget-testing.txt
index 61bc5f5..bc57c65 100644
--- a/Documentation/usb/gadget-testing.txt
+++ b/Documentation/usb/gadget-testing.txt
@@ -14,6 +14,7 @@
11. OBEX function
12. PHONET function
13. RNDIS function
+14. SERIAL function
1. ACM function
@@ -529,3 +530,33 @@
On the device: ping <host's IP>
On the host: ping <device's IP>
+
+14. SERIAL function
+===================
+
+The function is provided by usb_f_gser.ko module.
+
+Function-specific configfs interface
+------------------------------------
+
+The function name to use when creating the function directory is "gser".
+The SERIAL function provides just one attribute in its function directory:
+
+ port_num
+
+The attribute is read-only.
+
+There can be at most 4 ACM/generic serial/OBEX ports in the system.
+
+Testing the SERIAL function
+---------------------------
+
+On host: insmod usbserial
+ echo VID PID >/sys/bus/usb-serial/drivers/generic/new_id
+On host: cat > /dev/ttyUSB<X>
+On target: cat /dev/ttyGS<Y>
+
+then the other way round
+
+On target: cat > /dev/ttyGS<Y>
+On host: cat /dev/ttyUSB<X>
