gen2: add README for usbgadget

Change-Id: If629ee6edf7a24dd582f3c34a12dea76b84d7388
Signed-off-by: Yannick Gicquel <yannick.gicquel@iot.bzh>

1 files changed, 57 insertions, 0 deletions

diff --git a/meta-rcar-gen2/README-usbgadget.md b/meta-rcar-gen2/README-usbgadget.md
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+USB Gadget
+==========
+
+# Introduction
+
+This README describes a way the USB Gadget feature can be used on Renesas Porter boards.
+
+## Hardware setup
+
+To use the USB Gadget feature, you need an extra micro-USB cable.
+The proposed setup is based on the selection of USB OTG feature by configuring the jumper JP13 between 1-2 ("Host"). Then, you can plug the cable in CN22 connector ("USB Channel 0").
+
+## Software setup
+
+Be sure you have the "usbgadget" feature in the DISTRO_FEATURES bitbake environment variable.
+
+# Usage
+
+## Manual configuration
+
+Example to uses Ethernet over USB feature:
+
+    # modprobe g_ether
+    # ip a | grep -A 2 usb0
+    5: usb0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
+        link/ether 4e:bc:d4:ab:7e:e5 brd ff:ff:ff:ff:ff:ff
+    # ip address add 192.168.0.10 dev usb0
+
+Now, from your host computer you can check connectivity:
+
+    $ ping 192.168.0.10
+    PING 192.168.0.10 (192.168.0.10) 56(84) bytes of data.
+    64 bytes from 192.168.0.10: icmp_seq=1 ttl=64 time=0.370 ms
+    64 bytes from 192.168.0.10: icmp_seq=2 ttl=64 time=0.406 ms
+    ...
+
+## Persistent configuration
+
+We can load the module at startup, by creating a file `/etc/modules-load.d/g_ether.conf`.
+
+The file content should be as below:
+
+    # Load g_ether at boot
+    g_ether
+
+Connman can handle the Ethernet over USB link. First, we create the directory which
+contain the configuration file:
+
+    # mkdir /etc/connman
+
+Then we can edit a `/etc/connman/main.conf` file:
+
+    [General]
+    PreferredTechnologies=ethernet,wifi,cellular
+    PersistentTetheringMode=true
+    TetheringTechnologies=gadget
+