net: qmi_wwan: document the qmi/raw_ip sysfs file

Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/Documentation/ABI/testing/sysfs-class-net-qmi b/Documentation/ABI/testing/sysfs-class-net-qmi
new file mode 100644 (file)
index 0000000..fa5a00b
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-net-qmi
@@ -0,0 +1,23 @@
+What:          /sys/class/net/<iface>/qmi/raw_ip
+Date:          Dec 2015
+KernelVersion: 4.4
+Contact:       Bjørn Mork <bjorn@mork.no>
+Description:
+               Boolean.  Default: 'N'
+
+               Set this to 'Y' to change the network device link
+               framing from '802.3' to 'raw-ip'.
+
+               The netdev will change to reflect the link framing
+               mode.  The netdev is an ordinary ethernet device in
+               '802.3' mode, and the driver expects to exchange
+               frames with an ethernet header over the USB link. The
+               netdev is a headerless p-t-p device in 'raw-ip' mode,
+               and the driver expects to echange IPv4 or IPv6 packets
+               without any L2 header over the USB link.
+
+               Userspace is in full control of firmware configuration
+               through the delegation of the QMI protocol. Userspace
+               is responsible for coordination of driver and firmware
+               link framing mode, changing this setting to 'Y' if the
+               firmware is configured for 'raw-ip' mode.