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-rw-r--r--Documentation/usb/functionfs.txt17
1 files changed, 9 insertions, 8 deletions
diff --git a/Documentation/usb/functionfs.txt b/Documentation/usb/functionfs.txt
index eaaaea019fc7..7fdc6d840ac5 100644
--- a/Documentation/usb/functionfs.txt
+++ b/Documentation/usb/functionfs.txt
@@ -1,4 +1,6 @@
-*How FunctionFS works*
+====================
+How FunctionFS works
+====================
From kernel point of view it is just a composite function with some
unique behaviour. It may be added to an USB configuration only after
@@ -38,13 +40,13 @@ when mounting.
One can imagine a gadget that has an Ethernet, MTP and HID interfaces
where the last two are implemented via FunctionFS. On user space
-level it would look like this:
+level it would look like this::
-$ insmod g_ffs.ko idVendor=<ID> iSerialNumber=<string> functions=mtp,hid
-$ mkdir /dev/ffs-mtp && mount -t functionfs mtp /dev/ffs-mtp
-$ ( cd /dev/ffs-mtp && mtp-daemon ) &
-$ mkdir /dev/ffs-hid && mount -t functionfs hid /dev/ffs-hid
-$ ( cd /dev/ffs-hid && hid-daemon ) &
+ $ insmod g_ffs.ko idVendor=<ID> iSerialNumber=<string> functions=mtp,hid
+ $ mkdir /dev/ffs-mtp && mount -t functionfs mtp /dev/ffs-mtp
+ $ ( cd /dev/ffs-mtp && mtp-daemon ) &
+ $ mkdir /dev/ffs-hid && mount -t functionfs hid /dev/ffs-hid
+ $ ( cd /dev/ffs-hid && hid-daemon ) &
On kernel level the gadget checks ffs_data->dev_name to identify
whether it's FunctionFS designed for MTP ("mtp") or HID ("hid").
@@ -64,4 +66,3 @@ have been written to their ep0's.
Conversely, the gadget is unregistered after the first USB function
closes its endpoints.
-