diff options
Diffstat (limited to 'Documentation/usb/functionfs.txt')
| -rw-r--r-- | Documentation/usb/functionfs.txt | 17 |
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. - |