diff options
| author | Heikki Krogerus <heikki.krogerus@linux.intel.com> | 2018-03-20 15:57:04 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-03-22 13:40:10 +0100 |
| commit | fde0aa6c175a4d8aa19e82b86ae0f9278bc8563b (patch) | |
| tree | 3fc526a1e5440059b25bbbac42deed590a7f3114 /Documentation/ABI | |
| parent | bdecb33af34f79cbfbb656661210f77c8b8b5b5f (diff) | |
usb: common: Small class for USB role switches
USB role switch is a device that can be used to choose the
data role for USB connector. With dual-role capable USB
controllers, the controller itself will be the switch, but
on some platforms the USB host and device controllers are
separate IPs and there is a mux between them and the
connector. On those platforms the mux driver will need to
register the switch.
With USB Type-C connectors, the host-to-device relationship
is negotiated over the Configuration Channel (CC). That
means the USB Type-C drivers need to be in control of the
role switch. The class provides a simple API for the USB
Type-C drivers for the control.
For other types of USB connectors (mainly microAB) the class
provides user space control via sysfs attribute file that
can be used to request role swapping from the switch.
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation/ABI')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-class-usb_role | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-class-usb_role b/Documentation/ABI/testing/sysfs-class-usb_role new file mode 100644 index 000000000000..3b810a425a52 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-class-usb_role @@ -0,0 +1,21 @@ +What: /sys/class/usb_role/ +Date: Jan 2018 +Contact: Heikki Krogerus <heikki.krogerus@linux.intel.com> +Description: + Place in sysfs for USB Role Switches. USB Role Switch is a + device that can select the data role (host or device) for USB + port. + +What: /sys/class/usb_role/<switch>/role +Date: Jan 2018 +Contact: Heikki Krogerus <heikki.krogerus@linux.intel.com> +Description: + The current role of the switch. This attribute can be used for + requesting role swapping with non-USB Type-C ports. With USB + Type-C ports, the ABI defined for USB Type-C connector class + must be used. + + Valid values: + - none + - host + - device |