summaryrefslogtreecommitdiff
path: root/drivers/usb/common/roles.c
AgeCommit message (Collapse)Author
2018-12-17usb: roles: Add a description for the class to KconfigHeikki Krogerus
That makes the USB role switch support option visible and selectable for the user. The class driver is also moved to drivers/usb/roles/ directory. This will fix an issue that we have with the Intel USB role switch driver on systems that don't have USB Type-C connectors: Intel USB role switch driver depends on the USB role switch class as it should, but since there was no way for the user to enable the USB role switch class, there was also no way to select that driver. USB Type-C drivers select the USB role switch class which makes the Intel USB role switch driver available and therefore hides the problem. So in practice Intel USB role switch driver was depending on USB Type-C drivers. Fixes: f6fb9ec02be1 ("usb: roles: Add Intel xHCI USB role switch driver") Cc: <stable@vger.kernel.org> Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-20usb: roles: Take care of driver module reference countingHeikki Krogerus
This fixes potential "BUG: unable to handle kernel paging request at ..." from happening. Fixes: fde0aa6c175a ("usb: common: Small class for USB role switches") Cc: <stable@vger.kernel.org> Acked-by: Hans de Goede <hdegoede@redhat.com> Tested-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-03-22usb: common: Small class for USB role switchesHeikki Krogerus
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>