usb: typec: Block mode entry if the port has the mode disabled

Originally the port drivers were expected to check does the
connector have the mode enabled or disabled when the alt
mode drivers attempted to enter the mode, but since
typec_altmode_enter() puts the connector into USB Safe
State before calling the port driver, it really has to do
the check on its own, and before changing the state.
Otherwise the connector may be left in USB Safe State if the
port driver does not move it back to normal USB operation
when the mode is disabled.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20191230142611.24921-2-heikki.krogerus@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/typec/bus.c

@@ -101,6 +101,9 @@ int typec_altmode_enter(struct typec_altmode *adev)
 	if (!pdev->ops || !pdev->ops->enter)
 		return -EOPNOTSUPP;
 
+	if (is_typec_port(pdev->dev.parent) && !pdev->active)
+		return -EPERM;
+
 	/* Moving to USB Safe State */
 	ret = typec_altmode_set_state(adev, TYPEC_STATE_SAFE);
 	if (ret)