usb: typec: Make bus switch code retimer-aware

Since ports can have retimers associated with them, update the Type-C
alternate mode bus code to also set retimer state when the switch state
is updated.

While we are here, make the typec_retimer_dev_type declaration in the
retimer.h file as extern, so that the header file can be successfully
included in the bus code without redeclaration compilation errors.

Signed-off-by: Prashant Malani <pmalani@chromium.org>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20230112221609.540754-4-pmalani@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: typec: retimer: Use device type for matching

Device name is not reliable so using the type instead in
retimer_fwnode_match().

This will also introduce is_typec_retimer() helper, and
remove the static keyword from the retimer device type. That
will make it accessible also in the main typec class.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20221019145552.32493-1-heikki.krogerus@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

usb: typec: Add support for retimers

Introduce a retimer device class and associated functions that register
and use retimer "switch" devices. These operate in a manner similar to
the "mode-switch" and help configure retimers that exist between the
Type-C connector and host controller(s).

Type C ports can be linked to retimers using firmware node device
references (again, in a manner similar to "mode-switch").

There are no new sysfs files being created; there is the new retimer
class directory, but there are no class-specific files being created
there.

Signed-off-by: Prashant Malani <pmalani@chromium.org>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20220711072333.2064341-2-pmalani@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>