drm/connector: Add support for out-of-band hotplug notification (v3)
Add a new drm_connector_oob_hotplug_event() function and
oob_hotplug_event drm_connector_funcs member.
On some hardware a hotplug event notification may come from outside the
display driver / device. An example of this is some USB Type-C setups
where the hardware muxes the DisplayPort data and aux-lines but does
not pass the altmode HPD status bit to the GPU's DP HPD pin.
In cases like this the new drm_connector_oob_hotplug_event() function can
be used to report these out-of-band events.
Changes in v2:
- Make drm_connector_oob_hotplug_event() take a fwnode as argument and
have it call drm_connector_find_by_fwnode() internally. This allows
making drm_connector_find_by_fwnode() a drm-internal function and
avoids code outside the drm subsystem potentially holding on the
a drm_connector reference for a longer period.
Changes in v3:
- Drop the data argument to the drm_connector_oob_hotplug_event
function since it is not used atm. This can be re-added later when
a use for it actually arises.
Tested-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Link: https://lore.kernel.org/r/20210817215201.795062-5-hdegoede@redhat.com