@@ -6010,6 +6010,22 @@ static bool drm_dp_mst_is_virtual_dpcd(struct drm_dp_mst_port *port)
return false;
}
+/**
+ * drm_dp_mst_aux_for_parent() - Get the AUX device for an MST port's parent
+ * @port: MST port whose parent's AUX device is returned
+ *
+ * Return the AUX device for @port's parent or NULL if port's parent is the
+ * root port.
+ */
+struct drm_dp_aux *drm_dp_mst_aux_for_parent(struct drm_dp_mst_port *port)
+{
+ if (!port->parent || !port->parent->port_parent)
+ return NULL;
+
+ return &port->parent->port_parent->aux;
+}
+EXPORT_SYMBOL(drm_dp_mst_aux_for_parent);
+
/**
* drm_dp_mst_dsc_aux_for_port() - Find the correct aux for DSC
* @port: The port to check. A leaf of the MST tree with an attached display.
@@ -954,6 +954,7 @@ bool drm_dp_mst_port_is_logical(struct drm_dp_mst_port *port)
return port->port_num >= DP_MST_LOGICAL_PORT_0;
}
+struct drm_dp_aux *drm_dp_mst_aux_for_parent(struct drm_dp_mst_port *port);
struct drm_dp_aux *drm_dp_mst_dsc_aux_for_port(struct drm_dp_mst_port *port);
static inline struct drm_dp_mst_topology_state *