thunderbolt: Introduce tb_xdomain_downstream_port()

In the same way we did for the routers add a function that returns the
parent routers downstream facing port for XDomain devices.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h
index a8e1725b4cb5..1e617c6e11ae 100644
--- a/drivers/thunderbolt/tb.h
+++ b/drivers/thunderbolt/tb.h
@@ -1197,6 +1197,17 @@ static inline struct tb_switch *tb_xdomain_parent(struct tb_xdomain *xd)
 	return tb_to_switch(xd->dev.parent);
 }
 
+/**
+ * tb_xdomain_downstream_port() - Return downstream facing port of parent router
+ * @xd: Xdomain pointer
+ *
+ * Returns the downstream port the XDomain is connected to.
+ */
+static inline struct tb_port *tb_xdomain_downstream_port(struct tb_xdomain *xd)
+{
+	return tb_port_at(xd->route, tb_xdomain_parent(xd));
+}
+
 int tb_retimer_nvm_read(struct tb_retimer *rt, unsigned int address, void *buf,
 			size_t size);
 int tb_retimer_scan(struct tb_port *port, bool add);