drm/bridge: add devm_drm_put_bridge()

Bridges obtained via devm_drm_bridge_alloc(dev, ...) will be put when the
requesting device (@dev) is removed.

However drivers which obtained them may need to put the obtained reference
explicitly. One such case is if they bind the devm removal action to a
different device than the one implemented by the driver itself and which
might be removed at a different time, such as bridge/panel.c.

Add devm_drm_put_bridge() to manually release a devm-obtained bridge in
such cases.

This function is considered only a temporary workaround until the panel
bridge is reworked and should be removed afterwards.

Acked-by: Maxime Ripard <mripard@kernel.org>
Link: https://lore.kernel.org/r/20250509-drm-bridge-convert-to-alloc-api-v3-20-b8bc1f16d7aa@bootlin.com
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
index b4c89ec01998..d0e81639927a 100644
--- a/drivers/gpu/drm/drm_bridge.c
+++ b/drivers/gpu/drm/drm_bridge.c
@@ -1392,6 +1392,23 @@ struct drm_bridge *of_drm_find_bridge(struct device_node *np)
 EXPORT_SYMBOL(of_drm_find_bridge);
 #endif
 
+/**
+ * devm_drm_put_bridge - Release a bridge reference obtained via devm
+ * @dev: device that got the bridge via devm
+ * @bridge: pointer to a struct drm_bridge obtained via devm
+ *
+ * Same as drm_bridge_put() for bridge pointers obtained via devm functions
+ * such as devm_drm_bridge_alloc().
+ *
+ * This function is a temporary workaround and MUST NOT be used. Manual
+ * handling of bridge lifetime is inherently unsafe.
+ */
+void devm_drm_put_bridge(struct device *dev, struct drm_bridge *bridge)
+{
+	devm_release_action(dev, drm_bridge_put_void, bridge);
+}
+EXPORT_SYMBOL(devm_drm_put_bridge);
+
 static void drm_bridge_debugfs_show_bridge(struct drm_printer *p,
 					   struct drm_bridge *bridge,
 					   unsigned int idx)