[PATCH v9 2/3] drm/bridge: add a .destroy func

[Luca Ceresoli <luca.ceresoli@bootlin.com>]

Some users of DRM bridges may need to execute specific code just before
deallocation.

As of now the only known user would be KUnit tests.

Suggested-by: Maxime Ripard <mripard@kernel.org>
Acked-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
---

Changes in v9:
- move .destroy before .detach in struct drm_bridge_funcs declaration for
  alphabetic ordering
- Add Maxime's Acked-by
- Fix typo in commit message

This patch was added in v8. The .destroy callback had appeared in v5 as
well [5], but as part of a larger patch and for different reasons that do
not apply anymore.

[5] https://lore.kernel.org/all/20241231-hotplug-drm-bridge-v5-3-173065a1ece1@bootlin.com/#t
---
 drivers/gpu/drm/drm_bridge.c |  2 ++
 include/drm/drm_bridge.h     | 10 ++++++++++
 2 files changed, 12 insertions(+)

diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
index d0e81639927a73422671b7b43f3e8a946f1d4300..bf34cc5ab0316889186ddf5ebb3a984b09eeb86c 100644
--- a/drivers/gpu/drm/drm_bridge.c
+++ b/drivers/gpu/drm/drm_bridge.c
@@ -203,6 +203,8 @@ static void __drm_bridge_free(struct kref *kref)
 {
 	struct drm_bridge *bridge = container_of(kref, struct drm_bridge, refcount);
 
+	if (bridge->funcs->destroy)
+		bridge->funcs->destroy(bridge);
 	kfree(bridge->container);
 }
 
diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
index 0af5db244db8580ea0c9af1d9a373b7bf62ee699..dbd6503f33ba917fbcfb73b985d9c34910f04e0f 100644
--- a/include/drm/drm_bridge.h
+++ b/include/drm/drm_bridge.h
@@ -77,6 +77,16 @@ struct drm_bridge_funcs {
 	int (*attach)(struct drm_bridge *bridge, struct drm_encoder *encoder,
 		      enum drm_bridge_attach_flags flags);
 
+	/**
+	 * @destroy:
+	 *
+	 * This callback is invoked when the bridge is about to be
+	 * deallocated.
+	 *
+	 * The @destroy callback is optional.
+	 */
+	void (*destroy)(struct drm_bridge *bridge);
+
 	/**
 	 * @detach:
 	 *

-- 
2.49.0