drm/bridge: samsung-dsim: samsung_dsim_host_attach: convert to of_drm_find_and_get_bridge()

of_drm_find_bridge() is deprecated. Move to its replacement
of_drm_find_and_get_bridge() which gets a bridge reference, and ensure it
is put when done. Also switch to the drm_bridge::next_bridge pointer.

This needs to handle both cases: when of_drm_find_panel() succeeds and when
it fails.

In the 'else' case (i.e. when of_drm_find_panel() fails), just switch to
of_drm_find_and_get_bridge() to ensure the bridge is not freed while in use
in the function tail, when it is stored in dsi->bridge.next_bridge.

In the 'then' case (i.e. when of_drm_find_panel() succeeds),
devm_drm_panel_bridge_add() already increments the refcount using devres
which ties the bridge allocation lifetime to the device lifetime, so we
would not need to do anything. However to have the same behaviour in both
branches take an additional reference here, so that the bridge needs to be
put whichever branch is taken without more complicated logic. Ensure to
clear the bridge pointer however, to avoid calling drm_bridge_put() on an
ERR_PTR.

Acked-by: Maxime Ripard <mripard@kernel.org>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://patch.msgid.link/20260109-drm-bridge-alloc-getput-drm_of_find_bridge-2-v2-12-8bad3ef90b9f@bootlin.com
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>

1 files changed, 0 insertions, 1 deletions

diff --git a/include/drm/bridge/samsung-dsim.h b/include/drm/bridge/samsung-dsim.h
index 31d7ed589233..03005e474704 100644
--- a/include/drm/bridge/samsung-dsim.h
+++ b/include/drm/bridge/samsung-dsim.h
@@ -100,7 +100,6 @@ struct samsung_dsim_plat_data {
 struct samsung_dsim {
 	struct mipi_dsi_host dsi_host;
 	struct drm_bridge bridge;
-	struct drm_bridge *out_bridge;
 	struct device *dev;
 	struct drm_display_mode mode;