From 03d1078112fddd706b2c1e4a7d98cf18700eb5df Mon Sep 17 00:00:00 2001 From: Luca Ceresoli Date: Mon, 11 May 2026 18:40:06 +0200 Subject: drm/bridge: add of_drm_get_bridge_by_endpoint() drm_of_find_panel_or_bridge() is widely used, but many callers pass NULL into the @panel or the @bridge arguments, thus making a very partial usage of this rather complex function. Besides, the bridge returned in @bridge is not refcounted, thus making this API unsafe when DRM bridge hotplug will be introduced. Solve both issues for the cases of calls to drm_of_find_panel_or_bridge() with a NULL @panel pointer by adding a new function that only looks for bridges (and is thus much simpler) and increments the refcount of the returned bridge. The new function is identical to drm_of_find_panel_or_bridge() except it: - handles bridge refcounting: uses of_drm_find_and_get_bridge() instead of of_drm_find_bridge() internally to return a refcounted bridge - is simpler to use: just takes no @panel parameter, returns the pointer in the return value instead of a double pointer argument - has a simpler implementation: it is equal to drm_of_find_panel_or_bridge() after removing the code that becomes dead when @panel == NULL Also add this function to drm_bridge.c and not drm_of.c because it returns bridges only. Reviewed-by: Dmitry Baryshkov Reviewed-by: Laurent Pinchart Link: https://patch.msgid.link/20260511-drm-bridge-alloc-getput-panel_or_bridge-v6-2-f61c9e498b3f@bootlin.com Signed-off-by: Luca Ceresoli --- include/drm/drm_bridge.h | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'include') diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h index fdac9a526f38..4ba3a5deef9a 100644 --- a/include/drm/drm_bridge.h +++ b/include/drm/drm_bridge.h @@ -1327,6 +1327,8 @@ int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge, #ifdef CONFIG_OF struct drm_bridge *of_drm_find_and_get_bridge(struct device_node *np); struct drm_bridge *of_drm_find_bridge(struct device_node *np); +struct drm_bridge *of_drm_get_bridge_by_endpoint(const struct device_node *np, + int port, int endpoint); #else static inline struct drm_bridge *of_drm_find_and_get_bridge(struct device_node *np) { @@ -1336,6 +1338,11 @@ static inline struct drm_bridge *of_drm_find_bridge(struct device_node *np) { return NULL; } +static inline struct drm_bridge *of_drm_get_bridge_by_endpoint(const struct device_node *np, + int port, int endpoint) +{ + return ERR_PTR(-ENODEV); +} #endif static inline bool drm_bridge_is_last(struct drm_bridge *bridge) -- cgit v1.2.3