From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtpout-02.galae.net (smtpout-02.galae.net [185.246.84.56]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A32983F7875 for ; Thu, 7 May 2026 13:45:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.246.84.56 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778161558; cv=none; b=AjklAB97kBXE2/XveNp83M+RLBnoEwmOGTzjKr8j5FBjjcH/uAQLOYATCmyWm7KB3EyyRJ657F2Ql3W1QfEqxkyZir8p8Ku2NJ6SzRmSk5o8vHgnvRHAUMUCo046k3NXJJIpW3WeO0vgMejOCXHhmlfNswmWihdVilQ4l8KEGYc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778161558; c=relaxed/simple; bh=2QzGLsEZAuI/Mqhoj0Xz9pzhkAKeneTzvWMm7ieiRx8=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=C4eW/yIowHzjURmgO9XqmS64jBj1EKeiNWZvNzuHmohPHQYpl+pP5lAl8AHPbtXGUexd8UNfh+1JIPpJ2aMgrPE4YEI39CK+v9zNLvzzh/Uoj8Z0pVN+LGKMUL6QTgtB+g+VH87QHWEZRl5/4EkdvL95XAG139eEsONaMK2M5Ko= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com; spf=pass smtp.mailfrom=bootlin.com; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b=bJGZ0SRj; arc=none smtp.client-ip=185.246.84.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bootlin.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b="bJGZ0SRj" Received: from smtpout-01.galae.net (smtpout-01.galae.net [212.83.139.233]) by smtpout-02.galae.net (Postfix) with ESMTPS id 3332B1A3556; Thu, 7 May 2026 13:45:54 +0000 (UTC) Received: from mail.galae.net (mail.galae.net [212.83.136.155]) by smtpout-01.galae.net (Postfix) with ESMTPS id 062EA60495; Thu, 7 May 2026 13:45:54 +0000 (UTC) Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id C534B102F291C; Thu, 7 May 2026 15:45:48 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=dkim; t=1778161552; h=from:subject:date:message-id:to:cc:mime-version:content-type: content-transfer-encoding:in-reply-to:references; bh=Z6Yw5IeNbztqy9jznr3VYHLfUqnfTnc5ZkHTRNnsNKo=; b=bJGZ0SRjsgSZZYZ49AMjuqMDaPi5hwh27UYFFC1GVfzubKoQ/ff7YfBBhUeyMVlCpyJGNo aX377J5GIRUbeZYfdhnsEyyoVdZCIjFc4hmqtvRe5gAM6RhXugOt5qEYMxrwm+qyVYKtw5 1TLpBjeyDe8PSSDQQnH4/j33S/Udozk02pTl1BvZ7hHdZuJk5pbxF+n+dACtIEm5Yxge1E Iq97kulWDE3zN7Q1d5Pmc48DnPaxJ22XNYP19WPWcpWO+wh4lRBjuf3/3x9PDn/Ofyc/OP g3vEacia2jyaIXTBLNE10IPaHfojeg75oOsvuY7LUfJzepBi+ObcK6w+a8bZmw== From: Luca Ceresoli Date: Thu, 07 May 2026 15:45:20 +0200 Subject: [PATCH v5 02/11] drm/bridge: add of_drm_get_bridge_by_endpoint() Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260507-drm-bridge-alloc-getput-panel_or_bridge-v5-2-472b913b5cb7@bootlin.com> References: <20260507-drm-bridge-alloc-getput-panel_or_bridge-v5-0-472b913b5cb7@bootlin.com> In-Reply-To: <20260507-drm-bridge-alloc-getput-panel_or_bridge-v5-0-472b913b5cb7@bootlin.com> To: Andrzej Hajda , Neil Armstrong , Robert Foss , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Rob Clark , Dmitry Baryshkov , Abhinav Kumar , Jessica Zhang , Sean Paul , Marijn Suijten , Sumit Semwal , John Stultz , Tomi Valkeinen , Michal Simek Cc: Hui Pu , Ian Ray , Thomas Petazzoni , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, freedreno@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org, Luca Ceresoli , Dmitry Baryshkov , Laurent Pinchart X-Mailer: b4 0.15.2 X-Last-TLS-Session-Version: TLSv1.3 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 Signed-off-by: Luca Ceresoli --- Changes in v4: - update function declaration in non-OF case - fix grammar in comment Changes in v2: - return the bridge in the return value, not a double pointer --- drivers/gpu/drm/drm_bridge.c | 41 +++++++++++++++++++++++++++++++++++++++++ include/drm/drm_bridge.h | 7 +++++++ 2 files changed, 48 insertions(+) diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c index 4aaea517b436..55384e257c50 100644 --- a/drivers/gpu/drm/drm_bridge.c +++ b/drivers/gpu/drm/drm_bridge.c @@ -1582,6 +1582,47 @@ struct drm_bridge *of_drm_find_bridge(struct device_node *np) return bridge; } EXPORT_SYMBOL(of_drm_find_bridge); + +/** + * of_drm_get_bridge_by_endpoint - return DRM bridge connected to a port/endpoint + * @np: device tree node containing output ports + * @port: port in the device tree node, or -1 for the first port found + * @endpoint: endpoint in the device tree node, or -1 for the first endpoint found + * + * Given a DT node's port and endpoint number, find the connected node and + * return the associated drm_bridge device. + * + * The refcount of the returned bridge is incremented. Use drm_bridge_put() + * when done with it. + * + * Returns a pointer to the connected drm_bridge, or a negative error on failure + */ +struct drm_bridge *of_drm_get_bridge_by_endpoint(const struct device_node *np, + int port, int endpoint) +{ + struct drm_bridge *bridge; + + /* + * of_graph_get_remote_node() produces a noisy error message if port + * node isn't found and the absence of the port is a legit case here, + * so at first we silently check whether graph is present in the + * device-tree node. + */ + if (!of_graph_is_present(np)) + return ERR_PTR(-ENODEV); + + struct device_node *remote __free(device_node) = + of_graph_get_remote_node(np, port, endpoint); + if (!remote) + return ERR_PTR(-ENODEV); + + bridge = of_drm_find_and_get_bridge(remote); + if (!bridge) + return ERR_PTR(-EPROBE_DEFER); + + return bridge; +} +EXPORT_SYMBOL_GPL(of_drm_get_bridge_by_endpoint); #endif /** diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h index d6cd0f5af045..31e11a360c42 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 -ENODEV; +} #endif static inline bool drm_bridge_is_last(struct drm_bridge *bridge) -- 2.53.0