linux-kernel - [PATCH v6 10/26] drm/bridge: add devm_drm_of_get_bridge_by

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <20250206-hotplug-drm-bridge-v6-10-9d6f2c9c3058@bootlin.com>
Date: Thu, 06 Feb 2025 19:14:25 +0100
From: Luca Ceresoli <luca.ceresoli@...tlin.com>
To: Simona Vetter <simona@...ll.ch>, Inki Dae <inki.dae@...sung.com>, 
 Jagan Teki <jagan@...rulasolutions.com>, 
 Marek Szyprowski <m.szyprowski@...sung.com>, 
 Catalin Marinas <catalin.marinas@....com>, Will Deacon <will@...nel.org>, 
 Shawn Guo <shawnguo@...nel.org>, Sascha Hauer <s.hauer@...gutronix.de>, 
 Pengutronix Kernel Team <kernel@...gutronix.de>, 
 Fabio Estevam <festevam@...il.com>, Daniel Thompson <danielt@...nel.org>, 
 Andrzej Hajda <andrzej.hajda@...el.com>, Jonathan Corbet <corbet@....net>, 
 Sam Ravnborg <sam@...nborg.org>, Boris Brezillon <bbrezillon@...nel.org>, 
 Nicolas Ferre <nicolas.ferre@...rochip.com>, 
 Alexandre Belloni <alexandre.belloni@...tlin.com>, 
 Claudiu Beznea <claudiu.beznea@...on.dev>, 
 Jessica Zhang <quic_jesszhan@...cinc.com>
Cc: Paul Kocialkowski <contact@...lk.fr>, 
 Maxime Ripard <mripard@...nel.org>, 
 Dmitry Baryshkov <dmitry.baryshkov@...aro.org>, 
 Neil Armstrong <neil.armstrong@...aro.org>, Robert Foss <rfoss@...nel.org>, 
 Laurent Pinchart <Laurent.pinchart@...asonboard.com>, 
 Jonas Karlman <jonas@...boo.se>, Jernej Skrabec <jernej.skrabec@...il.com>, 
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, 
 Thomas Zimmermann <tzimmermann@...e.de>, David Airlie <airlied@...il.com>, 
 Hervé Codina <herve.codina@...tlin.com>, 
 Thomas Petazzoni <thomas.petazzoni@...tlin.com>, 
 linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org, 
 linux-doc@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, 
 Paul Kocialkowski <paul.kocialkowski@...tlin.com>, 
 Luca Ceresoli <luca.ceresoli@...tlin.com>
Subject: [PATCH v6 10/26] drm/bridge: add devm_drm_of_get_bridge_by_node()

devm_drm_of_get_bridge(), which is based on graph links, is the recommended
function to get a pointer to the following bridge.

This is valid even for panels, for which the recommended device tree
description is via graph links and not (or not only) panel subnodes of a
panel controller (e.g. "dsi@...4" controller node with a "panel@0"
subnode).

However there are drivers supporting the panel subnode description in
addition to the graph links. For those drivers add a _by_node variant that
takes the node of the target node.

Suggested-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
Signed-off-by: Luca Ceresoli <luca.ceresoli@...tlin.com>

---

This patch was added in v6.
---
 drivers/gpu/drm/drm_bridge.c | 30 ++++++++++++++++++++++++++++++
 include/drm/drm_bridge.h     |  8 ++++++++
 2 files changed, 38 insertions(+)

diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
index 2aa17fbe538b86066c4e68f0d0e8046e9ca9b965..b0834b8644284e5f7751cec81724af849b4180e7 100644
--- a/drivers/gpu/drm/drm_bridge.c
+++ b/drivers/gpu/drm/drm_bridge.c
@@ -1407,6 +1407,36 @@ struct drm_bridge *devm_drm_of_get_bridge(struct device *dev,
 }
 EXPORT_SYMBOL(devm_drm_of_get_bridge);
 
+/**
+ * devm_drm_of_get_bridge_by_node - Return bridge for a given OF node
+ * @dev: device to tie the bridge lifetime to
+ * @bridge_node: device node of the remote bridge
+ *
+ * Given a bridge DT node, returns the associated bridge if any. This
+ * should be used in addition to devm_drm_of_get_bridge() when the regular
+ * graph link search is not enough, e.g. for drivers that need to support
+ * panels described only as subnodes.
+ *
+ * RETURNS:
+ * A pointer to the bridge if successful, or an error pointer otherwise.
+ */
+struct drm_bridge *devm_drm_of_get_bridge_by_node(struct device *dev,
+						  struct device_node *bridge_node)
+{
+	struct drm_bridge *bridge;
+	int ret;
+
+	if (!bridge_node)
+		return ERR_PTR(-EINVAL);
+
+	bridge = of_drm_find_bridge(bridge_node);
+	if (!bridge)
+		return ERR_PTR(-ENODEV);
+
+	return bridge;
+}
+EXPORT_SYMBOL(devm_drm_of_get_bridge_by_node);
+
 /**
  * drmm_of_get_bridge - Return next bridge in the chain
  * @drm: device to tie the bridge lifetime to
diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
index 496dbbd2ad7edff7f091adfbe62de1e33ef0cf07..1561347c4991dac6022319774510f9560c9283c3 100644
--- a/include/drm/drm_bridge.h
+++ b/include/drm/drm_bridge.h
@@ -1088,6 +1088,8 @@ static inline int drm_panel_bridge_set_orientation(struct drm_connector *connect
 #if defined(CONFIG_OF) && defined(CONFIG_DRM_PANEL_BRIDGE)
 struct drm_bridge *devm_drm_of_get_bridge(struct device *dev, struct device_node *node,
 					  u32 port, u32 endpoint);
+struct drm_bridge *devm_drm_of_get_bridge_by_node(struct device *dev,
+						  struct device_node *bridge_node);
 struct drm_bridge *drmm_of_get_bridge(struct drm_device *drm, struct device_node *node,
 					  u32 port, u32 endpoint);
 #else
@@ -1099,6 +1101,12 @@ static inline struct drm_bridge *devm_drm_of_get_bridge(struct device *dev,
 	return ERR_PTR(-ENODEV);
 }
 
+static inline struct drm_bridge *devm_drm_of_get_bridge_by_node(struct device *dev,
+								struct device_node *bridge_node)
+{
+	return ERR_PTR(-ENODEV);
+}
+
 static inline struct drm_bridge *drmm_of_get_bridge(struct drm_device *drm,
 						     struct device_node *node,
 						     u32 port,

-- 
2.34.1