linux-kernel - [PATCH v2 33/34] drm/bridge: add devm_drm_put

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Message-Id: <20250424-drm-bridge-convert-to-alloc-api-v2-33-8f91a404d86b@bootlin.com>
Date: Thu, 24 Apr 2025 20:59:40 +0200
From: Luca Ceresoli <luca.ceresoli@...tlin.com>
To: Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, 
 Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>, 
 David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>, 
 Andrzej Hajda <andrzej.hajda@...el.com>, 
 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>, 
 Jagan Teki <jagan@...rulasolutions.com>, Shawn Guo <shawnguo@...nel.org>, 
 Sascha Hauer <s.hauer@...gutronix.de>, 
 Pengutronix Kernel Team <kernel@...gutronix.de>, 
 Fabio Estevam <festevam@...il.com>, 
 Douglas Anderson <dianders@...omium.org>, 
 Chun-Kuang Hu <chunkuang.hu@...nel.org>, 
 Krzysztof Kozlowski <krzk@...nel.org>
Cc: Anusha Srivatsa <asrivats@...hat.com>, 
 Paul Kocialkowski <paulk@...-base.io>, Dmitry Baryshkov <lumag@...nel.org>, 
 Hui Pu <Hui.Pu@...ealthcare.com>, 
 Thomas Petazzoni <thomas.petazzoni@...tlin.com>, 
 dri-devel@...ts.freedesktop.org, asahi@...ts.linux.dev, 
 linux-kernel@...r.kernel.org, chrome-platform@...ts.linux.dev, 
 imx@...ts.linux.dev, linux-arm-kernel@...ts.infradead.org, 
 linux-mediatek@...ts.infradead.org, linux-amlogic@...ts.infradead.org, 
 linux-renesas-soc@...r.kernel.org, platform-driver-x86@...r.kernel.org, 
 linux-samsung-soc@...r.kernel.org, linux-arm-msm@...r.kernel.org, 
 freedreno@...ts.freedesktop.org, linux-stm32@...md-mailman.stormreply.com, 
 Luca Ceresoli <luca.ceresoli@...tlin.com>
Subject: [PATCH v2 33/34] drm/bridge: add devm_drm_put_bridge()

Bridges obtained via devm_drm_bridge_alloc(dev, ...) will be put when the
requesting device (@dev) is removed.

However drivers which obtained them may need to put the obtained reference
explicitly. One such case is if they bind the devm removal action to a
different device than the one implemented by the driver itself and which
might be removed at a different time, such as bridge/panel.c.

Add devm_drm_put_bridge() to manually release a devm-obtained bridge in
such cases.

Signed-off-by: Luca Ceresoli <luca.ceresoli@...tlin.com>
---
 drivers/gpu/drm/drm_bridge.c | 14 ++++++++++++++
 include/drm/drm_bridge.h     |  4 ++++
 2 files changed, 18 insertions(+)

diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c
index b4c89ec01998b849018ce031c7cd84614e65e710..456363d86080b2a55035c3108c16afa4f9e57e06 100644
--- a/drivers/gpu/drm/drm_bridge.c
+++ b/drivers/gpu/drm/drm_bridge.c
@@ -1392,6 +1392,20 @@ struct drm_bridge *of_drm_find_bridge(struct device_node *np)
 EXPORT_SYMBOL(of_drm_find_bridge);
 #endif
 
+/**
+ * devm_drm_put_bridge - Release a bridge reference obtained via devm
+ * @dev: device that got the bridge via devm
+ * @bridge: pointer to a struct drm_bridge obtained via devm
+ *
+ * Same as drm_bridge_put() for bridge pointers obtained via devm functions
+ * such as devm_drm_bridge_alloc().
+ */
+void devm_drm_put_bridge(struct device *dev, struct drm_bridge *bridge)
+{
+	devm_release_action(dev, drm_bridge_put_void, bridge);
+}
+EXPORT_SYMBOL(devm_drm_put_bridge);
+
 static void drm_bridge_debugfs_show_bridge(struct drm_printer *p,
 					   struct drm_bridge *bridge,
 					   unsigned int idx)
diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
index 4e418a29a9ff9d014d6ac0910a5d9bcf7118195e..6f00a3998ed6d026332b0f1e3bb5bee3cb5158e0 100644
--- a/include/drm/drm_bridge.h
+++ b/include/drm/drm_bridge.h
@@ -1265,6 +1265,8 @@ static inline struct drm_bridge *devm_drm_of_get_bridge(struct device *dev,
 	return ERR_PTR(-ENODEV);
 }
 
+static inline void devm_drm_put_bridge(struct device *dev, struct drm_bridge *bridge) {}
+
 static inline struct drm_bridge *drmm_of_get_bridge(struct drm_device *drm,
 						     struct device_node *node,
 						     u32 port,
@@ -1274,6 +1276,8 @@ static inline struct drm_bridge *drmm_of_get_bridge(struct drm_device *drm,
 }
 #endif
 
+void devm_drm_put_bridge(struct device *dev, struct drm_bridge *bridge);
+
 void drm_bridge_debugfs_params(struct dentry *root);
 void drm_bridge_debugfs_encoder_params(struct dentry *root, struct drm_encoder *encoder);
 

-- 
2.49.0