linux-kernel - [PATCH v3 09/22] drm/bridge: simple-bridge: get/put the next bridge

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Message-Id: <20251216-drm-bridge-alloc-getput-drm_of_find_bridge-v3-9-b5165fab8058@bootlin.com>
Date: Tue, 16 Dec 2025 18:58:42 +0100
From: Luca Ceresoli <luca.ceresoli@...tlin.com>
To: 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>, 
 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>, 
 Jonathan Corbet <corbet@....net>, Alexey Brodkin <abrodkin@...opsys.com>, 
 Phong LE <ple@...libre.com>, Liu Ying <victor.liu@....com>, 
 Shawn Guo <shawnguo@...nel.org>, Sascha Hauer <s.hauer@...gutronix.de>, 
 Pengutronix Kernel Team <kernel@...gutronix.de>, 
 Fabio Estevam <festevam@...il.com>, Kevin Hilman <khilman@...libre.com>, 
 Jerome Brunet <jbrunet@...libre.com>, 
 Martin Blumenstingl <martin.blumenstingl@...glemail.com>
Cc: Hui Pu <Hui.Pu@...ealthcare.com>, 
 Thomas Petazzoni <thomas.petazzoni@...tlin.com>, 
 dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org, 
 linux-doc@...r.kernel.org, imx@...ts.linux.dev, 
 linux-arm-kernel@...ts.infradead.org, linux-amlogic@...ts.infradead.org, 
 Luca Ceresoli <luca.ceresoli@...tlin.com>
Subject: [PATCH v3 09/22] drm/bridge: simple-bridge: get/put the next
 bridge

This driver obtains a bridge pointer from of_drm_find_bridge() in the probe
function and stores it until driver removal. of_drm_find_bridge() is
deprecated. Move to of_drm_find_and_get_bridge() for the bridge to be
refcounted and use bridge->next_bridge to put the reference on
deallocation.

Signed-off-by: Luca Ceresoli <luca.ceresoli@...tlin.com>
---
 drivers/gpu/drm/bridge/simple-bridge.c | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/bridge/simple-bridge.c b/drivers/gpu/drm/bridge/simple-bridge.c
index 2cd1847ba776..873b32cfb508 100644
--- a/drivers/gpu/drm/bridge/simple-bridge.c
+++ b/drivers/gpu/drm/bridge/simple-bridge.c
@@ -31,7 +31,6 @@ struct simple_bridge {
 
 	const struct simple_bridge_info *info;
 
-	struct drm_bridge	*next_bridge;
 	struct regulator	*vdd;
 	struct gpio_desc	*enable;
 };
@@ -54,8 +53,8 @@ static int simple_bridge_get_modes(struct drm_connector *connector)
 	const struct drm_edid *drm_edid;
 	int ret;
 
-	if (sbridge->next_bridge->ops & DRM_BRIDGE_OP_EDID) {
-		drm_edid = drm_bridge_edid_read(sbridge->next_bridge, connector);
+	if (sbridge->bridge.next_bridge->ops & DRM_BRIDGE_OP_EDID) {
+		drm_edid = drm_bridge_edid_read(sbridge->bridge.next_bridge, connector);
 		if (!drm_edid)
 			DRM_INFO("EDID read failed. Fallback to standard modes\n");
 	} else {
@@ -90,7 +89,7 @@ simple_bridge_connector_detect(struct drm_connector *connector, bool force)
 {
 	struct simple_bridge *sbridge = drm_connector_to_simple_bridge(connector);
 
-	return drm_bridge_detect(sbridge->next_bridge, connector);
+	return drm_bridge_detect(sbridge->bridge.next_bridge, connector);
 }
 
 static const struct drm_connector_funcs simple_bridge_con_funcs = {
@@ -109,7 +108,7 @@ static int simple_bridge_attach(struct drm_bridge *bridge,
 	struct simple_bridge *sbridge = drm_bridge_to_simple_bridge(bridge);
 	int ret;
 
-	ret = drm_bridge_attach(encoder, sbridge->next_bridge, bridge,
+	ret = drm_bridge_attach(encoder, sbridge->bridge.next_bridge, bridge,
 				DRM_BRIDGE_ATTACH_NO_CONNECTOR);
 	if (ret < 0)
 		return ret;
@@ -122,7 +121,7 @@ static int simple_bridge_attach(struct drm_bridge *bridge,
 	ret = drm_connector_init_with_ddc(bridge->dev, &sbridge->connector,
 					  &simple_bridge_con_funcs,
 					  sbridge->info->connector_type,
-					  sbridge->next_bridge->ddc);
+					  sbridge->bridge.next_bridge->ddc);
 	if (ret) {
 		DRM_ERROR("Failed to initialize connector\n");
 		return ret;
@@ -180,10 +179,10 @@ static int simple_bridge_probe(struct platform_device *pdev)
 	if (!remote)
 		return -EINVAL;
 
-	sbridge->next_bridge = of_drm_find_bridge(remote);
+	sbridge->bridge.next_bridge = of_drm_find_and_get_bridge(remote);
 	of_node_put(remote);
 
-	if (!sbridge->next_bridge) {
+	if (!sbridge->bridge.next_bridge) {
 		dev_dbg(&pdev->dev, "Next bridge not found, deferring probe\n");
 		return -EPROBE_DEFER;
 	}

-- 
2.52.0