linux-kernel - [PATCH v2 2/6] drm/meson/dw-hdmi: convert to of_drm_find_and_get

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Message-Id: <20260109-drm-bridge-alloc-getput-drm_of_find_bridge-3-v2-2-8d7a3dbacdf4@bootlin.com>
Date: Fri, 09 Jan 2026 11:02:51 +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>, 
 Kevin Hilman <khilman@...libre.com>, Jerome Brunet <jbrunet@...libre.com>, 
 Martin Blumenstingl <martin.blumenstingl@...glemail.com>, 
 Philipp Zabel <p.zabel@...gutronix.de>, Shawn Guo <shawnguo@...nel.org>, 
 Sascha Hauer <s.hauer@...gutronix.de>, 
 Pengutronix Kernel Team <kernel@...gutronix.de>, 
 Fabio Estevam <festevam@...il.com>, Chun-Kuang Hu <chunkuang.hu@...nel.org>, 
 Matthias Brugger <matthias.bgg@...il.com>, 
 AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>, 
 Inki Dae <inki.dae@...sung.com>, Seung-Woo Kim <sw0312.kim@...sung.com>, 
 Kyungmin Park <kyungmin.park@...sung.com>, 
 Krzysztof Kozlowski <krzk@...nel.org>, 
 Alim Akhtar <alim.akhtar@...sung.com>, 
 Laurent Pinchart <laurent.pinchart+renesas@...asonboard.com>, 
 Tomi Valkeinen <tomi.valkeinen+renesas@...asonboard.com>, 
 Kieran Bingham <kieran.bingham+renesas@...asonboard.com>, 
 Geert Uytterhoeven <geert+renesas@...der.be>, 
 Magnus Damm <magnus.damm@...il.com>
Cc: Marek Szyprowski <m.szyprowski@...sung.com>, 
 Hui Pu <Hui.Pu@...ealthcare.com>, 
 Thomas Petazzoni <thomas.petazzoni@...tlin.com>, 
 dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org, 
 linux-amlogic@...ts.infradead.org, linux-arm-kernel@...ts.infradead.org, 
 imx@...ts.linux.dev, linux-mediatek@...ts.infradead.org, 
 linux-samsung-soc@...r.kernel.org, linux-renesas-soc@...r.kernel.org, 
 Luca Ceresoli <luca.ceresoli@...tlin.com>
Subject: [PATCH v2 2/6] drm/meson/dw-hdmi: convert to
 of_drm_find_and_get_bridge()

of_drm_find_bridge() is deprecated. Move to its replacement
of_drm_find_and_get_bridge() which gets a bridge reference, and ensure it
is put when done.

dw_hdmi->bridge is used only in dw_hdmi_top_thread_irq(), so in order to
avoid potential use-after-free ensure the irq is freed before putting the
dw_hdmi->bridge reference.

Acked-by: Maxime Ripard <mripard@...nel.org>
Signed-off-by: Luca Ceresoli <luca.ceresoli@...tlin.com>
---
 drivers/gpu/drm/meson/meson_dw_hdmi.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/meson/meson_dw_hdmi.c b/drivers/gpu/drm/meson/meson_dw_hdmi.c
index 0d7c68b29dff..fef1702acb14 100644
--- a/drivers/gpu/drm/meson/meson_dw_hdmi.c
+++ b/drivers/gpu/drm/meson/meson_dw_hdmi.c
@@ -778,7 +778,7 @@ static int meson_dw_hdmi_bind(struct device *dev, struct device *master,
 	if (IS_ERR(meson_dw_hdmi->hdmi))
 		return PTR_ERR(meson_dw_hdmi->hdmi);
 
-	meson_dw_hdmi->bridge = of_drm_find_bridge(pdev->dev.of_node);
+	meson_dw_hdmi->bridge = of_drm_find_and_get_bridge(pdev->dev.of_node);
 
 	DRM_DEBUG_DRIVER("HDMI controller initialized\n");
 
@@ -789,8 +789,12 @@ static void meson_dw_hdmi_unbind(struct device *dev, struct device *master,
 				   void *data)
 {
 	struct meson_dw_hdmi *meson_dw_hdmi = dev_get_drvdata(dev);
+	struct platform_device *pdev = to_platform_device(dev);
+	int irq = platform_get_irq(pdev, 0);
 
+	devm_free_irq(dev, irq, meson_dw_hdmi);
 	dw_hdmi_unbind(meson_dw_hdmi->hdmi);
+	drm_bridge_put(meson_dw_hdmi->bridge);
 }
 
 static const struct component_ops meson_dw_hdmi_ops = {

-- 
2.52.0