linux-kernel - [PATCH 26/26] drm/bridge: imx8qxp-pixel-link: convert to drm_of_find

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Message-Id: <20251119-drm-bridge-alloc-getput-drm_of_find_bridge-v1-26-0db98a7fe474@bootlin.com>
Date: Wed, 19 Nov 2025 14:05:57 +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>, 
 Adrien Grassein <adrien.grassein@...il.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>, Kevin Hilman <khilman@...libre.com>, 
 Jerome Brunet <jbrunet@...libre.com>, 
 Martin Blumenstingl <martin.blumenstingl@...glemail.com>, 
 Chun-Kuang Hu <chunkuang.hu@...nel.org>, 
 Philipp Zabel <p.zabel@...gutronix.de>, 
 Matthias Brugger <matthias.bgg@...il.com>, 
 AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>, 
 Anitha Chrisanthus <anitha.chrisanthus@...el.com>, 
 Edmund Dea <edmund.j.dea@...el.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>
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-renesas-soc@...r.kernel.org, 
 linux-amlogic@...ts.infradead.org, linux-mediatek@...ts.infradead.org, 
 linux-samsung-soc@...r.kernel.org, 
 Luca Ceresoli <luca.ceresoli@...tlin.com>
Subject: [PATCH 26/26] drm/bridge: imx8qxp-pixel-link: convert to
 drm_of_find_bridge()

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

This needs to be handled in various steps:

 * the bridge returned drm_of_find_bridge() is stored in next_bridge whose
   scope is the for loop, so a cleanup action is enough
 * the value of next_bridge is copied into selected_bridge, potentially
   more than once, so a cleanup action at function scope is useful here too
 * however on successful return selected_bridge must be returned and
   ultimately stored, so it should not be put in that case: use
   return_ptr() to defuse the cleanup action on successful return
 * finally, put the bridge reference on device remove

Signed-off-by: Luca Ceresoli <luca.ceresoli@...tlin.com>

---

Cc: Liu Ying <victor.liu@....com>
---
 drivers/gpu/drm/bridge/imx/imx8qxp-pixel-link.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/bridge/imx/imx8qxp-pixel-link.c b/drivers/gpu/drm/bridge/imx/imx8qxp-pixel-link.c
index 2ecc3c1051e5..9818239cf6e7 100644
--- a/drivers/gpu/drm/bridge/imx/imx8qxp-pixel-link.c
+++ b/drivers/gpu/drm/bridge/imx/imx8qxp-pixel-link.c
@@ -256,12 +256,13 @@ static int imx8qxp_pixel_link_disable_all_controls(struct imx8qxp_pixel_link *pl
 	return imx8qxp_pixel_link_disable_sync(pl);
 }
 
+/* The returned bridge has its refcount incremented */
 static struct drm_bridge *
 imx8qxp_pixel_link_find_next_bridge(struct imx8qxp_pixel_link *pl)
 {
 	struct device_node *np = pl->dev->of_node;
 	struct device_node *port;
-	struct drm_bridge *selected_bridge = NULL;
+	struct drm_bridge *selected_bridge __free(drm_bridge_put) = NULL;
 	u32 port_id;
 	bool found_port = false;
 	int reg;
@@ -298,7 +299,7 @@ imx8qxp_pixel_link_find_next_bridge(struct imx8qxp_pixel_link *pl)
 			continue;
 		}
 
-		struct drm_bridge *next_bridge = of_drm_find_bridge(remote);
+		struct drm_bridge *next_bridge __free(drm_bridge_put) = drm_of_find_bridge(remote);
 		if (!next_bridge)
 			return ERR_PTR(-EPROBE_DEFER);
 
@@ -306,13 +307,15 @@ imx8qxp_pixel_link_find_next_bridge(struct imx8qxp_pixel_link *pl)
 		 * Select the next bridge with companion PXL2DPI if
 		 * present, otherwise default to the first bridge
 		 */
-		if (!selected_bridge || of_property_present(remote, "fsl,companion-pxl2dpi"))
-			selected_bridge = next_bridge;
+		if (!selected_bridge || of_property_present(remote, "fsl,companion-pxl2dpi")) {
+			drm_bridge_put(selected_bridge);
+			selected_bridge = drm_bridge_get(next_bridge);
+		}
 	}
 
 	pl->mst_addr = port_id - 1;
 
-	return selected_bridge;
+	return_ptr(selected_bridge);
 }
 
 static int imx8qxp_pixel_link_bridge_probe(struct platform_device *pdev)
@@ -392,6 +395,7 @@ static void imx8qxp_pixel_link_bridge_remove(struct platform_device *pdev)
 	struct imx8qxp_pixel_link *pl = platform_get_drvdata(pdev);
 
 	drm_bridge_remove(&pl->bridge);
+	drm_bridge_put(pl->next_bridge);
 }
 
 static const struct of_device_id imx8qxp_pixel_link_dt_ids[] = {

-- 
2.51.1