[PATCH v10 06/11] drm/rockchip: analogix_dp: Fix OF node reference leak via auto cleanup

[Damon Ding]

Sashiko reported a reference leak in rockchip_dp_drm_encoder_enable(),
the of_get_child_by_name() function does not call of_node_put() in a
symmetrical way [1].

Fix the device node reference leak by using __free(device_node) to
automatically manage of_node_put() for all device nodes.

Fixes: 729f8eefdcad ("drm/rockchip: analogix_dp: Add support for RK3588")
Link: https://sashiko.dev/#/patchset/20260527024336.191433-1-damon.ding@rock-chips.com?part=5 #1
Signed-off-by: Damon Ding <damon.ding at rock-chips.com>
---
 drivers/gpu/drm/rockchip/analogix_dp-rockchip.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c b/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
index d2af5eb29dbb..b1ed25cefe5e 100644
--- a/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
+++ b/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
@@ -8,6 +8,7 @@
  *         Jeff Chen <jeff.chen at rock-chips.com>
  */
 
+#include <linux/cleanup.h>
 #include <linux/component.h>
 #include <linux/mfd/syscon.h>
 #include <linux/of.h>
@@ -206,7 +207,6 @@ static void rockchip_dp_drm_encoder_enable(struct drm_encoder *encoder,
 	struct drm_crtc *crtc;
 	struct drm_crtc_state *old_crtc_state;
 	struct of_endpoint endpoint;
-	struct device_node *remote_port, *remote_port_parent;
 	char name[32];
 	u32 port_id;
 	int ret;
@@ -230,18 +230,22 @@ static void rockchip_dp_drm_encoder_enable(struct drm_encoder *encoder,
 	if (ret < 0)
 		return;
 
-	remote_port_parent = of_graph_get_remote_port_parent(endpoint.local_node);
+	struct device_node *remote_port_parent __free(device_node) =
+		of_graph_get_remote_port_parent(endpoint.local_node);
 	if (remote_port_parent) {
-		if (of_get_child_by_name(remote_port_parent, "ports")) {
-			remote_port = of_graph_get_remote_port(endpoint.local_node);
+		struct device_node *ports __free(device_node) =
+			of_get_child_by_name(remote_port_parent, "ports");
+
+		if (ports) {
+			struct device_node *remote_port __free(device_node) =
+				of_graph_get_remote_port(endpoint.local_node);
+
 			of_property_read_u32(remote_port, "reg", &port_id);
-			of_node_put(remote_port);
 			sprintf(name, "%s vp%d", remote_port_parent->full_name, port_id);
 		} else {
 			sprintf(name, "%s %s",
 				remote_port_parent->full_name, endpoint.id ? "vopl" : "vopb");
 		}
-		of_node_put(remote_port_parent);
 
 		DRM_DEV_DEBUG(dp->dev, "vop %s output to dp\n", (ret) ? "LIT" : "BIG");
 	}
-- 
2.34.1