[PATCH RFC v2 19/19] drm/bridge: analogix_dp: don't create a panel_bridge

[Luca Ceresoli <luca.ceresoli@bootlin.com>]

Now a panel_bridge is automatically created for every drm_panel, so this
call to devm_drm_panel_bridge_add() would lead to creating a second bridge
for the same panel.

Update and simplify the code by just getting a reference to the
already-existing bridge.

as of_drm_get_bridge_by_endpoint() returns a refcounted bridge, take care
of putting the bridge reference. This is not easily done in the remove path
due to the different probe paths of the user drivers, so add a devm action
to ensure the reference is put only when it was taken.

Assisted-by: opencode:deepseek-v4-flash-0731
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
---
 drivers/gpu/drm/bridge/analogix/Kconfig            |  2 --
 drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 40 +++++++++++++---------
 drivers/gpu/drm/exynos/exynos_dp.c                 | 36 ++-----------------
 drivers/gpu/drm/rockchip/analogix_dp-rockchip.c    |  9 -----
 include/drm/bridge/analogix_dp.h                   |  1 -
 5 files changed, 25 insertions(+), 63 deletions(-)

diff --git a/drivers/gpu/drm/bridge/analogix/Kconfig b/drivers/gpu/drm/bridge/analogix/Kconfig
index d07431788fcb..1e7726c76361 100644
--- a/drivers/gpu/drm/bridge/analogix/Kconfig
+++ b/drivers/gpu/drm/bridge/analogix/Kconfig
@@ -34,8 +34,6 @@ config DRM_ANALOGIX_DP
 	depends on DRM
 	depends on OF
 	select DRM_DISPLAY_DP_AUX_BUS
-	select DRM_PANEL
-	select DRM_PANEL_BRIDGE
 
 config DRM_ANALOGIX_ANX7625
 	tristate "Analogix Anx7625 MIPI to DP interface support"
diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
index 566f1e5eb8cd..233bdaea8012 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
@@ -29,7 +29,6 @@
 #include <drm/drm_device.h>
 #include <drm/drm_edid.h>
 #include <drm/drm_of.h>
-#include <drm/drm_panel.h>
 #include <drm/drm_print.h>
 #include <drm/drm_probe_helper.h>
 
@@ -1491,15 +1490,6 @@ int analogix_dp_bind(struct analogix_dp_device *dp, struct drm_device *drm_dev)
 	if (ret)
 		goto err_unregister_aux;
 
-	if (dp->plat_data->panel) {
-		dp->plat_data->next_bridge = devm_drm_panel_bridge_add(dp->dev,
-								       dp->plat_data->panel);
-		if (IS_ERR(dp->plat_data->next_bridge)) {
-			ret = PTR_ERR(dp->plat_data->next_bridge);
-			goto err_unregister_aux;
-		}
-	}
-
 	ret = drm_bridge_attach(dp->encoder, bridge, NULL, DRM_BRIDGE_ATTACH_NO_CONNECTOR);
 	if (ret) {
 		DRM_ERROR("failed to create bridge (%d)\n", ret);
@@ -1571,6 +1561,11 @@ struct drm_dp_aux *analogix_dp_get_aux(struct analogix_dp_device *dp)
 }
 EXPORT_SYMBOL_GPL(analogix_dp_get_aux);
 
+static void analogix_dp_put_bridge(void *data)
+{
+	drm_bridge_put(data);
+}
+
 static int analogix_dp_aux_done_probing(struct drm_dp_aux *aux)
 {
 	struct analogix_dp_device *dp = to_dp(aux);
@@ -1579,14 +1574,25 @@ static int analogix_dp_aux_done_probing(struct drm_dp_aux *aux)
 	int ret;
 
 	/*
-	 * If drm_of_find_panel_or_bridge() returns -ENODEV, there may be no valid panel
-	 * or bridge nodes. The driver should go on for the driver-free bridge or the DP
-	 * mode applications.
+	 * If of_drm_get_bridge_by_endpoint() returns -ENODEV, there may be no
+	 * valid panel or bridge nodes. The driver should go on for the
+	 * driver-free bridge or the DP mode applications.
 	 */
-	ret = drm_of_find_panel_or_bridge(dp->dev->of_node, port, 0,
-					  &plat_data->panel, &plat_data->next_bridge);
-	if (ret && ret != -ENODEV)
-		return ret;
+	plat_data->next_bridge = of_drm_get_bridge_by_endpoint(dp->dev->of_node,
+							       port, 0);
+	if (IS_ERR(plat_data->next_bridge)) {
+		if (PTR_ERR(plat_data->next_bridge) == -ENODEV)
+			plat_data->next_bridge = NULL;
+		else
+			return PTR_ERR(plat_data->next_bridge);
+	}
+
+	if (plat_data->next_bridge) {
+		ret = devm_add_action_or_reset(dp->dev, analogix_dp_put_bridge,
+					       plat_data->next_bridge);
+		if (ret)
+			return ret;
+	}
 
 	return component_add(dp->dev, plat_data->ops);
 }
diff --git a/drivers/gpu/drm/exynos/exynos_dp.c b/drivers/gpu/drm/exynos/exynos_dp.c
index e1c9e2946b8a..82c238829921 100644
--- a/drivers/gpu/drm/exynos/exynos_dp.c
+++ b/drivers/gpu/drm/exynos/exynos_dp.c
@@ -26,7 +26,6 @@
 #include <drm/drm_crtc.h>
 #include <drm/drm_encoder.h>
 #include <drm/drm_of.h>
-#include <drm/drm_panel.h>
 #include <drm/drm_print.h>
 #include <drm/drm_probe_helper.h>
 #include <drm/exynos_drm.h>
@@ -147,7 +146,6 @@ static const struct component_ops exynos_dp_ops = {
 static int exynos_dp_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
-	struct device_node *np;
 	struct exynos_dp_device *dp;
 
 	dp = devm_kzalloc(&pdev->dev, sizeof(struct exynos_dp_device),
@@ -163,18 +161,6 @@ static int exynos_dp_probe(struct platform_device *pdev)
 	 */
 	platform_set_drvdata(pdev, dp);
 
-	/* This is for the backward compatibility. */
-	np = of_parse_phandle(dev->of_node, "panel", 0);
-	if (np) {
-		dp->plat_data.panel = of_drm_find_panel(np);
-
-		of_node_put(np);
-		if (IS_ERR(dp->plat_data.panel))
-			return PTR_ERR(dp->plat_data.panel);
-
-		goto out;
-	}
-
 	if (of_get_display_timings(dev->of_node)) {
 		dp->plat_data.next_bridge = devm_drm_of_display_mode_bridge(dp->dev,
 									dp->dev->of_node,
@@ -189,19 +175,11 @@ static int exynos_dp_probe(struct platform_device *pdev)
 	dp->plat_data.power_off = exynos_dp_poweroff;
 	dp->plat_data.ops = &exynos_dp_ops;
 
-out:
 	dp->adp = analogix_dp_probe(dev, &dp->plat_data);
-	if (IS_ERR(dp->adp)) {
-		/*
-		 * The driver core does not invoke remove() for failed probes,
-		 * so release the probe-time panel reference here.
-		 */
-		if (dp->plat_data.panel)
-			drm_panel_put(dp->plat_data.panel);
+	if (IS_ERR(dp->adp))
 		return PTR_ERR(dp->adp);
-	}
 
-	if (dp->plat_data.panel || dp->plat_data.next_bridge)
+	if (dp->plat_data.next_bridge)
 		return component_add(&pdev->dev, &exynos_dp_ops);
 	else
 		return analogix_dp_finish_probe(dp->adp);
@@ -209,16 +187,6 @@ static int exynos_dp_probe(struct platform_device *pdev)
 
 static void exynos_dp_remove(struct platform_device *pdev)
 {
-	struct exynos_dp_device *dp = platform_get_drvdata(pdev);
-
-	/*
-	 * Release the probe-time reference from of_drm_find_panel(). If bind
-	 * ran, the panel_bridge holds a second reference that devm cleanup
-	 * will release when the bridge is destroyed after remove() returns.
-	 */
-	if (dp->plat_data.panel)
-		drm_panel_put(dp->plat_data.panel);
-
 	component_del(&pdev->dev, &exynos_dp_ops);
 }
 
diff --git a/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c b/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
index 587e60232ec7..071d31aa5288 100644
--- a/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
+++ b/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
@@ -28,7 +28,6 @@
 #include <drm/drm_bridge_connector.h>
 #include <drm/bridge/analogix_dp.h>
 #include <drm/drm_of.h>
-#include <drm/drm_panel.h>
 #include <drm/drm_print.h>
 #include <drm/drm_probe_helper.h>
 
@@ -488,14 +487,6 @@ static void rockchip_dp_remove(struct platform_device *pdev)
 {
 	struct rockchip_dp_device *dp = platform_get_drvdata(pdev);
 
-	/*
-	 * Release the probe-time reference from of_drm_find_panel(). If bind
-	 * ran, the panel_bridge holds a second reference that devm cleanup
-	 * will release when the bridge is destroyed after remove() returns.
-	 */
-	if (dp->plat_data.panel)
-		drm_panel_put(dp->plat_data.panel);
-
 	component_del(&pdev->dev, &rockchip_dp_component_ops);
 }
 
diff --git a/include/drm/bridge/analogix_dp.h b/include/drm/bridge/analogix_dp.h
index 0e0b87abee59..6033137b651e 100644
--- a/include/drm/bridge/analogix_dp.h
+++ b/include/drm/bridge/analogix_dp.h
@@ -35,7 +35,6 @@ static inline bool analogix_dp_is_rockchip(enum analogix_dp_devtype type)
 
 struct analogix_dp_plat_data {
 	enum analogix_dp_devtype dev_type;
-	struct drm_panel *panel;
 	struct drm_bridge *next_bridge;
 	struct drm_encoder *encoder;
 	struct drm_connector *connector;

-- 
2.55.0