[PATCH v4 08/11] drm/bridge: adv7511: switch to of_drm_get_bridge_by_endpoint()

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

This driver calls drm_of_find_panel_or_bridge() with a NULL pointer in the
@panel parameter, thus using a reduced feature set of that function.
Replace this call with the simpler of_drm_get_bridge_by_endpoint().

Since of_drm_get_bridge_by_endpoint() increases the refcount of the
returned bridge, ensure it is put on removal. To achieve this, instead of
adding an explicit drm_bridge_put(), migrate to the bridge::next_bridge
pointer which is automatically put when the bridge is eventually freed.

Tested-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
---
Changes in v3:
- fix ERR_PTR deref when -ENODEV is returned
---
 drivers/gpu/drm/bridge/adv7511/adv7511.h     |  1 -
 drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 15 +++++++++------
 2 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511.h b/drivers/gpu/drm/bridge/adv7511/adv7511.h
index 8be7266fd4f4..12c95198d9a4 100644
--- a/drivers/gpu/drm/bridge/adv7511/adv7511.h
+++ b/drivers/gpu/drm/bridge/adv7511/adv7511.h
@@ -354,7 +354,6 @@ struct adv7511 {
 	enum drm_connector_status status;
 	bool powered;
 
-	struct drm_bridge *next_bridge;
 	struct drm_display_mode curr_mode;
 
 	unsigned int f_tmds;
diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
index f318080f1139..8304978535e4 100644
--- a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
+++ b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c
@@ -849,8 +849,8 @@ static int adv7511_bridge_attach(struct drm_bridge *bridge,
 	struct adv7511 *adv = bridge_to_adv7511(bridge);
 	int ret = 0;
 
-	if (adv->next_bridge) {
-		ret = drm_bridge_attach(encoder, adv->next_bridge, bridge,
+	if (adv->bridge.next_bridge) {
+		ret = drm_bridge_attach(encoder, adv->bridge.next_bridge, bridge,
 					flags | DRM_BRIDGE_ATTACH_NO_CONNECTOR);
 		if (ret)
 			return ret;
@@ -1249,10 +1249,13 @@ static int adv7511_probe(struct i2c_client *i2c)
 
 	memset(&link_config, 0, sizeof(link_config));
 
-	ret = drm_of_find_panel_or_bridge(dev->of_node, 1, -1, NULL,
-					  &adv7511->next_bridge);
-	if (ret && ret != -ENODEV)
-		return ret;
+	adv7511->bridge.next_bridge = of_drm_get_bridge_by_endpoint(dev->of_node, 1, -1);
+	if (IS_ERR(adv7511->bridge.next_bridge)) {
+		if (PTR_ERR(adv7511->bridge.next_bridge) == -ENODEV)
+			adv7511->bridge.next_bridge = NULL;
+		else
+			return PTR_ERR(adv7511->bridge.next_bridge);
+	}
 
 	if (adv7511->info->link_config)
 		ret = adv7511_parse_dt(dev->of_node, &link_config);

-- 
2.53.0