While bridge/panel detection was initially relying on the usual port/ports-based of graph detection, it was recently changed to perform the lookup on any child node that is not port/ports instead when such a node is available, with no fallback on the usual way.

This results in breaking detection when a child node is present but does not contain any panel or bridge node, even when the usual port/ports-based of graph is there.

In order to support both situations properly, this commit reworks the logic to try both options and not just one of the two: it will only return -EPROBE_DEFER when both have failed.

Signed-off-by: Paul Kocialkowski paul.kocialkowski@bootlin.com Fixes: 80253168dbfd ("drm: of: Lookup if child node has panel or bridge") ---

Changes since v1: - Renamed remote to node; - Renamed helper to find_panel_or_bridge; - Cleared bridge pointer early; - Returned early to make the code more concise;

--- drivers/gpu/drm/drm_of.c | 98 ++++++++++++++++++++-------------------- 1 file changed, 49 insertions(+), 49 deletions(-)

diff --git a/drivers/gpu/drm/drm_of.c b/drivers/gpu/drm/drm_of.c index 9d90cd75c457..63137c833b7a 100644 --- a/drivers/gpu/drm/drm_of.c +++ b/drivers/gpu/drm/drm_of.c @@ -219,6 +219,28 @@ int drm_of_encoder_active_endpoint(struct device_node *node, } EXPORT_SYMBOL_GPL(drm_of_encoder_active_endpoint);

+static int find_panel_or_bridge(struct device_node *node, + struct drm_panel **panel, + struct drm_bridge **bridge) +{ + if (panel) { + *panel = of_drm_find_panel(node); + if (!IS_ERR(*panel)) + return 0; + else + *panel = NULL; + } + + /* No panel found yet, check for a bridge next. */ + if (bridge) { + *bridge = of_drm_find_bridge(node); + if (*bridge) + return 0; + } + + return -EPROBE_DEFER; +} + /** * drm_of_find_panel_or_bridge - return connected panel or bridge device * @np: device tree node containing encoder output ports @@ -241,66 +263,44 @@ int drm_of_find_panel_or_bridge(const struct device_node *np, struct drm_panel **panel, struct drm_bridge **bridge) { - int ret = -EPROBE_DEFER; - struct device_node *remote; + struct device_node *node; + int ret;

if (!panel && !bridge) return -EINVAL; + if (panel) *panel = NULL; - - /** - * Devices can also be child nodes when we also control that device - * through the upstream device (ie, MIPI-DCS for a MIPI-DSI device). - * - * Lookup for a child node of the given parent that isn't either port - * or ports. - */ - for_each_available_child_of_node(np, remote) { - if (of_node_name_eq(remote, "port") || - of_node_name_eq(remote, "ports")) - continue; - - goto of_find_panel_or_bridge; + if (bridge) + *bridge = NULL; + + /* Check for a graph on the device node first. */ + if (of_graph_is_present(np)) { + node = of_graph_get_remote_node(np, port, endpoint); + if (node) { + ret = find_panel_or_bridge(node, panel, bridge); + of_node_put(node); + + if (!ret) + return 0; + } }

- /* - * of_graph_get_remote_node() produces a noisy error message if port - * node isn't found and the absence of the port is a legit case here, - * so at first we silently check whether graph presents in the - * device-tree node. - */ - if (!of_graph_is_present(np)) - return -ENODEV; - - remote = of_graph_get_remote_node(np, port, endpoint); - -of_find_panel_or_bridge: - if (!remote) - return -ENODEV; - - if (panel) { - *panel = of_drm_find_panel(remote); - if (!IS_ERR(*panel)) - ret = 0; - else - *panel = NULL; - } + /* Otherwise check for any child node other than port/ports. */ + for_each_available_child_of_node(np, node) { + if (of_node_name_eq(node, "port") || + of_node_name_eq(node, "ports")) + continue;

- /* No panel found yet, check for a bridge next. */ - if (bridge) { - if (ret) { - *bridge = of_drm_find_bridge(remote); - if (*bridge) - ret = 0; - } else { - *bridge = NULL; - } + ret = find_panel_or_bridge(node, panel, bridge); + of_node_put(node);

+ /* Stop at the first found occurrence. */ + if (!ret) + return 0; }

- of_node_put(remote); - return ret; + return -EPROBE_DEFER; } EXPORT_SYMBOL_GPL(drm_of_find_panel_or_bridge);