Unverified Commit 67bae5f2 authored by Paul Kocialkowski's avatar Paul Kocialkowski Committed by Maxime Ripard
Browse files

drm: of: Properly try all possible cases for bridge/panel detection 



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: default avatarPaul Kocialkowski <paul.kocialkowski@bootlin.com>
Fixes: 80253168 ("drm: of: Lookup if child node has panel or bridge")
Signed-off-by: default avatarMaxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20220329132732.628474-1-paul.kocialkowski@bootlin.com
parent c42ee39c

drivers/gpu/drm/drm_of.c

+50 −49
Original line number Diff line number Diff line
@@ -219,6 +219,29 @@ 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;



		/* Clear the panel pointer in case of error. */

		*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 +264,44 @@ 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;

	if (bridge)

		*bridge = 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;

	/* 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);



		goto of_find_panel_or_bridge;

			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;

	}



	/* 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;

		}

	/* 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;



		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);