linux-kernel - [PATCH 2/2] Revert "drm: of: Lookup if child node has panel or bridge"

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Date:   Wed, 20 Apr 2022 16:12:30 -0700
From:   Bjorn Andersson <bjorn.andersson@...aro.org>
To:     Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Thierry Reding <thierry.reding@...il.com>,
        Paul Kocialkowski <paul.kocialkowski@...tlin.com>,
        Rob Clark <robdclark@...il.com>
Cc:     dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: [PATCH 2/2] Revert "drm: of: Lookup if child node has panel or bridge"

Commit '80253168dbfd ("drm: of: Lookup if child node has panel or
bridge")' attempted to simplify the case of expressing a simple panel
under a DSI controller, by assuming that the first non-graph child node
was a panel or bridge.

Unfortunately for non-trivial cases the first child node might not be a
panel or bridge.  Examples of this can be a aux-bus in the case of
DisplayPort, or an opp-table represented before the panel node.

In these cases the reverted commit prevents the caller from ever finding
a reference to the panel.

This reverts commit '80253168dbfd ("drm: of: Lookup if child node has
panel or bridge")', in favor of using an explicit graph reference to the
panel in the trivial case as well.

Signed-off-by: Bjorn Andersson <bjorn.andersson@...aro.org>
---
 drivers/gpu/drm/drm_of.c | 17 -----------------
 1 file changed, 17 deletions(-)

diff --git a/drivers/gpu/drm/drm_of.c b/drivers/gpu/drm/drm_of.c
index 026e4e29a0f3..9a2cfab3a177 100644
--- a/drivers/gpu/drm/drm_of.c
+++ b/drivers/gpu/drm/drm_of.c
@@ -244,21 +244,6 @@ int drm_of_find_panel_or_bridge(const struct device_node *np,
 	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;
-	}
-
 	/*
 	 * 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,
@@ -269,8 +254,6 @@ int drm_of_find_panel_or_bridge(const struct device_node *np,
 		return -ENODEV;
 
 	remote = of_graph_get_remote_node(np, port, endpoint);
-
-of_find_panel_or_bridge:
 	if (!remote)
 		return -ENODEV;
 
-- 
2.35.1