linux-kernel - [PATCH v5 2/6] drm: rcar-du: lvds: Improve identification of panels

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Message-Id: <1576527154-18391-3-git-send-email-fabrizio.castro@bp.renesas.com>
Date:   Mon, 16 Dec 2019 20:12:30 +0000
From:   Fabrizio Castro <fabrizio.castro@...renesas.com>
To:     Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Thierry Reding <thierry.reding@...il.com>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Sean Paul <sean@...rly.run>,
        Andrzej Hajda <a.hajda@...sung.com>
Cc:     Fabrizio Castro <fabrizio.castro@...renesas.com>,
        Sam Ravnborg <sam@...nborg.org>,
        Simon Horman <horms@...ge.net.au>,
        Magnus Damm <magnus.damm@...il.com>,
        Kieran Bingham <kieran.bingham+renesas@...asonboard.com>,
        dri-devel@...ts.freedesktop.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-renesas-soc@...r.kernel.org,
        Chris Paterson <Chris.Paterson2@...esas.com>,
        Biju Das <biju.das@...renesas.com>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Jacopo Mondi <jacopo+renesas@...ndi.org>,
        ebiharaml@...linux.co.jp
Subject: [PATCH v5 2/6] drm: rcar-du: lvds: Improve identification of panels

Dual-LVDS panels are mistakenly identified as bridges, this
commit replaces the current logic with a call to
drm_of_find_panel_or_bridge to sort that out.

Signed-off-by: Fabrizio Castro <fabrizio.castro@...renesas.com>

---
v4->v5:
* Addressed comments from Laurent's review

v3->v4:
* New patch extracted from patch:
  "drm: rcar-du: lvds: Add dual-LVDS panels support"
---
 drivers/gpu/drm/rcar-du/rcar_lvds.c | 75 +++++--------------------------------
 1 file changed, 10 insertions(+), 65 deletions(-)

diff --git a/drivers/gpu/drm/rcar-du/rcar_lvds.c b/drivers/gpu/drm/rcar-du/rcar_lvds.c
index b03b7cd..4d038bd 100644
--- a/drivers/gpu/drm/rcar-du/rcar_lvds.c
+++ b/drivers/gpu/drm/rcar-du/rcar_lvds.c
@@ -21,6 +21,7 @@
 #include <drm/drm_atomic.h>
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_bridge.h>
+#include <drm/drm_of.h>
 #include <drm/drm_panel.h>
 #include <drm/drm_probe_helper.h>
 
@@ -716,79 +717,23 @@ static int rcar_lvds_parse_dt_companion(struct rcar_lvds *lvds)
 
 static int rcar_lvds_parse_dt(struct rcar_lvds *lvds)
 {
-	struct device_node *local_output = NULL;
-	struct device_node *remote_input = NULL;
-	struct device_node *remote = NULL;
-	struct device_node *node;
-	bool is_bridge = false;
-	int ret = 0;
-
-	local_output = of_graph_get_endpoint_by_regs(lvds->dev->of_node, 1, 0);
-	if (!local_output) {
-		dev_dbg(lvds->dev, "unconnected port@1\n");
-		ret = -ENODEV;
-		goto done;
-	}
-
-	/*
-	 * Locate the connected entity and infer its type from the number of
-	 * endpoints.
-	 */
-	remote = of_graph_get_remote_port_parent(local_output);
-	if (!remote) {
-		dev_dbg(lvds->dev, "unconnected endpoint %pOF\n", local_output);
-		ret = -ENODEV;
-		goto done;
-	}
+	int ret;
 
-	if (!of_device_is_available(remote)) {
-		dev_dbg(lvds->dev, "connected entity %pOF is disabled\n",
-			remote);
-		ret = -ENODEV;
+	ret = drm_of_find_panel_or_bridge(lvds->dev->of_node, 1, 0,
+					  &lvds->panel, &lvds->next_bridge);
+	if (ret)
 		goto done;
-	}
 
-	remote_input = of_graph_get_remote_endpoint(local_output);
-
-	for_each_endpoint_of_node(remote, node) {
-		if (node != remote_input) {
-			/*
-			 * We've found one endpoint other than the input, this
-			 * must be a bridge.
-			 */
-			is_bridge = true;
-			of_node_put(node);
-			break;
-		}
-	}
-
-	if (is_bridge) {
-		lvds->next_bridge = of_drm_find_bridge(remote);
-		if (!lvds->next_bridge) {
-			ret = -EPROBE_DEFER;
-			goto done;
-		}
-
-		if (lvds->info->quirks & RCAR_LVDS_QUIRK_DUAL_LINK)
-			lvds->dual_link = lvds->next_bridge->timings
-					? lvds->next_bridge->timings->dual_link
-					: false;
-	} else {
-		lvds->panel = of_drm_find_panel(remote);
-		if (IS_ERR(lvds->panel)) {
-			ret = PTR_ERR(lvds->panel);
-			goto done;
-		}
-	}
+	if ((lvds->info->quirks & RCAR_LVDS_QUIRK_DUAL_LINK) &&
+	    lvds->next_bridge)
+		lvds->dual_link = lvds->next_bridge->timings
+				? lvds->next_bridge->timings->dual_link
+				: false;
 
 	if (lvds->dual_link)
 		ret = rcar_lvds_parse_dt_companion(lvds);
 
 done:
-	of_node_put(local_output);
-	of_node_put(remote_input);
-	of_node_put(remote);
-
 	/*
 	 * On D3/E3 the LVDS encoder provides a clock to the DU, which can be
 	 * used for the DPAD output even when the LVDS output is not connected.
-- 
2.7.4