[PATCH v2] drm: rcar_lvds: Fix dual link mode operations

From: Jacopo Mondi
Date: Mon Aug 05 2019 - 12:17:30 EST

The R-Car LVDS encoder units support dual-link operations by splitting
the pixel output between the primary encoder and the companion one.

Currently the companion encoder fails at probe time, causing the
registration of the primary to fail as well, preventing the whole DU unit
from being registered at all.

Fix this by not bailing out from probe with error if the
"renesas,companion" property is not specified.

Fixes: fa440d870358 ("drm: rcar-du: lvds: Add support for dual-link mode")
Reported-by: Fabrizio Castro <fabrizio.castro@xxxxxxxxxxxxxx>
Signed-off-by: Jacopo Mondi <jacopo+renesas@xxxxxxxxxx>
drivers/gpu/drm/rcar-du/rcar_lvds.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/rcar-du/rcar_lvds.c b/drivers/gpu/drm/rcar-du/rcar_lvds.c
index bada7ee98544..0b872d00760b 100644
--- a/drivers/gpu/drm/rcar-du/rcar_lvds.c
+++ b/drivers/gpu/drm/rcar-du/rcar_lvds.c
@@ -662,10 +662,8 @@ static int rcar_lvds_parse_dt_companion(struct rcar_lvds *lvds)

/* Locate the companion LVDS encoder for dual-link operation, if any. */
companion = of_parse_phandle(dev->of_node, "renesas,companion", 0);
- if (!companion) {
- dev_err(dev, "Companion LVDS encoder not found\n");
- return -ENXIO;
- }
+ if (!companion)
+ return 0;

* Sanity check: the companion encoder must have the same compatible