[PATCH 1/1] drm/panel: panel-simple: Add dev_err_probe if backlight could not be found

[Alexander Stein <alexander.stein@xxxxxxxxxxxxxxx>]

If the backlight node is not enabled, this (silently) returns with
-EPROBE_DEFER. /sys/kernel/debug/devices_deferred also shows nothing
helpful:
$ cat /sys/kernel/debug/devices_deferred
display

With this patch, there is a helpful hint:
$ cat /sys/kernel/debug/devices_deferred
display panel-simple: Could not find backlight

Signed-off-by: Alexander Stein <alexander.stein@xxxxxxxxxxxxxxx>
---
 drivers/gpu/drm/panel/panel-simple.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/panel/panel-simple.c b/drivers/gpu/drm/panel/panel-simple.c
index 4a2e580a2f7b..8fb1c563c96a 100644
--- a/drivers/gpu/drm/panel/panel-simple.c
+++ b/drivers/gpu/drm/panel/panel-simple.c
@@ -663,8 +663,10 @@ static int panel_simple_probe(struct device *dev, const struct panel_desc *desc)
 	drm_panel_init(&panel->base, dev, &panel_simple_funcs, connector_type);
 
 	err = drm_panel_of_backlight(&panel->base);
-	if (err)
+	if (err) {
+		dev_err_probe(dev, err, "Could not find backlight\n");
 		goto disable_pm_runtime;
+	}
 
 	drm_panel_add(&panel->base);
 
-- 
2.25.1