[PATCH v3] of: overlay: log the error cause on resolver failure

[Luca Ceresoli]

When a DT overlay has a node label that is not present in the live
devicetree symbols table, this error is printed:

  OF: resolver: overlay phandle fixup failed: -22
  create_overlay: Failed to create overlay (err=-22)

which does not help much in finding the node label that caused the problem
and fix the overlay source.

Add an error message with the name of the node label that caused the
error. The new output is:

  OF: resolver: node label 'gpio9' not found in live devicetree symbols table
  OF: resolver: overlay phandle fixup failed: -22
  create_overlay: Failed to create overlay (err=-22)

Signed-off-by: Luca Ceresoli <luca@xxxxxxxxxxxxxxxx>

---

Changed in v3:
 - add only the message from v1, but as reworded by Frank

Changed in v2:
 - add a message for each error path that does not have one yet
---
 drivers/of/resolver.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/of/resolver.c b/drivers/of/resolver.c
index 83c766233181..b278ab4338ce 100644
--- a/drivers/of/resolver.c
+++ b/drivers/of/resolver.c
@@ -321,8 +321,11 @@ int of_resolve_phandles(struct device_node *overlay)
 
 		err = of_property_read_string(tree_symbols,
 				prop->name, &refpath);
-		if (err)
+		if (err) {
+			pr_err("node label '%s' not found in live devicetree symbols table\n",
+			       prop->name);
 			goto out;
+		}
 
 		refnode = of_find_node_by_path(refpath);
 		if (!refnode) {
-- 
2.25.1