[PATCH v2 2/2] of: base: Improve argument length mismatch error

[Baruch Siach <baruch@tkos.co.il>]

The cells_name field of of_phandle_iterator might be NULL. Use the
phandle name instead. With this change instead of:

  OF: /soc/pinctrl@1000000: (null) = 3 found 2

We get:

  OF: /soc/pinctrl@1000000: phandle pinctrl@1000000 needs 3, found 2

Which is a more helpful messages making DT debugging easier.

In this particular example the phandle name looks like duplicate of the
same node name. But note that the first node is the parent node
(it->parent), while the second is the phandle target (it->node). They
happen to be the same in the case that triggered this improvement. See
commit 72cb4c48a46a ("arm64: dts: qcom: ipq6018: Fix gpio-ranges
property").

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
---
Note that commit 72cb4c48a46a mentioned above is currently in the
arm64-for-5.17 branch of the qcom git tree.

v2:

  Extend the commit log to explain the apparent node name duplication
---
 drivers/of/base.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index 81b956ab2348..09905b5e7b43 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -1349,9 +1349,14 @@ int of_phandle_iterator_next(struct of_phandle_iterator *it)
 		 * property data length
 		 */
 		if (it->cur + count > it->list_end) {
-			pr_err("%pOF: %s = %d found %td\n",
-			       it->parent, it->cells_name,
-			       count, it->list_end - it->cur);
+			if (it->cells_name)
+				pr_err("%pOF: %s = %d found %td\n",
+					it->parent, it->cells_name,
+					count, it->list_end - it->cur);
+			else
+				pr_err("%pOF: phandle %s needs %d, found %td\n",
+					it->parent, of_node_full_name(it->node),
+					count, it->list_end - it->cur);
 			goto err;
 		}
 	}
-- 
2.34.1