[PATCH] mtd: Ensure NVMEM layouts get their of_node

[Miquel Raynal]

All the nvmem-layouts logic expects an of_node to be available. When mtd
started registering nvmem devices, the exact exposure was not yet
decided and thus the no_of_node field was set to 1 to avoid exposing
"too much". This has been lowered since we want children nodes of mtd
devices with the "nvmem-cells" compatible to be actually registered in
NVMEM. This is now also the case of the nvmem-layout containers.

Signed-off-by: Miquel Raynal <miquel.raynal at bootlin.com>
---
 drivers/mtd/mtdcore.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
index 061745acb9a7..60b670c42be5 100644
--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -543,6 +543,13 @@ static int mtd_nvmem_reg_read(void *priv, unsigned int offset,
 	return retlen == bytes ? 0 : -EIO;
 }
 
+static bool mtd_contains_nvmem_layout(struct mtd_info *mtd)
+{
+	/* of_find_node_by_name() calls of_node_put() on the starting node */
+	of_node_get(mtd->dev.of_node);
+	return of_find_node_by_name(mtd->dev.of_node, "nvmem-layout");
+}
+
 static int mtd_nvmem_add(struct mtd_info *mtd)
 {
 	struct device_node *node = mtd_get_of_node(mtd);
@@ -559,7 +566,8 @@ static int mtd_nvmem_add(struct mtd_info *mtd)
 	config.read_only = true;
 	config.root_only = true;
 	config.ignore_wp = true;
-	config.no_of_node = !of_device_is_compatible(node, "nvmem-cells");
+	config.no_of_node = !of_device_is_compatible(node, "nvmem-cells") ||
+			    !mtd_contains_nvmem_layout(mtd);
 	config.priv = mtd;
 
 	mtd->nvmem = nvmem_register(&config);
-- 
2.34.1