openwrt/target/linux/generic/backport-6.1/406-v6.2-0002-mtd-core-try-to-find-OF-node-for-every-MTD-partition.patch

From ddb8cefb7af288950447ca6eeeafb09977dab56f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <[email protected]>
Date: Tue, 4 Oct 2022 10:37:10 +0200
Subject: [PATCH] mtd: core: try to find OF node for every MTD partition
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So far this feature was limited to the top-level "nvmem-cells" node.
There are multiple parsers creating partitions and subpartitions
dynamically. Extend that code to handle them too.

This allows finding partition-* node for every MTD (sub)partition.

Random example:

partitions {
	compatible = "brcm,bcm947xx-cfe-partitions";

	partition-firmware {
		compatible = "brcm,trx";

		partition-loader {
		};
	};
};

Cc: Christian Marangi <[email protected]>
Signed-off-by: Rafał Miłecki <[email protected]>
Signed-off-by: Miquel Raynal <[email protected]>
Link: https://lore.kernel.org/linux-mtd/[email protected]
---
 drivers/mtd/mtdcore.c | 18 ++++++------------
 1 file changed, 6 insertions(+), 12 deletions(-)

--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -569,20 +569,22 @@ static void mtd_check_of_node(struct mtd
 	struct device_node *partitions, *parent_dn, *mtd_dn = NULL;
 	const char *pname, *prefix = "partition-";
 	int plen, mtd_name_len, offset, prefix_len;
-	bool found = false;
 
 	/* Check if MTD already has a device node */
 	if (mtd_get_of_node(mtd))
 		return;
 
-	/* Check if a partitions node exist */
 	if (!mtd_is_partition(mtd))
 		return;
+
 	parent_dn = of_node_get(mtd_get_of_node(mtd->parent));
 	if (!parent_dn)
 		return;
 
-	partitions = of_get_child_by_name(parent_dn, "partitions");
+	if (mtd_is_partition(mtd->parent))
+		partitions = of_node_get(parent_dn);
+	else
+		partitions = of_get_child_by_name(parent_dn, "partitions");
 	if (!partitions)
 		goto exit_parent;
 
@@ -606,19 +608,11 @@ static void mtd_check_of_node(struct mtd
 		plen = strlen(pname) - offset;
 		if (plen == mtd_name_len &&
 		    !strncmp(mtd->name, pname + offset, plen)) {
-			found = true;
+			mtd_set_of_node(mtd, mtd_dn);
 			break;
 		}
 	}
 
-	if (!found)
-		goto exit_partitions;
-
-	/* Set of_node only for nvmem */
-	if (of_device_is_compatible(mtd_dn, "nvmem-cells"))
-		mtd_set_of_node(mtd, mtd_dn);
-
-exit_partitions:
 	of_node_put(partitions);
 exit_parent:
 	of_node_put(parent_dn);