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Subject[PATCH v3 1/3] mtd: core: add get_mtd_device_by_node
Date
Add function to retrieve a mtd device by its OF node. Since drivers can
assign arbitrary names to mtd devices in the absence of a label
property, there is no other reliable way to retrieve a mtd device for a
given OF node.

Signed-off-by: Bernhard Frauendienst <kernel@nospam.obeliks.de>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
---
drivers/mtd/mtdcore.c | 38 ++++++++++++++++++++++++++++++++++++++
include/linux/mtd/mtd.h | 2 ++
2 files changed, 40 insertions(+)

diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
index 97ac219c082e..87dd63926bc9 100644
--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -926,6 +926,44 @@ struct mtd_info *get_mtd_device_nm(const char *name)
}
EXPORT_SYMBOL_GPL(get_mtd_device_nm);

+/**
+ * get_mtd_device_by_node - obtain a validated handle for an MTD device
+ * by of_node
+ * @of_node: OF node of MTD device to open
+ *
+ * This function returns MTD device description structure in case of
+ * success and an error code in case of failure.
+ */
+struct mtd_info *get_mtd_device_by_node(const struct device_node *of_node)
+{
+ int err = -ENODEV;
+ struct mtd_info *mtd = NULL, *other;
+
+ mutex_lock(&mtd_table_mutex);
+
+ mtd_for_each_device(other) {
+ if (of_node == other->dev.of_node) {
+ mtd = other;
+ break;
+ }
+ }
+
+ if (!mtd)
+ goto out_unlock;
+
+ err = __get_mtd_device(mtd);
+ if (err)
+ goto out_unlock;
+
+ mutex_unlock(&mtd_table_mutex);
+ return mtd;
+
+out_unlock:
+ mutex_unlock(&mtd_table_mutex);
+ return ERR_PTR(err);
+}
+EXPORT_SYMBOL_GPL(get_mtd_device_by_node);
+
void put_mtd_device(struct mtd_info *mtd)
{
mutex_lock(&mtd_table_mutex);
diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h
index cd0be91bdefa..fe71358f8eaa 100644
--- a/include/linux/mtd/mtd.h
+++ b/include/linux/mtd/mtd.h
@@ -570,6 +570,8 @@ extern struct mtd_info *get_mtd_device(struct mtd_info *mtd, int num);
extern int __get_mtd_device(struct mtd_info *mtd);
extern void __put_mtd_device(struct mtd_info *mtd);
extern struct mtd_info *get_mtd_device_nm(const char *name);
+extern struct mtd_info *get_mtd_device_by_node(
+ const struct device_node *of_node);
extern void put_mtd_device(struct mtd_info *mtd);


--
2.18.0
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