From 1bd1b740f208d1cf4071932cc51860d37266c402 Mon Sep 17 00:00:00 2001 From: Bernhard Frauendienst Date: Sat, 1 Sep 2018 00:30:11 +0200 Subject: [PATCH 495/497] mtd: core: add get_mtd_device_by_node 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 Reviewed-by: Miquel Raynal --- drivers/mtd/mtdcore.c | 38 ++++++++++++++++++++++++++++++++++++++ include/linux/mtd/mtd.h | 2 ++ 2 files changed, 40 insertions(+) --- a/drivers/mtd/mtdcore.c +++ b/drivers/mtd/mtdcore.c @@ -938,6 +938,44 @@ out_unlock: } 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); --- a/include/linux/mtd/mtd.h +++ b/include/linux/mtd/mtd.h @@ -589,6 +589,8 @@ extern struct mtd_info *get_mtd_device(s 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);