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From 1bd1b740f208d1cf4071932cc51860d37266c402 Mon Sep 17 00:00:00 2001
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From: Bernhard Frauendienst <kernel@nospam.obeliks.de>
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Date: Sat, 1 Sep 2018 00:30:11 +0200
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Subject: [PATCH 495/497] mtd: core: add get_mtd_device_by_node
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Add function to retrieve a mtd device by its OF node. Since drivers can
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assign arbitrary names to mtd devices in the absence of a label
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property, there is no other reliable way to retrieve a mtd device for a
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given OF node.
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Signed-off-by: Bernhard Frauendienst <kernel@nospam.obeliks.de>
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Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
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---
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drivers/mtd/mtdcore.c | 38 ++++++++++++++++++++++++++++++++++++++
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include/linux/mtd/mtd.h | 2 ++
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2 files changed, 40 insertions(+)
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--- a/drivers/mtd/mtdcore.c
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+++ b/drivers/mtd/mtdcore.c
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@@ -938,6 +938,44 @@ out_unlock:
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}
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EXPORT_SYMBOL_GPL(get_mtd_device_nm);
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+/**
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+ * get_mtd_device_by_node - obtain a validated handle for an MTD device
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+ * by of_node
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+ * @of_node: OF node of MTD device to open
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+ *
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+ * This function returns MTD device description structure in case of
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+ * success and an error code in case of failure.
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+ */
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+struct mtd_info *get_mtd_device_by_node(const struct device_node *of_node)
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+{
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+ int err = -ENODEV;
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+ struct mtd_info *mtd = NULL, *other;
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+
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+ mutex_lock(&mtd_table_mutex);
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+
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+ mtd_for_each_device(other) {
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+ if (of_node == other->dev.of_node) {
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+ mtd = other;
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+ break;
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+ }
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+ }
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+
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+ if (!mtd)
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+ goto out_unlock;
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+
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+ err = __get_mtd_device(mtd);
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+ if (err)
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+ goto out_unlock;
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+
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+ mutex_unlock(&mtd_table_mutex);
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+ return mtd;
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+
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+out_unlock:
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+ mutex_unlock(&mtd_table_mutex);
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+ return ERR_PTR(err);
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+}
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+EXPORT_SYMBOL_GPL(get_mtd_device_by_node);
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+
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void put_mtd_device(struct mtd_info *mtd)
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{
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mutex_lock(&mtd_table_mutex);
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--- a/include/linux/mtd/mtd.h
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+++ b/include/linux/mtd/mtd.h
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@@ -589,6 +589,8 @@ extern struct mtd_info *get_mtd_device(s
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extern int __get_mtd_device(struct mtd_info *mtd);
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extern void __put_mtd_device(struct mtd_info *mtd);
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extern struct mtd_info *get_mtd_device_nm(const char *name);
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+extern struct mtd_info *get_mtd_device_by_node(
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+ const struct device_node *of_node);
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extern void put_mtd_device(struct mtd_info *mtd);
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