target/linux/generic/pending-4.19/495-mtd-core-add-get_mtd_device_by_node.patch

   1 From 1bd1b740f208d1cf4071932cc51860d37266c402 Mon Sep 17 00:00:00 2001
   2 From: Bernhard Frauendienst <kernel@nospam.obeliks.de>
   3 Date: Sat, 1 Sep 2018 00:30:11 +0200
   4 Subject: [PATCH 495/497] mtd: core: add get_mtd_device_by_node
   5
   6 Add function to retrieve a mtd device by its OF node. Since drivers can
   7 assign arbitrary names to mtd devices in the absence of a label
   8 property, there is no other reliable way to retrieve a mtd device for a
   9 given OF node.
  10
  11 Signed-off-by: Bernhard Frauendienst <kernel@nospam.obeliks.de>
  12 Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
  13 ---
  14  drivers/mtd/mtdcore.c   | 38 ++++++++++++++++++++++++++++++++++++++
  15  include/linux/mtd/mtd.h |  2 ++
  16  2 files changed, 40 insertions(+)
  17
  18 --- a/drivers/mtd/mtdcore.c
  19 +++ b/drivers/mtd/mtdcore.c
  20 @@ -938,6 +938,44 @@ out_unlock:
  21  }
  22  EXPORT_SYMBOL_GPL(get_mtd_device_nm);
  23
  24 +/**
  25 + *     get_mtd_device_by_node - obtain a validated handle for an MTD device
  26 + *     by of_node
  27 + *     @of_node: OF node of MTD device to open
  28 + *
  29 + *     This function returns MTD device description structure in case of
  30 + *     success and an error code in case of failure.
  31 + */
  32 +struct mtd_info *get_mtd_device_by_node(const struct device_node *of_node)
  33 +{
  34 +       int err = -ENODEV;
  35 +       struct mtd_info *mtd = NULL, *other;
  36 +
  37 +       mutex_lock(&mtd_table_mutex);
  38 +
  39 +       mtd_for_each_device(other) {
  40 +               if (of_node == other->dev.of_node) {
  41 +                       mtd = other;
  42 +                       break;
  43 +               }
  44 +       }
  45 +
  46 +       if (!mtd)
  47 +               goto out_unlock;
  48 +
  49 +       err = __get_mtd_device(mtd);
  50 +       if (err)
  51 +               goto out_unlock;
  52 +
  53 +       mutex_unlock(&mtd_table_mutex);
  54 +       return mtd;
  55 +
  56 +out_unlock:
  57 +       mutex_unlock(&mtd_table_mutex);
  58 +       return ERR_PTR(err);
  59 +}
  60 +EXPORT_SYMBOL_GPL(get_mtd_device_by_node);
  61 +
  62  void put_mtd_device(struct mtd_info *mtd)
  63  {
  64         mutex_lock(&mtd_table_mutex);
  65 --- a/include/linux/mtd/mtd.h
  66 +++ b/include/linux/mtd/mtd.h
  67 @@ -589,6 +589,8 @@ extern struct mtd_info *get_mtd_device(s
  68  extern int __get_mtd_device(struct mtd_info *mtd);
  69  extern void __put_mtd_device(struct mtd_info *mtd);
  70  extern struct mtd_info *get_mtd_device_nm(const char *name);
  71 +extern struct mtd_info *get_mtd_device_by_node(
  72 +               const struct device_node *of_node);
  73  extern void put_mtd_device(struct mtd_info *mtd);
  74
  75