target/linux/generic/pending-4.14/495-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 diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
  19 index e7ea842ba3db..1134bb81d2e5 100644
  20 --- a/drivers/mtd/mtdcore.c
  21 +++ b/drivers/mtd/mtdcore.c
  22 @@ -936,6 +936,44 @@ struct mtd_info *get_mtd_device_nm(const char *name)
  23  }
  24  EXPORT_SYMBOL_GPL(get_mtd_device_nm);
  25
  26 +/**
  27 + *     get_mtd_device_by_node - obtain a validated handle for an MTD device
  28 + *     by of_node
  29 + *     @of_node: OF node of MTD device to open
  30 + *
  31 + *     This function returns MTD device description structure in case of
  32 + *     success and an error code in case of failure.
  33 + */
  34 +struct mtd_info *get_mtd_device_by_node(const struct device_node *of_node)
  35 +{
  36 +       int err = -ENODEV;
  37 +       struct mtd_info *mtd = NULL, *other;
  38 +
  39 +       mutex_lock(&mtd_table_mutex);
  40 +
  41 +       mtd_for_each_device(other) {
  42 +               if (of_node == other->dev.of_node) {
  43 +                       mtd = other;
  44 +                       break;
  45 +               }
  46 +       }
  47 +
  48 +       if (!mtd)
  49 +               goto out_unlock;
  50 +
  51 +       err = __get_mtd_device(mtd);
  52 +       if (err)
  53 +               goto out_unlock;
  54 +
  55 +       mutex_unlock(&mtd_table_mutex);
  56 +       return mtd;
  57 +
  58 +out_unlock:
  59 +       mutex_unlock(&mtd_table_mutex);
  60 +       return ERR_PTR(err);
  61 +}
  62 +EXPORT_SYMBOL_GPL(get_mtd_device_by_node);
  63 +
  64  void put_mtd_device(struct mtd_info *mtd)
  65  {
  66         mutex_lock(&mtd_table_mutex);
  67 diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h
  68 index 6cd0f6b7658b..cf7c8030cd8e 100644
  69 --- a/include/linux/mtd/mtd.h
  70 +++ b/include/linux/mtd/mtd.h
  71 @@ -557,6 +557,8 @@ extern struct mtd_info *get_mtd_device(struct mtd_info *mtd, int num);
  72  extern int __get_mtd_device(struct mtd_info *mtd);
  73  extern void __put_mtd_device(struct mtd_info *mtd);
  74  extern struct mtd_info *get_mtd_device_nm(const char *name);
  75 +extern struct mtd_info *get_mtd_device_by_node(
  76 +               const struct device_node *of_node);
  77  extern void put_mtd_device(struct mtd_info *mtd);
  78
  79
  80 --
  81 2.18.0
  82