target/linux/generic/backport-5.10/414-v6.1-mtd-allow-getting-MTD-device-associated-with-a-speci.patch

   1 From b0321721be50b80c03a51866a94fde4f94690e18 Mon Sep 17 00:00:00 2001
   2 From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
   3 Date: Wed, 15 Jun 2022 21:42:59 +0200
   4 Subject: [PATCH] mtd: allow getting MTD device associated with a specific DT
   5  node
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   9
  10 MTD subsystem API allows interacting with MTD devices (e.g. reading,
  11 writing, handling bad blocks). So far a random driver could get MTD
  12 device only by its name (get_mtd_device_nm()). This change allows
  13 getting them also by a DT node.
  14
  15 This API is required for drivers handling DT defined MTD partitions in a
  16 specific way (e.g. U-Boot (sub)partition with environment variables).
  17
  18 Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
  19 Acked-by: Miquel Raynal <miquel.raynal@bootlin.com>
  20 Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
  21 ---
  22  drivers/mtd/mtdcore.c   | 28 ++++++++++++++++++++++++++++
  23  include/linux/mtd/mtd.h |  1 +
  24  2 files changed, 29 insertions(+)
  25
  26 --- a/drivers/mtd/mtdcore.c
  27 +++ b/drivers/mtd/mtdcore.c
  28 @@ -1070,6 +1070,34 @@ int __get_mtd_device(struct mtd_info *mt
  29  EXPORT_SYMBOL_GPL(__get_mtd_device);
  30
  31  /**
  32 + * of_get_mtd_device_by_node - obtain an MTD device associated with a given node
  33 + *
  34 + * @np: device tree node
  35 + */
  36 +struct mtd_info *of_get_mtd_device_by_node(struct device_node *np)
  37 +{
  38 +       struct mtd_info *mtd = NULL;
  39 +       struct mtd_info *tmp;
  40 +       int err;
  41 +
  42 +       mutex_lock(&mtd_table_mutex);
  43 +
  44 +       err = -EPROBE_DEFER;
  45 +       mtd_for_each_device(tmp) {
  46 +               if (mtd_get_of_node(tmp) == np) {
  47 +                       mtd = tmp;
  48 +                       err = __get_mtd_device(mtd);
  49 +                       break;
  50 +               }
  51 +       }
  52 +
  53 +       mutex_unlock(&mtd_table_mutex);
  54 +
  55 +       return err ? ERR_PTR(err) : mtd;
  56 +}
  57 +EXPORT_SYMBOL_GPL(of_get_mtd_device_by_node);
  58 +
  59 +/**
  60   *     get_mtd_device_nm - obtain a validated handle for an MTD device by
  61   *     device name
  62   *     @name: MTD device name to open
  63 --- a/include/linux/mtd/mtd.h
  64 +++ b/include/linux/mtd/mtd.h
  65 @@ -675,6 +675,7 @@ extern int mtd_device_unregister(struct
  66  extern struct mtd_info *get_mtd_device(struct mtd_info *mtd, int num);
  67  extern int __get_mtd_device(struct mtd_info *mtd);
  68  extern void __put_mtd_device(struct mtd_info *mtd);
  69 +extern struct mtd_info *of_get_mtd_device_by_node(struct device_node *np);
  70  extern struct mtd_info *get_mtd_device_nm(const char *name);
  71  extern void put_mtd_device(struct mtd_info *mtd);
  72