diff mbox series

[V4,1/2] mtd: allow getting MTD device associated with a specific DT node

Message ID 20220615194300.13358-1-zajec5@gmail.com (mailing list archive)
State New, archived
Headers show
Series [V4,1/2] mtd: allow getting MTD device associated with a specific DT node | expand

Commit Message

Rafał Miłecki June 15, 2022, 7:42 p.m. UTC
From: Rafał Miłecki <rafal@milecki.pl>

MTD subsystem API allows interacting with MTD devices (e.g. reading,
writing, handling bad blocks). So far a random driver could get MTD
device only by its name (get_mtd_device_nm()). This change allows
getting them also by a DT node.

This API is required for drivers handling DT defined MTD partitions in a
specific way (e.g. U-Boot (sub)partition with environment variables).

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Acked-by: Miquel Raynal <miquel.raynal@bootlin.com>
---
V3: First introduction of of_get_mtd_device_by_node()
V4: Use EPROBE_DEFER

Srinivas: in V3 Miquel said it's OK to push this patch through NVMEM 
---
 drivers/mtd/mtdcore.c   | 28 ++++++++++++++++++++++++++++
 include/linux/mtd/mtd.h |  1 +
 2 files changed, 29 insertions(+)

Comments

Ahmad Fatoum June 17, 2022, 7 a.m. UTC | #1
On 15.06.22 21:42, Rafał Miłecki wrote:
> From: Rafał Miłecki <rafal@milecki.pl>
> 
> MTD subsystem API allows interacting with MTD devices (e.g. reading,
> writing, handling bad blocks). So far a random driver could get MTD
> device only by its name (get_mtd_device_nm()). This change allows
> getting them also by a DT node.
> 
> This API is required for drivers handling DT defined MTD partitions in a
> specific way (e.g. U-Boot (sub)partition with environment variables).
> 
> Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
> Acked-by: Miquel Raynal <miquel.raynal@bootlin.com>

Reviewed-by: Ahmad Fatoum <a.fatoum@pengutronix.de>

> ---
> V3: First introduction of of_get_mtd_device_by_node()
> V4: Use EPROBE_DEFER
> 
> Srinivas: in V3 Miquel said it's OK to push this patch through NVMEM 
> ---
>  drivers/mtd/mtdcore.c   | 28 ++++++++++++++++++++++++++++
>  include/linux/mtd/mtd.h |  1 +
>  2 files changed, 29 insertions(+)
> 
> diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
> index 9eb0680db312..3613cc142f25 100644
> --- a/drivers/mtd/mtdcore.c
> +++ b/drivers/mtd/mtdcore.c
> @@ -1154,6 +1154,34 @@ int __get_mtd_device(struct mtd_info *mtd)
>  }
>  EXPORT_SYMBOL_GPL(__get_mtd_device);
>  
> +/**
> + * of_get_mtd_device_by_node - obtain an MTD device associated with a given node
> + *
> + * @np: device tree node
> + */
> +struct mtd_info *of_get_mtd_device_by_node(struct device_node *np)
> +{
> +	struct mtd_info *mtd = NULL;
> +	struct mtd_info *tmp;
> +	int err;
> +
> +	mutex_lock(&mtd_table_mutex);
> +
> +	err = -EPROBE_DEFER;
> +	mtd_for_each_device(tmp) {
> +		if (mtd_get_of_node(tmp) == np) {
> +			mtd = tmp;
> +			err = __get_mtd_device(mtd);
> +			break;
> +		}
> +	}
> +
> +	mutex_unlock(&mtd_table_mutex);
> +
> +	return err ? ERR_PTR(err) : mtd;
> +}
> +EXPORT_SYMBOL_GPL(of_get_mtd_device_by_node);
> +
>  /**
>   *	get_mtd_device_nm - obtain a validated handle for an MTD device by
>   *	device name
> diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h
> index 955aee14b0f7..6fc841ceef31 100644
> --- a/include/linux/mtd/mtd.h
> +++ b/include/linux/mtd/mtd.h
> @@ -677,6 +677,7 @@ extern int mtd_device_unregister(struct mtd_info *master);
>  extern struct mtd_info *get_mtd_device(struct mtd_info *mtd, int num);
>  extern int __get_mtd_device(struct mtd_info *mtd);
>  extern void __put_mtd_device(struct mtd_info *mtd);
> +extern struct mtd_info *of_get_mtd_device_by_node(struct device_node *np);
>  extern struct mtd_info *get_mtd_device_nm(const char *name);
>  extern void put_mtd_device(struct mtd_info *mtd);
>
diff mbox series

Patch

diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
index 9eb0680db312..3613cc142f25 100644
--- a/drivers/mtd/mtdcore.c
+++ b/drivers/mtd/mtdcore.c
@@ -1154,6 +1154,34 @@  int __get_mtd_device(struct mtd_info *mtd)
 }
 EXPORT_SYMBOL_GPL(__get_mtd_device);
 
+/**
+ * of_get_mtd_device_by_node - obtain an MTD device associated with a given node
+ *
+ * @np: device tree node
+ */
+struct mtd_info *of_get_mtd_device_by_node(struct device_node *np)
+{
+	struct mtd_info *mtd = NULL;
+	struct mtd_info *tmp;
+	int err;
+
+	mutex_lock(&mtd_table_mutex);
+
+	err = -EPROBE_DEFER;
+	mtd_for_each_device(tmp) {
+		if (mtd_get_of_node(tmp) == np) {
+			mtd = tmp;
+			err = __get_mtd_device(mtd);
+			break;
+		}
+	}
+
+	mutex_unlock(&mtd_table_mutex);
+
+	return err ? ERR_PTR(err) : mtd;
+}
+EXPORT_SYMBOL_GPL(of_get_mtd_device_by_node);
+
 /**
  *	get_mtd_device_nm - obtain a validated handle for an MTD device by
  *	device name
diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h
index 955aee14b0f7..6fc841ceef31 100644
--- a/include/linux/mtd/mtd.h
+++ b/include/linux/mtd/mtd.h
@@ -677,6 +677,7 @@  extern int mtd_device_unregister(struct mtd_info *master);
 extern struct mtd_info *get_mtd_device(struct mtd_info *mtd, int num);
 extern int __get_mtd_device(struct mtd_info *mtd);
 extern void __put_mtd_device(struct mtd_info *mtd);
+extern struct mtd_info *of_get_mtd_device_by_node(struct device_node *np);
 extern struct mtd_info *get_mtd_device_nm(const char *name);
 extern void put_mtd_device(struct mtd_info *mtd);