NVMEM

Non-volatile memory cells. More...

Topics
	NVMEM Devicetree Helpers
	Devicetree support for NVMEM.

Files
file	nvmem.h
	Public NVMEM header file.

Data Structures
struct	nvmem_cell
	Non-Volatile Memory cell representation. More...

Macros
#define	NVMEM_CELL_INIT(node_id)
	Get a static initializer for a struct nvmem_cell.
#define	NVMEM_CELL_GET_BY_NAME(node_id, name)
	Get a static initializer for a struct nvmem_cell by name.
#define	NVMEM_CELL_INST_GET_BY_NAME(inst, name)
	Get a static initializer for a struct nvmem_cell from a DT_DRV_COMPAT instance by name.
#define	NVMEM_CELL_GET_BY_NAME_OR(node_id, name, default_value)
	Get a static initializer for a struct nvmem_cell by name, with a fallback.
#define	NVMEM_CELL_INST_GET_BY_NAME_OR(inst, name, default_value)
	Get a static initializer for a struct nvmem_cell from a DT_DRV_COMPAT instance by name, with a fallback.
#define	NVMEM_CELL_GET_BY_IDX(node_id, idx)
	Get a static initializer for a struct nvmem_cell by index.
#define	NVMEM_CELL_INST_GET_BY_IDX(inst, idx)
	Get a static initializer for a struct nvmem_cell from a DT_DRV_COMPAT instance by index.
#define	NVMEM_CELL_GET_BY_IDX_OR(node_id, idx, default_value)
	Get a static initializer for a struct nvmem_cell by index, with a fallback.
#define	NVMEM_CELL_INST_GET_BY_IDX_OR(inst, idx, default_value)
	Get a static initializer for a struct nvmem_cell from a DT_DRV_COMPAT instance by index, with a fallback.

Functions
int	nvmem_cell_read (const struct nvmem_cell *cell, void *data, off_t off, size_t len)
	Read data from an NVMEM cell.
int	nvmem_cell_write (const struct nvmem_cell *cell, const void *data, off_t off, size_t len)
	Write data to an NVMEM cell.
static bool	nvmem_cell_is_ready (const struct nvmem_cell *cell)
	Check if an NVMEM cell is ready.

Detailed Description

Non-volatile memory cells.

Since

4.3

Version

0.1.0

Macro Definition Documentation

NVMEM_CELL_GET_BY_IDX

#define NVMEM_CELL_GET_BY_IDX	(		node_id,
			idx )

#include <zephyr/nvmem.h>

Value:

NVMEM_CELL_INIT(DT_NVMEM_CELL_BY_IDX(node_id, idx))

Get a static initializer for a struct nvmem_cell by index.

This returns a static initializer for a struct nvmem_cell given a devicetree node identifier and an index.

Example devicetree fragment:

mac_eeprom: mac_eeprom@2 {
   nvmem-layout {
           compatible = "fixed-layout";
           #address-cells = <1>;
           #size-cells = <1>;
 
           mac_address: mac_address@fa {
                   reg = <0xfa 0x06>;
                   #nvmem-cell-cells = <0>;
           };
   };
};
 
eth: ethernet {
   nvmem-cells = <&mac_address>;
   nvmem-cell-names = "mac-address";
};

Example usage:

const struct nvmem_cell cell =
   NVMEM_CELL_GET_BY_IDX(DT_NODELABEL(eth), 0);
 
// Initializes 'cell' to:
// {
// .dev = DEVICE_DT_GET(DT_NODELABEL(mac_eeprom)),
// .offset = 0xfa,
// .size = 6,
// .read_only = false,
// }

Parameters

node_id	Node identifier for a node with an nvmem-cells property.
idx	Logical index into 'nvmem-cells' property.

Returns

Static initializer for a struct nvmem_cell for the property.

See also

NVMEM_CELL_INST_GET_BY_IDX

NVMEM_CELL_GET_BY_IDX_OR

#define NVMEM_CELL_GET_BY_IDX_OR	(		node_id,
			idx,
			default_value )

#include <zephyr/nvmem.h>

Value:

        COND_CODE_1(DT_PROP_HAS_IDX(node_id, nvmem_cells, idx),                                    \
                    (NVMEM_CELL_GET_BY_IDX(node_id, idx)),                                         \
                    (default_value))

Get a static initializer for a struct nvmem_cell by index, with a fallback.

If the devicetree node identifier 'node_id' refers to a node with a property 'nvmem-cells', this expands to NVMEM_CELL_GET_BY_IDX(node_id, idx). The default_value parameter is not expanded in this case. Otherwise, this expands to default_value.

Parameters

node_id	Node identifier for a node that may have an nvmem-cells property.
idx	Logical index into 'nvmem-cells' property.
default_value	Fallback value to expand to.

Returns

Static initializer for a struct nvmem_cell for the property, or default_value if the node or property do not exist.

See also

NVMEM_CELL_INST_GET_BY_IDX_OR

NVMEM_CELL_GET_BY_NAME

#define NVMEM_CELL_GET_BY_NAME	(		node_id,
			name )

#include <zephyr/nvmem.h>

Value:

NVMEM_CELL_INIT(DT_NVMEM_CELL_BY_NAME(node_id, name))

Get a static initializer for a struct nvmem_cell by name.

This returns a static initializer for a struct nvmem_cell given a devicetree node identifier and a name.

Example devicetree fragment:

mac_eeprom: mac_eeprom@2 {
   nvmem-layout {
           compatible = "fixed-layout";
           #address-cells = <1>;
           #size-cells = <1>;
 
           mac_address: mac_address@fa {
                   reg = <0xfa 0x06>;
                   #nvmem-cell-cells = <0>;
           };
   };
};
 
eth: ethernet {
   nvmem-cells = <&mac_address>;
   nvmem-cell-names = "mac-address";
};

Example usage:

const struct nvmem_cell cell =
   NVMEM_CELL_GET_BY_NAME(DT_NODELABEL(eth), mac_address);
 
// Initializes 'cell' to:
// {
// .dev = DEVICE_DT_GET(DT_NODELABEL(mac_eeprom)),
// .offset = 0xfa,
// .size = 6,
// .read_only = false,
// }

Parameters

node_id	Node identifier for a node with an nvmem-cells property.
name	Lowercase-and-underscores name of an nvmem-cells element as defined by the node's nvmem-cell-names property.

Returns

Static initializer for a struct nvmem_cell for the property.

See also

NVMEM_CELL_INST_GET_BY_NAME

NVMEM_CELL_GET_BY_NAME_OR

#define NVMEM_CELL_GET_BY_NAME_OR	(		node_id,
			name,
			default_value )

#include <zephyr/nvmem.h>

Value:

        COND_CODE_1(DT_PROP_HAS_NAME(node_id, nvmem_cells, name),                                  \
                    (NVMEM_CELL_GET_BY_NAME(node_id, name)),                                       \
                    (default_value))

Get a static initializer for a struct nvmem_cell by name, with a fallback.

If the devicetree node identifier 'node_id' refers to a node with a property 'nvmem-cells', this expands to NVMEM_CELL_GET_BY_NAME(node_id, name). The default_value parameter is not expanded in this case. Otherwise, this expands to default_value.

Parameters

node_id	Node identifier for a node that may have an nvmem-cells property.
name	Lowercase-and-underscores name of an nvmem-cells element as defined by the node's nvmem-cell-names property.
default_value	Fallback value to expand to.

Returns

Static initializer for a struct nvmem_cell for the property, or default_value if the node or property do not exist.

See also

NVMEM_CELL_INST_GET_BY_NAME_OR

NVMEM_CELL_INIT

#define NVMEM_CELL_INIT

(

node_id

)

#include <zephyr/nvmem.h>

Value:

        {                                                                                          \
                .dev = DEVICE_DT_GET(DT_MTD_FROM_NVMEM_CELL(node_id)),                             \
                .offset = DT_REG_ADDR(node_id),                                                    \
                .size = DT_REG_SIZE(node_id),                                                      \
                .read_only = DT_PROP(node_id, read_only),                                          \
        }

Get a static initializer for a struct nvmem_cell.

This returns a static initializer for a struct nvmem_cell given a devicetree node identifier.

Note

This is a helper macro for other NVMEM_CELL_GET macros to initialize the nvmem_cell struct.

Example devicetree fragment:

mac_eeprom: mac_eeprom@2 {
   nvmem-layout {
           compatible = "fixed-layout";
           #address-cells = <1>;
           #size-cells = <1>;
 
           mac_address: mac_address@fa {
                   reg = <0xfa 0x06>;
                   #nvmem-cell-cells = <0>;
           };
   };
};

Example usage:

const struct nvmem_cell cell = NVMEM_CELL_INIT(DT_NODELABEL(mac_address));
 
// Initializes 'cell' to:
// {
// .dev = DEVICE_DT_GET(DT_NODELABEL(mac_eeprom)),
// .offset = 0xfa,
// .size = 6,
// .read_only = false,
// }

Parameters

node_id

Node identifier for an NVMEM cell.

Returns

Static initializer for a struct nvmem_cell

NVMEM_CELL_INST_GET_BY_IDX

#define NVMEM_CELL_INST_GET_BY_IDX	(		inst,
			idx )

#include <zephyr/nvmem.h>

Value:

NVMEM_CELL_GET_BY_IDX(DT_DRV_INST(inst), idx)

Get a static initializer for a struct nvmem_cell from a DT_DRV_COMPAT instance by index.

Parameters

inst	DT_DRV_COMPAT instance number.
idx	Logical index into 'nvmem-cells' property.

Returns

Static initializer for a struct nvmem_cell for the property.

See also

NVMEM_CELL_GET_BY_IDX

NVMEM_CELL_INST_GET_BY_IDX_OR

#define NVMEM_CELL_INST_GET_BY_IDX_OR	(		inst,
			idx,
			default_value )

#include <zephyr/nvmem.h>

Value:

        NVMEM_CELL_GET_BY_IDX_OR(DT_DRV_INST(inst), idx, default_value)

Get a static initializer for a struct nvmem_cell from a DT_DRV_COMPAT instance by index, with a fallback.

Parameters

inst	DT_DRV_COMPAT instance number.
idx	Logical index into 'nvmem-cells' property.
default_value	Fallback value to expand to.

Returns

Static initializer for a struct nvmem_cell for the property, or default_value if the node or property do not exist.

See also

NVMEM_CELL_GET_BY_IDX_OR

NVMEM_CELL_INST_GET_BY_NAME

#define NVMEM_CELL_INST_GET_BY_NAME	(		inst,
			name )

#include <zephyr/nvmem.h>

Value:

NVMEM_CELL_GET_BY_NAME(DT_DRV_INST(inst), name)

Get a static initializer for a struct nvmem_cell from a DT_DRV_COMPAT instance by name.

Parameters

inst	DT_DRV_COMPAT instance number.
name	Lowercase-and-underscores name of an nvmem-cells element as defined by the node's nvmem-cell-names property.

Returns

Static initializer for a struct nvmem_cell for the property.

See also

NVMEM_CELL_GET_BY_NAME

NVMEM_CELL_INST_GET_BY_NAME_OR

#define NVMEM_CELL_INST_GET_BY_NAME_OR	(		inst,
			name,
			default_value )

#include <zephyr/nvmem.h>

Value:

        NVMEM_CELL_GET_BY_NAME_OR(DT_DRV_INST(inst), name, default_value)

Get a static initializer for a struct nvmem_cell from a DT_DRV_COMPAT instance by name, with a fallback.

Parameters

inst	DT_DRV_COMPAT instance number.
name	Lowercase-and-underscores name of an nvmem-cells element as defined by the node's nvmem-cell-names property.
default_value	Fallback value to expand to.

Returns

Static initializer for a struct nvmem_cell for the property, or default_value if the node or property do not exist.

See also

NVMEM_CELL_GET_BY_NAME_OR

Function Documentation

nvmem_cell_is_ready()

bool nvmem_cell_is_ready ( const struct nvmem_cell * cell )

inlinestatic

#include <zephyr/nvmem.h>

Check if an NVMEM cell is ready.

Parameters

cell	NVMEM cell to check. May be NULL.

Returns

True if the NVMEM cell is ready for use and false otherwise.

nvmem_cell_read()

int nvmem_cell_read	(	const struct nvmem_cell *	cell,
		void *	data,
		off_t	off,
		size_t	len )

#include <zephyr/nvmem.h>

Read data from an NVMEM cell.

Parameters

	cell	NVMEM cell to read from.
[out]	data	Buffer to store the read data. Must be at least len bytes.
	off	Offset within the cell to start reading from, in bytes. Must be less than the cell size.
	len	Number of bytes to read. off + len must not exceed the cell size.

Attention

Available only when the following Kconfig option is enabled: CONFIG_NVMEM.

Return values

-EINVAL	Invalid offset or length arguments.
-ENODEV	The controller device is not ready.
-ENXIO	No runtime device API available.

Returns

The result of the underlying device API call.

nvmem_cell_write()

int nvmem_cell_write	(	const struct nvmem_cell *	cell,
		const void *	data,
		off_t	off,
		size_t	len )

#include <zephyr/nvmem.h>

Write data to an NVMEM cell.

Parameters

cell	NVMEM cell to write to. Must not be read-only.
data	Buffer containing data to write. Must be at least len bytes.
off	Offset within the cell to start writing to, in bytes. Must be less than the cell size.
len	Number of bytes to write. off + len must not exceed the cell size.

Attention

Available only when the following Kconfig option is enabled: CONFIG_NVMEM.

Return values

-EINVAL	Invalid offset or length arguments.
-EROFS	Writing to a read-only NVMEM Cell.
-ENODEV	The controller device is not ready.
-ENXIO	No runtime device API available.

Returns

The result of the underlying device API call.