linux-stable/include/linux/nvmem-provider.h

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/* SPDX-License-Identifier: GPL-2.0 */
/*
* nvmem framework provider.
*
* Copyright (C) 2015 Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
* Copyright (C) 2013 Maxime Ripard <maxime.ripard@free-electrons.com>
*/
#ifndef _LINUX_NVMEM_PROVIDER_H
#define _LINUX_NVMEM_PROVIDER_H
#include <linux/device/driver.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/gpio/consumer.h>
struct nvmem_device;
typedef int (*nvmem_reg_read_t)(void *priv, unsigned int offset,
void *val, size_t bytes);
typedef int (*nvmem_reg_write_t)(void *priv, unsigned int offset,
void *val, size_t bytes);
/* used for vendor specific post processing of cell data */
typedef int (*nvmem_cell_post_process_t)(void *priv, const char *id, int index,
unsigned int offset, void *buf,
size_t bytes);
enum nvmem_type {
NVMEM_TYPE_UNKNOWN = 0,
NVMEM_TYPE_EEPROM,
NVMEM_TYPE_OTP,
NVMEM_TYPE_BATTERY_BACKED,
NVMEM_TYPE_FRAM,
};
#define NVMEM_DEVID_NONE (-1)
#define NVMEM_DEVID_AUTO (-2)
/**
* struct nvmem_keepout - NVMEM register keepout range.
*
* @start: The first byte offset to avoid.
* @end: One beyond the last byte offset to avoid.
* @value: The byte to fill reads with for this region.
*/
struct nvmem_keepout {
unsigned int start;
unsigned int end;
unsigned char value;
};
/**
* struct nvmem_cell_info - NVMEM cell description
* @name: Name.
* @offset: Offset within the NVMEM device.
nvmem: core: support specifying both: cell raw data & post read lengths Callback .read_post_process() is designed to modify raw cell content before providing it to the consumer. So far we were dealing with modifications that didn't affect cell size (length). In some cases however cell content needs to be reformatted and resized. It's required e.g. to provide properly formatted MAC address in case it's stored in a non-binary format (e.g. using ASCII). There were few discussions how to optimally handle that. Following possible solutions were considered: 1. Allow .read_post_process() to realloc (resize) content buffer 2. Allow .read_post_process() to adjust (decrease) just buffer length 3. Register NVMEM cells using post-read sizes The preferred solution was the last one. The problem is that simply adjusting "bytes" in NVMEM providers would result in core code NOT passing whole raw data to .read_post_process() callbacks. It means callback functions couldn't do their job without somehow manually reading original cell content on their own. This patch deals with that by registering NVMEM cells with both lengths: raw content one and post read one. It allows: 1. Core code to read whole raw cell content 2. Callbacks to return content they want Signed-off-by: Rafał Miłecki <rafal@milecki.pl> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> Link: https://lore.kernel.org/r/20230404172148.82422-35-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-04-04 17:21:42 +00:00
* @raw_len: Length of raw data (without post processing).
* @bytes: Length of the cell.
* @bit_offset: Bit offset if cell is smaller than a byte.
* @nbits: Number of bits.
* @np: Optional device_node pointer.
* @read_post_process: Callback for optional post processing of cell data
* on reads.
* @priv: Opaque data passed to the read_post_process hook.
*/
struct nvmem_cell_info {
const char *name;
unsigned int offset;
nvmem: core: support specifying both: cell raw data & post read lengths Callback .read_post_process() is designed to modify raw cell content before providing it to the consumer. So far we were dealing with modifications that didn't affect cell size (length). In some cases however cell content needs to be reformatted and resized. It's required e.g. to provide properly formatted MAC address in case it's stored in a non-binary format (e.g. using ASCII). There were few discussions how to optimally handle that. Following possible solutions were considered: 1. Allow .read_post_process() to realloc (resize) content buffer 2. Allow .read_post_process() to adjust (decrease) just buffer length 3. Register NVMEM cells using post-read sizes The preferred solution was the last one. The problem is that simply adjusting "bytes" in NVMEM providers would result in core code NOT passing whole raw data to .read_post_process() callbacks. It means callback functions couldn't do their job without somehow manually reading original cell content on their own. This patch deals with that by registering NVMEM cells with both lengths: raw content one and post read one. It allows: 1. Core code to read whole raw cell content 2. Callbacks to return content they want Signed-off-by: Rafał Miłecki <rafal@milecki.pl> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> Link: https://lore.kernel.org/r/20230404172148.82422-35-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-04-04 17:21:42 +00:00
size_t raw_len;
unsigned int bytes;
unsigned int bit_offset;
unsigned int nbits;
struct device_node *np;
nvmem_cell_post_process_t read_post_process;
void *priv;
};
/**
* struct nvmem_config - NVMEM device configuration
*
* @dev: Parent device.
* @name: Optional name.
* @id: Optional device ID used in full name. Ignored if name is NULL.
* @owner: Pointer to exporter module. Used for refcounting.
* @cells: Optional array of pre-defined NVMEM cells.
* @ncells: Number of elements in cells.
* @keepout: Optional array of keepout ranges (sorted ascending by start).
* @nkeepout: Number of elements in the keepout array.
* @type: Type of the nvmem storage
* @read_only: Device is read-only.
* @root_only: Device is accessibly to root only.
* @of_node: If given, this will be used instead of the parent's of_node.
* @no_of_node: Device should not use the parent's of_node even if it's !NULL.
* @reg_read: Callback to read data.
* @reg_write: Callback to write data.
* @size: Device size.
* @word_size: Minimum read/write access granularity.
* @stride: Minimum read/write access stride.
* @priv: User context passed to read/write callbacks.
* @ignore_wp: Write Protect pin is managed by the provider.
* @layout: Fixed layout associated with this nvmem device.
*
* Note: A default "nvmem<id>" name will be assigned to the device if
* no name is specified in its configuration. In such case "<id>" is
* generated with ida_simple_get() and provided id field is ignored.
*
* Note: Specifying name and setting id to -1 implies a unique device
* whose name is provided as-is (kept unaltered).
*/
struct nvmem_config {
struct device *dev;
const char *name;
int id;
struct module *owner;
const struct nvmem_cell_info *cells;
int ncells;
const struct nvmem_keepout *keepout;
unsigned int nkeepout;
enum nvmem_type type;
bool read_only;
bool root_only;
bool ignore_wp;
struct nvmem_layout *layout;
struct device_node *of_node;
bool no_of_node;
nvmem_reg_read_t reg_read;
nvmem_reg_write_t reg_write;
int size;
int word_size;
int stride;
void *priv;
/* To be only used by old driver/misc/eeprom drivers */
bool compat;
struct device *base_dev;
};
/**
* struct nvmem_cell_table - NVMEM cell definitions for given provider
*
* @nvmem_name: Provider name.
* @cells: Array of cell definitions.
* @ncells: Number of cell definitions in the array.
* @node: List node.
*
* This structure together with related helper functions is provided for users
* that don't can't access the nvmem provided structure but wish to register
* cell definitions for it e.g. board files registering an EEPROM device.
*/
struct nvmem_cell_table {
const char *nvmem_name;
const struct nvmem_cell_info *cells;
size_t ncells;
struct list_head node;
};
/**
* struct nvmem_layout - NVMEM layout definitions
*
* @name: Layout name.
* @of_match_table: Open firmware match table.
* @add_cells: Will be called if a nvmem device is found which
* has this layout. The function will add layout
* specific cells with nvmem_add_one_cell().
* @fixup_cell_info: Will be called before a cell is added. Can be
* used to modify the nvmem_cell_info.
* @owner: Pointer to struct module.
* @node: List node.
*
* A nvmem device can hold a well defined structure which can just be
* evaluated during runtime. For example a TLV list, or a list of "name=val"
* pairs. A nvmem layout can parse the nvmem device and add appropriate
* cells.
*/
struct nvmem_layout {
const char *name;
const struct of_device_id *of_match_table;
int (*add_cells)(struct device *dev, struct nvmem_device *nvmem,
struct nvmem_layout *layout);
void (*fixup_cell_info)(struct nvmem_device *nvmem,
struct nvmem_layout *layout,
struct nvmem_cell_info *cell);
/* private */
struct module *owner;
struct list_head node;
};
#if IS_ENABLED(CONFIG_NVMEM)
struct nvmem_device *nvmem_register(const struct nvmem_config *cfg);
void nvmem_unregister(struct nvmem_device *nvmem);
struct nvmem_device *devm_nvmem_register(struct device *dev,
const struct nvmem_config *cfg);
void nvmem_add_cell_table(struct nvmem_cell_table *table);
void nvmem_del_cell_table(struct nvmem_cell_table *table);
int nvmem_add_one_cell(struct nvmem_device *nvmem,
const struct nvmem_cell_info *info);
int __nvmem_layout_register(struct nvmem_layout *layout, struct module *owner);
#define nvmem_layout_register(layout) \
__nvmem_layout_register(layout, THIS_MODULE)
void nvmem_layout_unregister(struct nvmem_layout *layout);
const void *nvmem_layout_get_match_data(struct nvmem_device *nvmem,
struct nvmem_layout *layout);
#else
static inline struct nvmem_device *nvmem_register(const struct nvmem_config *c)
{
return ERR_PTR(-EOPNOTSUPP);
}
static inline void nvmem_unregister(struct nvmem_device *nvmem) {}
static inline struct nvmem_device *
devm_nvmem_register(struct device *dev, const struct nvmem_config *c)
{
return nvmem_register(c);
}
static inline void nvmem_add_cell_table(struct nvmem_cell_table *table) {}
static inline void nvmem_del_cell_table(struct nvmem_cell_table *table) {}
static inline int nvmem_add_one_cell(struct nvmem_device *nvmem,
const struct nvmem_cell_info *info)
{
return -EOPNOTSUPP;
}
static inline int nvmem_layout_register(struct nvmem_layout *layout)
{
return -EOPNOTSUPP;
}
static inline void nvmem_layout_unregister(struct nvmem_layout *layout) {}
static inline const void *
nvmem_layout_get_match_data(struct nvmem_device *nvmem,
struct nvmem_layout *layout)
{
return NULL;
}
#endif /* CONFIG_NVMEM */
#define module_nvmem_layout_driver(__layout_driver) \
module_driver(__layout_driver, nvmem_layout_register, \
nvmem_layout_unregister)
#endif /* ifndef _LINUX_NVMEM_PROVIDER_H */