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

   1/* SPDX-License-Identifier: GPL-2.0 */
   2/*
   3 * nvmem framework provider.
   4 *
   5 * Copyright (C) 2015 Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
   6 * Copyright (C) 2013 Maxime Ripard <maxime.ripard@free-electrons.com>
   7 */
   8
   9#ifndef _LINUX_NVMEM_PROVIDER_H
  10#define _LINUX_NVMEM_PROVIDER_H
  11
  12#include <linux/err.h>
  13#include <linux/errno.h>
  14#include <linux/gpio/consumer.h>
  15
  16struct nvmem_device;
  17struct nvmem_cell_info;
  18typedef int (*nvmem_reg_read_t)(void *priv, unsigned int offset,
  19                                void *val, size_t bytes);
  20typedef int (*nvmem_reg_write_t)(void *priv, unsigned int offset,
  21                                 void *val, size_t bytes);
  22
  23enum nvmem_type {
  24        NVMEM_TYPE_UNKNOWN = 0,
  25        NVMEM_TYPE_EEPROM,
  26        NVMEM_TYPE_OTP,
  27        NVMEM_TYPE_BATTERY_BACKED,
  28};
  29
  30#define NVMEM_DEVID_NONE        (-1)
  31#define NVMEM_DEVID_AUTO        (-2)
  32
  33/**
  34 * struct nvmem_config - NVMEM device configuration
  35 *
  36 * @dev:        Parent device.
  37 * @name:       Optional name.
  38 * @id:         Optional device ID used in full name. Ignored if name is NULL.
  39 * @owner:      Pointer to exporter module. Used for refcounting.
  40 * @cells:      Optional array of pre-defined NVMEM cells.
  41 * @ncells:     Number of elements in cells.
  42 * @type:       Type of the nvmem storage
  43 * @read_only:  Device is read-only.
  44 * @root_only:  Device is accessibly to root only.
  45 * @no_of_node: Device should not use the parent's of_node even if it's !NULL.
  46 * @reg_read:   Callback to read data.
  47 * @reg_write:  Callback to write data.
  48 * @size:       Device size.
  49 * @word_size:  Minimum read/write access granularity.
  50 * @stride:     Minimum read/write access stride.
  51 * @priv:       User context passed to read/write callbacks.
  52 * @wp-gpio:   Write protect pin
  53 *
  54 * Note: A default "nvmem<id>" name will be assigned to the device if
  55 * no name is specified in its configuration. In such case "<id>" is
  56 * generated with ida_simple_get() and provided id field is ignored.
  57 *
  58 * Note: Specifying name and setting id to -1 implies a unique device
  59 * whose name is provided as-is (kept unaltered).
  60 */
  61struct nvmem_config {
  62        struct device           *dev;
  63        const char              *name;
  64        int                     id;
  65        struct module           *owner;
  66        struct gpio_desc        *wp_gpio;
  67        const struct nvmem_cell_info    *cells;
  68        int                     ncells;
  69        enum nvmem_type         type;
  70        bool                    read_only;
  71        bool                    root_only;
  72        bool                    no_of_node;
  73        nvmem_reg_read_t        reg_read;
  74        nvmem_reg_write_t       reg_write;
  75        int     size;
  76        int     word_size;
  77        int     stride;
  78        void    *priv;
  79        /* To be only used by old driver/misc/eeprom drivers */
  80        bool                    compat;
  81        struct device           *base_dev;
  82};
  83
  84/**
  85 * struct nvmem_cell_table - NVMEM cell definitions for given provider
  86 *
  87 * @nvmem_name:         Provider name.
  88 * @cells:              Array of cell definitions.
  89 * @ncells:             Number of cell definitions in the array.
  90 * @node:               List node.
  91 *
  92 * This structure together with related helper functions is provided for users
  93 * that don't can't access the nvmem provided structure but wish to register
  94 * cell definitions for it e.g. board files registering an EEPROM device.
  95 */
  96struct nvmem_cell_table {
  97        const char              *nvmem_name;
  98        const struct nvmem_cell_info    *cells;
  99        size_t                  ncells;
 100        struct list_head        node;
 101};
 102
 103#if IS_ENABLED(CONFIG_NVMEM)
 104
 105struct nvmem_device *nvmem_register(const struct nvmem_config *cfg);
 106void nvmem_unregister(struct nvmem_device *nvmem);
 107
 108struct nvmem_device *devm_nvmem_register(struct device *dev,
 109                                         const struct nvmem_config *cfg);
 110
 111int devm_nvmem_unregister(struct device *dev, struct nvmem_device *nvmem);
 112
 113void nvmem_add_cell_table(struct nvmem_cell_table *table);
 114void nvmem_del_cell_table(struct nvmem_cell_table *table);
 115
 116#else
 117
 118static inline struct nvmem_device *nvmem_register(const struct nvmem_config *c)
 119{
 120        return ERR_PTR(-EOPNOTSUPP);
 121}
 122
 123static inline void nvmem_unregister(struct nvmem_device *nvmem) {}
 124
 125static inline struct nvmem_device *
 126devm_nvmem_register(struct device *dev, const struct nvmem_config *c)
 127{
 128        return nvmem_register(c);
 129}
 130
 131static inline int
 132devm_nvmem_unregister(struct device *dev, struct nvmem_device *nvmem)
 133{
 134        return -EOPNOTSUPP;
 135}
 136
 137static inline void nvmem_add_cell_table(struct nvmem_cell_table *table) {}
 138static inline void nvmem_del_cell_table(struct nvmem_cell_table *table) {}
 139
 140#endif /* CONFIG_NVMEM */
 141#endif  /* ifndef _LINUX_NVMEM_PROVIDER_H */
 142