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_keepout - NVMEM register keepout range.
  35 *
  36 * @start:      The first byte offset to avoid.
  37 * @end:        One beyond the last byte offset to avoid.
  38 * @value:      The byte to fill reads with for this region.
  39 */
  40struct nvmem_keepout {
  41        unsigned int start;
  42        unsigned int end;
  43        unsigned char value;
  44};
  45
  46/**
  47 * struct nvmem_config - NVMEM device configuration
  48 *
  49 * @dev:        Parent device.
  50 * @name:       Optional name.
  51 * @id:         Optional device ID used in full name. Ignored if name is NULL.
  52 * @owner:      Pointer to exporter module. Used for refcounting.
  53 * @cells:      Optional array of pre-defined NVMEM cells.
  54 * @ncells:     Number of elements in cells.
  55 * @keepout:    Optional array of keepout ranges (sorted ascending by start).
  56 * @nkeepout:   Number of elements in the keepout array.
  57 * @type:       Type of the nvmem storage
  58 * @read_only:  Device is read-only.
  59 * @root_only:  Device is accessibly to root only.
  60 * @no_of_node: Device should not use the parent's of_node even if it's !NULL.
  61 * @reg_read:   Callback to read data.
  62 * @reg_write:  Callback to write data.
  63 * @size:       Device size.
  64 * @word_size:  Minimum read/write access granularity.
  65 * @stride:     Minimum read/write access stride.
  66 * @priv:       User context passed to read/write callbacks.
  67 * @wp-gpio:   Write protect pin
  68 *
  69 * Note: A default "nvmem<id>" name will be assigned to the device if
  70 * no name is specified in its configuration. In such case "<id>" is
  71 * generated with ida_simple_get() and provided id field is ignored.
  72 *
  73 * Note: Specifying name and setting id to -1 implies a unique device
  74 * whose name is provided as-is (kept unaltered).
  75 */
  76struct nvmem_config {
  77        struct device           *dev;
  78        const char              *name;
  79        int                     id;
  80        struct module           *owner;
  81        struct gpio_desc        *wp_gpio;
  82        const struct nvmem_cell_info    *cells;
  83        int                     ncells;
  84        const struct nvmem_keepout *keepout;
  85        unsigned int            nkeepout;
  86        enum nvmem_type         type;
  87        bool                    read_only;
  88        bool                    root_only;
  89        bool                    no_of_node;
  90        nvmem_reg_read_t        reg_read;
  91        nvmem_reg_write_t       reg_write;
  92        int     size;
  93        int     word_size;
  94        int     stride;
  95        void    *priv;
  96        /* To be only used by old driver/misc/eeprom drivers */
  97        bool                    compat;
  98        struct device           *base_dev;
  99};
 100
 101/**
 102 * struct nvmem_cell_table - NVMEM cell definitions for given provider
 103 *
 104 * @nvmem_name:         Provider name.
 105 * @cells:              Array of cell definitions.
 106 * @ncells:             Number of cell definitions in the array.
 107 * @node:               List node.
 108 *
 109 * This structure together with related helper functions is provided for users
 110 * that don't can't access the nvmem provided structure but wish to register
 111 * cell definitions for it e.g. board files registering an EEPROM device.
 112 */
 113struct nvmem_cell_table {
 114        const char              *nvmem_name;
 115        const struct nvmem_cell_info    *cells;
 116        size_t                  ncells;
 117        struct list_head        node;
 118};
 119
 120#if IS_ENABLED(CONFIG_NVMEM)
 121
 122struct nvmem_device *nvmem_register(const struct nvmem_config *cfg);
 123void nvmem_unregister(struct nvmem_device *nvmem);
 124
 125struct nvmem_device *devm_nvmem_register(struct device *dev,
 126                                         const struct nvmem_config *cfg);
 127
 128int devm_nvmem_unregister(struct device *dev, struct nvmem_device *nvmem);
 129
 130void nvmem_add_cell_table(struct nvmem_cell_table *table);
 131void nvmem_del_cell_table(struct nvmem_cell_table *table);
 132
 133#else
 134
 135static inline struct nvmem_device *nvmem_register(const struct nvmem_config *c)
 136{
 137        return ERR_PTR(-EOPNOTSUPP);
 138}
 139
 140static inline void nvmem_unregister(struct nvmem_device *nvmem) {}
 141
 142static inline struct nvmem_device *
 143devm_nvmem_register(struct device *dev, const struct nvmem_config *c)
 144{
 145        return nvmem_register(c);
 146}
 147
 148static inline int
 149devm_nvmem_unregister(struct device *dev, struct nvmem_device *nvmem)
 150{
 151        return -EOPNOTSUPP;
 152}
 153
 154static inline void nvmem_add_cell_table(struct nvmem_cell_table *table) {}
 155static inline void nvmem_del_cell_table(struct nvmem_cell_table *table) {}
 156
 157#endif /* CONFIG_NVMEM */
 158#endif  /* ifndef _LINUX_NVMEM_PROVIDER_H */
 159