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