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