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