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         NVMEM_TYPE_FRAM,
  29 };
  30
  31 #define NVMEM_DEVID_NONE        (-1)
  32 #define NVMEM_DEVID_AUTO        (-2)
  33
  34 /**
  35  * struct nvmem_keepout - NVMEM register keepout range.
  36  *
  37  * @start:      The first byte offset to avoid.
  38  * @end:        One beyond the last byte offset to avoid.
  39  * @value:      The byte to fill reads with for this region.
  40  */
  41 struct nvmem_keepout {
  42         unsigned int start;
  43         unsigned int end;
  44         unsigned char value;
  45 };
  46
  47 /**
  48  * struct nvmem_config - NVMEM device configuration
  49  *
  50  * @dev:        Parent device.
  51  * @name:       Optional name.
  52  * @id:         Optional device ID used in full name. Ignored if name is NULL.
  53  * @owner:      Pointer to exporter module. Used for refcounting.
  54  * @cells:      Optional array of pre-defined NVMEM cells.
  55  * @ncells:     Number of elements in cells.
  56  * @keepout:    Optional array of keepout ranges (sorted ascending by start).
  57  * @nkeepout:   Number of elements in the keepout array.
  58  * @type:       Type of the nvmem storage
  59  * @read_only:  Device is read-only.
  60  * @root_only:  Device is accessibly to root only.
  61  * @of_node:    If given, this will be used instead of the parent's of_node.
  62  * @no_of_node: Device should not use the parent's of_node even if it's !NULL.
  63  * @reg_read:   Callback to read data.
  64  * @reg_write:  Callback to write data.
  65  * @size:       Device size.
  66  * @word_size:  Minimum read/write access granularity.
  67  * @stride:     Minimum read/write access stride.
  68  * @priv:       User context passed to read/write callbacks.
  69  * @wp-gpio:   Write protect pin
  70  *
  71  * Note: A default "nvmem<id>" name will be assigned to the device if
  72  * no name is specified in its configuration. In such case "<id>" is
  73  * generated with ida_simple_get() and provided id field is ignored.
  74  *
  75  * Note: Specifying name and setting id to -1 implies a unique device
  76  * whose name is provided as-is (kept unaltered).
  77  */
  78 struct nvmem_config {
  79         struct device           *dev;
  80         const char              *name;
  81         int                     id;
  82         struct module           *owner;
  83         struct gpio_desc        *wp_gpio;
  84         const struct nvmem_cell_info    *cells;
  85         int                     ncells;
  86         const struct nvmem_keepout *keepout;
  87         unsigned int            nkeepout;
  88         enum nvmem_type         type;
  89         bool                    read_only;
  90         bool                    root_only;
  91         struct device_node      *of_node;
  92         bool                    no_of_node;
  93         nvmem_reg_read_t        reg_read;
  94         nvmem_reg_write_t       reg_write;
  95         int     size;
  96         int     word_size;
  97         int     stride;
  98         void    *priv;
  99         /* To be only used by old driver/misc/eeprom drivers */
 100         bool                    compat;
 101         struct device           *base_dev;
 102 };
 103
 104 /**
 105  * struct nvmem_cell_table - NVMEM cell definitions for given provider
 106  *
 107  * @nvmem_name:         Provider name.
 108  * @cells:              Array of cell definitions.
 109  * @ncells:             Number of cell definitions in the array.
 110  * @node:               List node.
 111  *
 112  * This structure together with related helper functions is provided for users
 113  * that don't can't access the nvmem provided structure but wish to register
 114  * cell definitions for it e.g. board files registering an EEPROM device.
 115  */
 116 struct nvmem_cell_table {
 117         const char              *nvmem_name;
 118         const struct nvmem_cell_info    *cells;
 119         size_t                  ncells;
 120         struct list_head        node;
 121 };
 122
 123 #if IS_ENABLED(CONFIG_NVMEM)
 124
 125 struct nvmem_device *nvmem_register(const struct nvmem_config *cfg);
 126 void nvmem_unregister(struct nvmem_device *nvmem);
 127
 128 struct nvmem_device *devm_nvmem_register(struct device *dev,
 129                                          const struct nvmem_config *cfg);
 130
 131 int devm_nvmem_unregister(struct device *dev, struct nvmem_device *nvmem);
 132
 133 void nvmem_add_cell_table(struct nvmem_cell_table *table);
 134 void nvmem_del_cell_table(struct nvmem_cell_table *table);
 135
 136 #else
 137
 138 static inline struct nvmem_device *nvmem_register(const struct nvmem_config *c)
 139 {
 140         return ERR_PTR(-EOPNOTSUPP);
 141 }
 142
 143 static inline void nvmem_unregister(struct nvmem_device *nvmem) {}
 144
 145 static inline struct nvmem_device *
 146 devm_nvmem_register(struct device *dev, const struct nvmem_config *c)
 147 {
 148         return nvmem_register(c);
 149 }
 150
 151 static inline int
 152 devm_nvmem_unregister(struct device *dev, struct nvmem_device *nvmem)
 153 {
 154         return -EOPNOTSUPP;
 155 }
 156
 157 static inline void nvmem_add_cell_table(struct nvmem_cell_table *table) {}
 158 static inline void nvmem_del_cell_table(struct nvmem_cell_table *table) {}
 159
 160 #endif /* CONFIG_NVMEM */
 161 #endif  /* ifndef _LINUX_NVMEM_PROVIDER_H */