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/device.h>
  13 #include <linux/device/driver.h>
  14 #include <linux/err.h>
  15 #include <linux/errno.h>
  16 #include <linux/gpio/consumer.h>
  17
  18 struct nvmem_device;
  19 typedef int (*nvmem_reg_read_t)(void *priv, unsigned int offset,
  20                                 void *val, size_t bytes);
  21 typedef int (*nvmem_reg_write_t)(void *priv, unsigned int offset,
  22                                  void *val, size_t bytes);
  23 /* used for vendor specific post processing of cell data */
  24 typedef int (*nvmem_cell_post_process_t)(void *priv, const char *id, int index,
  25                                          unsigned int offset, void *buf,
  26                                          size_t bytes);
  27
  28 enum nvmem_type {
  29         NVMEM_TYPE_UNKNOWN = 0,
  30         NVMEM_TYPE_EEPROM,
  31         NVMEM_TYPE_OTP,
  32         NVMEM_TYPE_BATTERY_BACKED,
  33         NVMEM_TYPE_FRAM,
  34 };
  35
  36 #define NVMEM_DEVID_NONE        (-1)
  37 #define NVMEM_DEVID_AUTO        (-2)
  38
  39 /**
  40  * struct nvmem_keepout - NVMEM register keepout range.
  41  *
  42  * @start:      The first byte offset to avoid.
  43  * @end:        One beyond the last byte offset to avoid.
  44  * @value:      The byte to fill reads with for this region.
  45  */
  46 struct nvmem_keepout {
  47         unsigned int start;
  48         unsigned int end;
  49         unsigned char value;
  50 };
  51
  52 /**
  53  * struct nvmem_cell_info - NVMEM cell description
  54  * @name:       Name.
  55  * @offset:     Offset within the NVMEM device.
  56  * @raw_len:    Length of raw data (without post processing).
  57  * @bytes:      Length of the cell.
  58  * @bit_offset: Bit offset if cell is smaller than a byte.
  59  * @nbits:      Number of bits.
  60  * @np:         Optional device_node pointer.
  61  * @read_post_process:  Callback for optional post processing of cell data
  62  *                      on reads.
  63  * @priv:       Opaque data passed to the read_post_process hook.
  64  */
  65 struct nvmem_cell_info {
  66         const char              *name;
  67         unsigned int            offset;
  68         size_t                  raw_len;
  69         unsigned int            bytes;
  70         unsigned int            bit_offset;
  71         unsigned int            nbits;
  72         struct device_node      *np;
  73         nvmem_cell_post_process_t read_post_process;
  74         void                    *priv;
  75 };
  76
  77 /**
  78  * struct nvmem_config - NVMEM device configuration
  79  *
  80  * @dev:        Parent device.
  81  * @name:       Optional name.
  82  * @id:         Optional device ID used in full name. Ignored if name is NULL.
  83  * @owner:      Pointer to exporter module. Used for refcounting.
  84  * @cells:      Optional array of pre-defined NVMEM cells.
  85  * @ncells:     Number of elements in cells.
  86  * @add_legacy_fixed_of_cells:  Read fixed NVMEM cells from old OF syntax.
  87  * @fixup_dt_cell_info: Will be called before a cell is added. Can be
  88  *              used to modify the nvmem_cell_info.
  89  * @keepout:    Optional array of keepout ranges (sorted ascending by start).
  90  * @nkeepout:   Number of elements in the keepout array.
  91  * @type:       Type of the nvmem storage
  92  * @read_only:  Device is read-only.
  93  * @root_only:  Device is accessibly to root only.
  94  * @of_node:    If given, this will be used instead of the parent's of_node.
  95  * @reg_read:   Callback to read data.
  96  * @reg_write:  Callback to write data.
  97  * @size:       Device size.
  98  * @word_size:  Minimum read/write access granularity.
  99  * @stride:     Minimum read/write access stride.
 100  * @priv:       User context passed to read/write callbacks.
 101  * @ignore_wp:  Write Protect pin is managed by the provider.
 102  * @layout:     Fixed layout associated with this nvmem device.
 103  *
 104  * Note: A default "nvmem<id>" name will be assigned to the device if
 105  * no name is specified in its configuration. In such case "<id>" is
 106  * generated with ida_simple_get() and provided id field is ignored.
 107  *
 108  * Note: Specifying name and setting id to -1 implies a unique device
 109  * whose name is provided as-is (kept unaltered).
 110  */
 111 struct nvmem_config {
 112         struct device           *dev;
 113         const char              *name;
 114         int                     id;
 115         struct module           *owner;
 116         const struct nvmem_cell_info    *cells;
 117         int                     ncells;
 118         bool                    add_legacy_fixed_of_cells;
 119         void (*fixup_dt_cell_info)(struct nvmem_device *nvmem,
 120                                    struct nvmem_cell_info *cell);
 121         const struct nvmem_keepout *keepout;
 122         unsigned int            nkeepout;
 123         enum nvmem_type         type;
 124         bool                    read_only;
 125         bool                    root_only;
 126         bool                    ignore_wp;
 127         struct nvmem_layout     *layout;
 128         struct device_node      *of_node;
 129         nvmem_reg_read_t        reg_read;
 130         nvmem_reg_write_t       reg_write;
 131         int     size;
 132         int     word_size;
 133         int     stride;
 134         void    *priv;
 135         /* To be only used by old driver/misc/eeprom drivers */
 136         bool                    compat;
 137         struct device           *base_dev;
 138 };
 139
 140 /**
 141  * struct nvmem_cell_table - NVMEM cell definitions for given provider
 142  *
 143  * @nvmem_name:         Provider name.
 144  * @cells:              Array of cell definitions.
 145  * @ncells:             Number of cell definitions in the array.
 146  * @node:               List node.
 147  *
 148  * This structure together with related helper functions is provided for users
 149  * that don't can't access the nvmem provided structure but wish to register
 150  * cell definitions for it e.g. board files registering an EEPROM device.
 151  */
 152 struct nvmem_cell_table {
 153         const char              *nvmem_name;
 154         const struct nvmem_cell_info    *cells;
 155         size_t                  ncells;
 156         struct list_head        node;
 157 };
 158
 159 /**
 160  * struct nvmem_layout - NVMEM layout definitions
 161  *
 162  * @dev:                Device-model layout device.
 163  * @nvmem:              The underlying NVMEM device
 164  * @add_cells:          Will be called if a nvmem device is found which
 165  *                      has this layout. The function will add layout
 166  *                      specific cells with nvmem_add_one_cell().
 167  *
 168  * A nvmem device can hold a well defined structure which can just be
 169  * evaluated during runtime. For example a TLV list, or a list of "name=val"
 170  * pairs. A nvmem layout can parse the nvmem device and add appropriate
 171  * cells.
 172  */
 173 struct nvmem_layout {
 174         struct device dev;
 175         struct nvmem_device *nvmem;
 176         int (*add_cells)(struct nvmem_layout *layout);
 177 };
 178
 179 struct nvmem_layout_driver {
 180         struct device_driver driver;
 181         int (*probe)(struct nvmem_layout *layout);
 182         void (*remove)(struct nvmem_layout *layout);
 183 };
 184
 185 #if IS_ENABLED(CONFIG_NVMEM)
 186
 187 struct nvmem_device *nvmem_register(const struct nvmem_config *cfg);
 188 void nvmem_unregister(struct nvmem_device *nvmem);
 189
 190 struct nvmem_device *devm_nvmem_register(struct device *dev,
 191                                          const struct nvmem_config *cfg);
 192
 193 void nvmem_add_cell_table(struct nvmem_cell_table *table);
 194 void nvmem_del_cell_table(struct nvmem_cell_table *table);
 195
 196 int nvmem_add_one_cell(struct nvmem_device *nvmem,
 197                        const struct nvmem_cell_info *info);
 198
 199 int nvmem_layout_register(struct nvmem_layout *layout);
 200 void nvmem_layout_unregister(struct nvmem_layout *layout);
 201
 202 #define nvmem_layout_driver_register(drv) \
 203         __nvmem_layout_driver_register(drv, THIS_MODULE)
 204 int __nvmem_layout_driver_register(struct nvmem_layout_driver *drv,
 205                                    struct module *owner);
 206 void nvmem_layout_driver_unregister(struct nvmem_layout_driver *drv);
 207 #define module_nvmem_layout_driver(__nvmem_layout_driver)               \
 208         module_driver(__nvmem_layout_driver, nvmem_layout_driver_register, \
 209                       nvmem_layout_driver_unregister)
 210
 211 #else
 212
 213 static inline struct nvmem_device *nvmem_register(const struct nvmem_config *c)
 214 {
 215         return ERR_PTR(-EOPNOTSUPP);
 216 }
 217
 218 static inline void nvmem_unregister(struct nvmem_device *nvmem) {}
 219
 220 static inline struct nvmem_device *
 221 devm_nvmem_register(struct device *dev, const struct nvmem_config *c)
 222 {
 223         return nvmem_register(c);
 224 }
 225
 226 static inline void nvmem_add_cell_table(struct nvmem_cell_table *table) {}
 227 static inline void nvmem_del_cell_table(struct nvmem_cell_table *table) {}
 228 static inline int nvmem_add_one_cell(struct nvmem_device *nvmem,
 229                                      const struct nvmem_cell_info *info)
 230 {
 231         return -EOPNOTSUPP;
 232 }
 233
 234 static inline int nvmem_layout_register(struct nvmem_layout *layout)
 235 {
 236         return -EOPNOTSUPP;
 237 }
 238
 239 static inline void nvmem_layout_unregister(struct nvmem_layout *layout) {}
 240
 241 #endif /* CONFIG_NVMEM */
 242
 243 #if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF)
 244
 245 /**
 246  * of_nvmem_layout_get_container() - Get OF node of layout container
 247  *
 248  * @nvmem: nvmem device
 249  *
 250  * Return: a node pointer with refcount incremented or NULL if no
 251  * container exists. Use of_node_put() on it when done.
 252  */
 253 struct device_node *of_nvmem_layout_get_container(struct nvmem_device *nvmem);
 254
 255 #else  /* CONFIG_NVMEM && CONFIG_OF */
 256
 257 static inline struct device_node *of_nvmem_layout_get_container(struct nvmem_device *nvmem)
 258 {
 259         return NULL;
 260 }
 261
 262 #endif /* CONFIG_NVMEM && CONFIG_OF */
 263
 264 #endif  /* ifndef _LINUX_NVMEM_PROVIDER_H */