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

source code of linux/include/linux/nvmem-provider.h