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; return zero if successful.
96 * @reg_write: Callback to write data; return zero if successful.
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_layout - NVMEM layout definitions
142 *
143 * @dev: Device-model layout device.
144 * @nvmem: The underlying NVMEM device
145 * @add_cells: Will be called if a nvmem device is found which
146 * has this layout. The function will add layout
147 * specific cells with nvmem_add_one_cell().
148 *
149 * A nvmem device can hold a well defined structure which can just be
150 * evaluated during runtime. For example a TLV list, or a list of "name=val"
151 * pairs. A nvmem layout can parse the nvmem device and add appropriate
152 * cells.
153 */
154 struct nvmem_layout {
155 struct device dev;
156 struct nvmem_device *nvmem;
157 int (*add_cells)(struct nvmem_layout *layout);
158 };
159
160 struct nvmem_layout_driver {
161 struct device_driver driver;
162 int (*probe)(struct nvmem_layout *layout);
163 void (*remove)(struct nvmem_layout *layout);
164 };
165
166 #if IS_ENABLED(CONFIG_NVMEM)
167
168 struct nvmem_device *nvmem_register(const struct nvmem_config *cfg);
169 void nvmem_unregister(struct nvmem_device *nvmem);
170
171 struct nvmem_device *devm_nvmem_register(struct device *dev,
172 const struct nvmem_config *cfg);
173
174 int nvmem_add_one_cell(struct nvmem_device *nvmem,
175 const struct nvmem_cell_info *info);
176
177 int nvmem_layout_register(struct nvmem_layout *layout);
178 void nvmem_layout_unregister(struct nvmem_layout *layout);
179
180 #define nvmem_layout_driver_register(drv) \
181 __nvmem_layout_driver_register(drv, THIS_MODULE)
182 int __nvmem_layout_driver_register(struct nvmem_layout_driver *drv,
183 struct module *owner);
184 void nvmem_layout_driver_unregister(struct nvmem_layout_driver *drv);
185 #define module_nvmem_layout_driver(__nvmem_layout_driver) \
186 module_driver(__nvmem_layout_driver, nvmem_layout_driver_register, \
187 nvmem_layout_driver_unregister)
188
189 #else
190
nvmem_register(const struct nvmem_config * c)191 static inline struct nvmem_device *nvmem_register(const struct nvmem_config *c)
192 {
193 return ERR_PTR(-EOPNOTSUPP);
194 }
195
nvmem_unregister(struct nvmem_device * nvmem)196 static inline void nvmem_unregister(struct nvmem_device *nvmem) {}
197
198 static inline struct nvmem_device *
devm_nvmem_register(struct device * dev,const struct nvmem_config * c)199 devm_nvmem_register(struct device *dev, const struct nvmem_config *c)
200 {
201 return nvmem_register(c);
202 }
203
nvmem_add_one_cell(struct nvmem_device * nvmem,const struct nvmem_cell_info * info)204 static inline int nvmem_add_one_cell(struct nvmem_device *nvmem,
205 const struct nvmem_cell_info *info)
206 {
207 return -EOPNOTSUPP;
208 }
209
nvmem_layout_register(struct nvmem_layout * layout)210 static inline int nvmem_layout_register(struct nvmem_layout *layout)
211 {
212 return -EOPNOTSUPP;
213 }
214
nvmem_layout_unregister(struct nvmem_layout * layout)215 static inline void nvmem_layout_unregister(struct nvmem_layout *layout) {}
216
217 #endif /* CONFIG_NVMEM */
218
219 #if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF)
220
221 /**
222 * of_nvmem_layout_get_container() - Get OF node of layout container
223 *
224 * @nvmem: nvmem device
225 *
226 * Return: a node pointer with refcount incremented or NULL if no
227 * container exists. Use of_node_put() on it when done.
228 */
229 struct device_node *of_nvmem_layout_get_container(struct nvmem_device *nvmem);
230
231 #else /* CONFIG_NVMEM && CONFIG_OF */
232
of_nvmem_layout_get_container(struct nvmem_device * nvmem)233 static inline struct device_node *of_nvmem_layout_get_container(struct nvmem_device *nvmem)
234 {
235 return NULL;
236 }
237
238 #endif /* CONFIG_NVMEM && CONFIG_OF */
239
240 #endif /* ifndef _LINUX_NVMEM_PROVIDER_H */
241