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
nvmem_register(const struct nvmem_config * c)138 static inline struct nvmem_device *nvmem_register(const struct nvmem_config *c)
139 {
140 return ERR_PTR(-EOPNOTSUPP);
141 }
142
nvmem_unregister(struct nvmem_device * nvmem)143 static inline void nvmem_unregister(struct nvmem_device *nvmem) {}
144
145 static inline struct nvmem_device *
devm_nvmem_register(struct device * dev,const struct nvmem_config * c)146 devm_nvmem_register(struct device *dev, const struct nvmem_config *c)
147 {
148 return nvmem_register(c);
149 }
150
151 static inline int
devm_nvmem_unregister(struct device * dev,struct nvmem_device * nvmem)152 devm_nvmem_unregister(struct device *dev, struct nvmem_device *nvmem)
153 {
154 return -EOPNOTSUPP;
155 }
156
nvmem_add_cell_table(struct nvmem_cell_table * table)157 static inline void nvmem_add_cell_table(struct nvmem_cell_table *table) {}
nvmem_del_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 */
162
