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 /* used for vendor specific post processing of cell data */ 23 typedef int (*nvmem_cell_post_process_t)(void *priv, const char *id, unsigned int offset, 24 void *buf, size_t bytes); 25 26 enum nvmem_type { 27 NVMEM_TYPE_UNKNOWN = 0, 28 NVMEM_TYPE_EEPROM, 29 NVMEM_TYPE_OTP, 30 NVMEM_TYPE_BATTERY_BACKED, 31 NVMEM_TYPE_FRAM, 32 }; 33 34 #define NVMEM_DEVID_NONE (-1) 35 #define NVMEM_DEVID_AUTO (-2) 36 37 /** 38 * struct nvmem_keepout - NVMEM register keepout range. 39 * 40 * @start: The first byte offset to avoid. 41 * @end: One beyond the last byte offset to avoid. 42 * @value: The byte to fill reads with for this region. 43 */ 44 struct nvmem_keepout { 45 unsigned int start; 46 unsigned int end; 47 unsigned char value; 48 }; 49 50 /** 51 * struct nvmem_config - NVMEM device configuration 52 * 53 * @dev: Parent device. 54 * @name: Optional name. 55 * @id: Optional device ID used in full name. Ignored if name is NULL. 56 * @owner: Pointer to exporter module. Used for refcounting. 57 * @cells: Optional array of pre-defined NVMEM cells. 58 * @ncells: Number of elements in cells. 59 * @keepout: Optional array of keepout ranges (sorted ascending by start). 60 * @nkeepout: Number of elements in the keepout array. 61 * @type: Type of the nvmem storage 62 * @read_only: Device is read-only. 63 * @root_only: Device is accessibly to root only. 64 * @of_node: If given, this will be used instead of the parent's of_node. 65 * @no_of_node: Device should not use the parent's of_node even if it's !NULL. 66 * @reg_read: Callback to read data. 67 * @reg_write: Callback to write data. 68 * @cell_post_process: Callback for vendor specific post processing of cell data 69 * @size: Device size. 70 * @word_size: Minimum read/write access granularity. 71 * @stride: Minimum read/write access stride. 72 * @priv: User context passed to read/write callbacks. 73 * @wp-gpio: Write protect pin 74 * @ignore_wp: Write Protect pin is managed by the provider. 75 * 76 * Note: A default "nvmem<id>" name will be assigned to the device if 77 * no name is specified in its configuration. In such case "<id>" is 78 * generated with ida_simple_get() and provided id field is ignored. 79 * 80 * Note: Specifying name and setting id to -1 implies a unique device 81 * whose name is provided as-is (kept unaltered). 82 */ 83 struct nvmem_config { 84 struct device *dev; 85 const char *name; 86 int id; 87 struct module *owner; 88 struct gpio_desc *wp_gpio; 89 const struct nvmem_cell_info *cells; 90 int ncells; 91 const struct nvmem_keepout *keepout; 92 unsigned int nkeepout; 93 enum nvmem_type type; 94 bool read_only; 95 bool root_only; 96 bool ignore_wp; 97 struct device_node *of_node; 98 bool no_of_node; 99 nvmem_reg_read_t reg_read; 100 nvmem_reg_write_t reg_write; 101 nvmem_cell_post_process_t cell_post_process; 102 int size; 103 int word_size; 104 int stride; 105 void *priv; 106 /* To be only used by old driver/misc/eeprom drivers */ 107 bool compat; 108 struct device *base_dev; 109 }; 110 111 /** 112 * struct nvmem_cell_table - NVMEM cell definitions for given provider 113 * 114 * @nvmem_name: Provider name. 115 * @cells: Array of cell definitions. 116 * @ncells: Number of cell definitions in the array. 117 * @node: List node. 118 * 119 * This structure together with related helper functions is provided for users 120 * that don't can't access the nvmem provided structure but wish to register 121 * cell definitions for it e.g. board files registering an EEPROM device. 122 */ 123 struct nvmem_cell_table { 124 const char *nvmem_name; 125 const struct nvmem_cell_info *cells; 126 size_t ncells; 127 struct list_head node; 128 }; 129 130 #if IS_ENABLED(CONFIG_NVMEM) 131 132 struct nvmem_device *nvmem_register(const struct nvmem_config *cfg); 133 void nvmem_unregister(struct nvmem_device *nvmem); 134 135 struct nvmem_device *devm_nvmem_register(struct device *dev, 136 const struct nvmem_config *cfg); 137 138 void nvmem_add_cell_table(struct nvmem_cell_table *table); 139 void nvmem_del_cell_table(struct nvmem_cell_table *table); 140 141 #else 142 143 static inline struct nvmem_device *nvmem_register(const struct nvmem_config *c) 144 { 145 return ERR_PTR(-EOPNOTSUPP); 146 } 147 148 static inline void nvmem_unregister(struct nvmem_device *nvmem) {} 149 150 static inline struct nvmem_device * 151 devm_nvmem_register(struct device *dev, const struct nvmem_config *c) 152 { 153 return nvmem_register(c); 154 } 155 156 static inline void nvmem_add_cell_table(struct nvmem_cell_table *table) {} 157 static inline void nvmem_del_cell_table(struct nvmem_cell_table *table) {} 158 159 #endif /* CONFIG_NVMEM */ 160 #endif /* ifndef _LINUX_NVMEM_PROVIDER_H */ 161