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
 18struct nvmem_device;
 19typedef int (*nvmem_reg_read_t)(void *priv, unsigned int offset,
 20				void *val, size_t bytes);
 21typedef 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 */
 24typedef int (*nvmem_cell_post_process_t)(void *priv, const char *id, int index,
 25					 unsigned int offset, void *buf,
 26					 size_t bytes);
 27
 28enum 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 */
 46struct 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 */
 65struct 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_alloc() 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 */
111struct 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 */
154struct nvmem_layout {
155	struct device dev;
156	struct nvmem_device *nvmem;
157	int (*add_cells)(struct nvmem_layout *layout);
158};
159
160struct 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
168struct nvmem_device *nvmem_register(const struct nvmem_config *cfg);
169void nvmem_unregister(struct nvmem_device *nvmem);
170
171struct nvmem_device *devm_nvmem_register(struct device *dev,
172					 const struct nvmem_config *cfg);
173
174int nvmem_add_one_cell(struct nvmem_device *nvmem,
175		       const struct nvmem_cell_info *info);
176
177int nvmem_layout_register(struct nvmem_layout *layout);
178void nvmem_layout_unregister(struct nvmem_layout *layout);
179
180#define nvmem_layout_driver_register(drv) \
181	__nvmem_layout_driver_register(drv, THIS_MODULE)
182int __nvmem_layout_driver_register(struct nvmem_layout_driver *drv,
183				   struct module *owner);
184void 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
191static inline struct nvmem_device *nvmem_register(const struct nvmem_config *c)
192{
193	return ERR_PTR(-EOPNOTSUPP);
194}
195
196static inline void nvmem_unregister(struct nvmem_device *nvmem) {}
197
198static inline struct nvmem_device *
199devm_nvmem_register(struct device *dev, const struct nvmem_config *c)
200{
201	return nvmem_register(c);
202}
203
204static inline int nvmem_add_one_cell(struct nvmem_device *nvmem,
205				     const struct nvmem_cell_info *info)
206{
207	return -EOPNOTSUPP;
208}
209
210static inline int nvmem_layout_register(struct nvmem_layout *layout)
211{
212	return -EOPNOTSUPP;
213}
214
215static 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 */
229struct device_node *of_nvmem_layout_get_container(struct nvmem_device *nvmem);
230
231#else  /* CONFIG_NVMEM && CONFIG_OF */
232
233static 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 */