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	These headers follow the pattern:
| #if CONFIG_IS_ENABLED(FANCY_FEATURE)
|   void foo(void);
| #else
|   static inline void foo(void) { return -ENOSYS; }
| #endif
In the #else path ENOSYS is used, however linux/errno.h is not included.
If errno.h has not been included already the compiler errors out even
if the inline function is not referenced.
Make those headers self contained.
Signed-off-by: Max Krummenacher <max.krummenacher@toradex.com>
Reviewed-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
		
	
			
		
			
				
	
	
		
			137 lines
		
	
	
		
			3.9 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			137 lines
		
	
	
		
			3.9 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /* SPDX-License-Identifier: GPL-2.0+ */
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| /*
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|  * Copyright (c) 2022 Sean Anderson <sean.anderson@seco.com>
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|  */
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| 
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| #ifndef NVMEM_H
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| #define NVMEM_H
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| 
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| #include <linux/errno.h>
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| 
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| /**
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|  * DOC: Design
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|  *
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|  * The NVMEM subsystem is a "meta-uclass" in that it abstracts over several
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|  * different uclasses all with read/write APIs. One approach to implementing
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|  * this could be to add a new sub-device for each nvmem-style device of
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|  * UCLASS_NVMEM. This subsystem has taken the approach of using the existing
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|  * access methods (i2c_eeprom_write, misc_write, etc.) directly. This has the
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|  * advantage of not requiring an extra device/driver, saving on binary size and
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|  * runtime memory usage. On the other hand, it is not idiomatic. Similar
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|  * efforts should generally use a new uclass.
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|  */
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| 
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| /**
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|  * struct nvmem_cell - One datum within non-volatile memory
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|  * @nvmem: The backing storage device
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|  * @offset: The offset of the cell from the start of @nvmem
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|  * @size: The size of the cell, in bytes
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|  */
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| struct nvmem_cell {
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| 	struct udevice *nvmem;
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| 	unsigned int offset;
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| 	size_t size;
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| };
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| 
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| struct udevice;
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| 
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| #if CONFIG_IS_ENABLED(NVMEM)
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| 
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| /**
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|  * nvmem_cell_read() - Read the value of an nvmem cell
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|  * @cell: The nvmem cell to read
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|  * @buf: The buffer to read into
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|  * @size: The size of @buf
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|  *
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|  * Return:
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|  * * 0 on success
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|  * * -EINVAL if @buf is not the same size as @cell.
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|  * * -ENOSYS if CONFIG_NVMEM is disabled
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|  * * A negative error if there was a problem reading the underlying storage
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|  */
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| int nvmem_cell_read(struct nvmem_cell *cell, void *buf, size_t size);
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| 
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| /**
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|  * nvmem_cell_write() - Write a value to an nvmem cell
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|  * @cell: The nvmem cell to write
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|  * @buf: The buffer to write from
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|  * @size: The size of @buf
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|  *
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|  * Return:
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|  * * 0 on success
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|  * * -EINVAL if @buf is not the same size as @cell
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|  * * -ENOSYS if @cell is read-only, or if CONFIG_NVMEM is disabled
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|  * * A negative error if there was a problem writing the underlying storage
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|  */
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| int nvmem_cell_write(struct nvmem_cell *cell, const void *buf, size_t size);
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| 
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| /**
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|  * nvmem_cell_get_by_index() - Get an nvmem cell from a given device and index
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|  * @dev: The device that uses the nvmem cell
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|  * @index: The index of the cell in nvmem-cells
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|  * @cell: The cell to initialize
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|  *
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|  * Look up the nvmem cell referenced by the phandle at @index in nvmem-cells in
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|  * @dev.
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|  *
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|  * Return:
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|  * * 0 on success
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|  * * -EINVAL if the regs property is missing, empty, or undersized
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|  * * -ENODEV if the nvmem device is missing or unimplemented
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|  * * -ENOSYS if CONFIG_NVMEM is disabled
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|  * * A negative error if there was a problem reading nvmem-cells or getting the
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|  *   device
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|  */
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| int nvmem_cell_get_by_index(struct udevice *dev, int index,
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| 			    struct nvmem_cell *cell);
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| 
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| /**
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|  * nvmem_cell_get_by_name() - Get an nvmem cell from a given device and name
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|  * @dev: The device that uses the nvmem cell
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|  * @name: The name of the nvmem cell
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|  * @cell: The cell to initialize
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|  *
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|  * Look up the nvmem cell referenced by @name in the nvmem-cell-names property
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|  * of @dev.
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|  *
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|  * Return:
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|  * * 0 on success
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|  * * -EINVAL if the regs property is missing, empty, or undersized
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|  * * -ENODEV if the nvmem device is missing or unimplemented
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|  * * -ENODATA if @name is not in nvmem-cell-names
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|  * * -ENOSYS if CONFIG_NVMEM is disabled
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|  * * A negative error if there was a problem reading nvmem-cell-names,
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|  *   nvmem-cells, or getting the device
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|  */
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| int nvmem_cell_get_by_name(struct udevice *dev, const char *name,
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| 			   struct nvmem_cell *cell);
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| 
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| #else /* CONFIG_NVMEM */
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| 
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| static inline int nvmem_cell_read(struct nvmem_cell *cell, void *buf, int size)
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| {
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| 	return -ENOSYS;
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| }
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| 
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| static inline int nvmem_cell_write(struct nvmem_cell *cell, const void *buf,
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| 				   int size)
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| {
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| 	return -ENOSYS;
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| }
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| 
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| static inline int nvmem_cell_get_by_index(struct udevice *dev, int index,
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| 					  struct nvmem_cell *cell)
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| {
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| 	return -ENOSYS;
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| }
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| 
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| static inline int nvmem_cell_get_by_name(struct udevice *dev, const char *name,
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| 					 struct nvmem_cell *cell)
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| {
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| 	return -ENOSYS;
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| }
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| 
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| #endif /* CONFIG_NVMEM */
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| 
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| #endif /* NVMEM_H */
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