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Commit e33fabd3 authored by Anthony Olech's avatar Anthony Olech Committed by Mark Brown
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regmap: new API regmap_multi_reg_write() definition 



New API regmap_multi_reg_write() is defined that allows a set of reg,val
pairs to be written to a I2C client device as one block transfer from the
point of view of a single I2C master system.

A simple demonstration implementation is included that just splits the
block write request into a sequence of single register writes.

The implementation will be modified later to support those I2C clients
that implement the alternative non-standard MULTIWRITE block write mode
so to achieve a single I2C transfer that will be atomic even in multiple
I2C master systems.

Signed-off-by: default avatarAnthony Olech <anthony.olech.opensource@diasemi.com>
Signed-off-by: default avatarDavid Dajun Chen <david.chen@diasemi.com>
Signed-off-by: default avatarMark Brown <broonie@linaro.org>
parent 61e6cfa8

drivers/base/regmap/regmap.c

+41 −0
Original line number Diff line number Diff line
@@ -1439,6 +1439,47 @@ out: 
}

EXPORT_SYMBOL_GPL(regmap_bulk_write);



/*

 * regmap_multi_reg_write(): Write multiple registers to the device

 *

 * where the set of register are supplied in any order

 *

 * @map: Register map to write to

 * @regs: Array of structures containing register,value to be written

 * @num_regs: Number of registers to write

 *

 * This function is intended to be used for writing a large block of data

 * atomically to the device in single transfer for those I2C client devices

 * that implement this alternative block write mode.

 *

 * A value of zero will be returned on success, a negative errno will

 * be returned in error cases.

 */

int regmap_multi_reg_write(struct regmap *map, struct reg_default *regs,

				int num_regs)

{

	int ret = 0, i;



	for (i = 0; i < num_regs; i++) {

		int reg = regs[i].reg;

		if (reg % map->reg_stride)

			return -EINVAL;

	}



	map->lock(map->lock_arg);



	for (i = 0; i < num_regs; i++) {

		ret = _regmap_write(map, regs[i].reg, regs[i].def);

		if (ret != 0)

			goto out;

	}

out:

	map->unlock(map->lock_arg);



	return ret;

}

EXPORT_SYMBOL_GPL(regmap_multi_reg_write);



/**

 * regmap_raw_write_async(): Write raw values to one or more registers

 *                           asynchronously

include/linux/regmap.h

+2 −0
Original line number Diff line number Diff line
@@ -378,6 +378,8 @@ int regmap_raw_write(struct regmap *map, unsigned int reg, 
		     const void *val, size_t val_len);

int regmap_bulk_write(struct regmap *map, unsigned int reg, const void *val,

			size_t val_count);

int regmap_multi_reg_write(struct regmap *map, struct reg_default *regs,

			int num_regs);

int regmap_raw_write_async(struct regmap *map, unsigned int reg,

			   const void *val, size_t val_len);

int regmap_read(struct regmap *map, unsigned int reg, unsigned int *val);