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Commit 2ac902ce authored by Mark Brown's avatar Mark Brown
Browse files

regmap: flat: Add flat cache type 



While for I2C and SPI devices the overhead of using rbtree for devices with
only one block of registers is negligible the same isn't always going to
be true for MMIO devices where the I/O costs are very much lower. Cater
for these devices by adding a simple flat array type for them where the
lookups are simple array accesses, taking us right back to the original
ASoC cache implementation.

Thanks to Magnus Damm for the discussion which prompted this.

Signed-off-by: default avatarMark Brown <broonie@opensource.wolfsonmicro.com>
parent a49f0d1e

drivers/base/regmap/Makefile

+1 −1
Original line number Diff line number Diff line 
obj-$(CONFIG_REGMAP) += regmap.o regcache.o

obj-$(CONFIG_REGMAP) += regcache-rbtree.o regcache-lzo.o

obj-$(CONFIG_REGMAP) += regcache-rbtree.o regcache-lzo.o regcache-flat.o

obj-$(CONFIG_DEBUG_FS) += regmap-debugfs.o

obj-$(CONFIG_REGMAP_I2C) += regmap-i2c.o

obj-$(CONFIG_REGMAP_SPI) += regmap-spi.o

drivers/base/regmap/internal.h

+1 −0
Original line number Diff line number Diff line
@@ -177,5 +177,6 @@ int regcache_lookup_reg(struct regmap *map, unsigned int reg); 


extern struct regcache_ops regcache_rbtree_ops;

extern struct regcache_ops regcache_lzo_ops;

extern struct regcache_ops regcache_flat_ops;



#endif

drivers/base/regmap/regcache-flat.c

0 → 100644
+72 −0
Original line number Diff line number Diff line 
/*

 * Register cache access API - flat caching support

 *

 * Copyright 2012 Wolfson Microelectronics plc

 *

 * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 */



#include <linux/slab.h>

#include <linux/device.h>

#include <linux/seq_file.h>



#include "internal.h"



static int regcache_flat_init(struct regmap *map)

{

	int i;

	unsigned int *cache;



	map->cache = kzalloc(sizeof(unsigned int) * (map->max_register + 1),

			     GFP_KERNEL);

	if (!map->cache)

		return -ENOMEM;



	cache = map->cache;



	for (i = 0; i < map->num_reg_defaults; i++)

		cache[map->reg_defaults[i].reg] = map->reg_defaults[i].def;



	return 0;

}



static int regcache_flat_exit(struct regmap *map)

{

	kfree(map->cache);

	map->cache = NULL;



	return 0;

}



static int regcache_flat_read(struct regmap *map,

			      unsigned int reg, unsigned int *value)

{

	unsigned int *cache = map->cache;



	*value = cache[reg];



	return 0;

}



static int regcache_flat_write(struct regmap *map, unsigned int reg,

			       unsigned int value)

{

	unsigned int *cache = map->cache;



	cache[reg] = value;



	return 0;

}



struct regcache_ops regcache_flat_ops = {

	.type = REGCACHE_FLAT,

	.name = "flat",

	.init = regcache_flat_init,

	.exit = regcache_flat_exit,

	.read = regcache_flat_read,

	.write = regcache_flat_write,

};

drivers/base/regmap/regcache.c

+1 −0
Original line number Diff line number Diff line
@@ -22,6 +22,7 @@ 
static const struct regcache_ops *cache_types[] = {

	&regcache_rbtree_ops,

	&regcache_lzo_ops,

	&regcache_flat_ops,

};



static int regcache_hw_init(struct regmap *map)

include/linux/regmap.h

+2 −1
Original line number Diff line number Diff line
@@ -28,7 +28,8 @@ struct regmap_range_cfg; 
enum regcache_type {

	REGCACHE_NONE,

	REGCACHE_RBTREE,

	REGCACHE_COMPRESSED

	REGCACHE_COMPRESSED,

	REGCACHE_FLAT,

};



/**