regmap: Introduce caching support

This patch introduces caching support for regmap.  The regcache API
has evolved essentially out of ASoC soc-cache so most of the actual
caching types (except LZO) have been tested in the past.

The purpose of regcache is to optimize in time and space the handling
of register caches.  Time optimization is achieved by not having to go
over a slow bus like I2C to read the value of a register, instead it is
cached locally in memory and can be retrieved faster.  Regarding space
optimization, some of the cache types are better at packing the caches,
for e.g. the rbtree and the LZO caches.  By doing this the sacrifice in
time still wins over doing I2C transactions.

Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Tested-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

1 files changed, 52 insertions, 0 deletions

diff --git a/drivers/base/regmap/internal.h b/drivers/base/regmap/internal.h
index a98493c..615f558 100644
--- a/drivers/base/regmap/internal.h
+++ b/drivers/base/regmap/internal.h
@@ -17,6 +17,7 @@
 #include <linux/fs.h>
 
 struct regmap;
+struct regcache_ops;
 
 struct regmap_format {
 	size_t buf_size;
@@ -49,6 +50,40 @@ struct regmap {
 
 	u8 read_flag_mask;
 	u8 write_flag_mask;
+
+	/* regcache specific members */
+	const struct regcache_ops *cache_ops;
+	enum regcache_type cache_type;
+
+	/* number of bytes in reg_defaults_raw */
+	unsigned int cache_size_raw;
+	/* number of bytes per word in reg_defaults_raw */
+	unsigned int cache_word_size;
+	/* number of entries in reg_defaults */
+	unsigned int num_reg_defaults;
+	/* number of entries in reg_defaults_raw */
+	unsigned int num_reg_defaults_raw;
+
+	/* if set, only the cache is modified not the HW */
+	unsigned int cache_only:1;
+	/* if set, only the HW is modified not the cache */
+	unsigned int cache_bypass:1;
+	/* if set, remember to free reg_defaults_raw */
+	unsigned int cache_free:1;
+
+	struct reg_default *reg_defaults;
+	const void *reg_defaults_raw;
+	void *cache;
+};
+
+struct regcache_ops {
+	const char *name;
+	enum regcache_type type;
+	int (*init)(struct regmap *map);
+	int (*exit)(struct regmap *map);
+	int (*read)(struct regmap *map, unsigned int reg, unsigned int *value);
+	int (*write)(struct regmap *map, unsigned int reg, unsigned int value);
+	int (*sync)(struct regmap *map);
 };
 
 bool regmap_writeable(struct regmap *map, unsigned int reg);
@@ -66,4 +101,21 @@ static inline void regmap_debugfs_init(struct regmap *map) { }
 static inline void regmap_debugfs_exit(struct regmap *map) { }
 #endif
 
+/* regcache core declarations */
+int regcache_init(struct regmap *map);
+void regcache_exit(struct regmap *map);
+int regcache_read(struct regmap *map,
+		       unsigned int reg, unsigned int *value);
+int regcache_write(struct regmap *map,
+			unsigned int reg, unsigned int value);
+int regcache_sync(struct regmap *map);
+
+unsigned int regcache_get_val(const void *base, unsigned int idx,
+			      unsigned int word_size);
+bool regcache_set_val(void *base, unsigned int idx,
+		      unsigned int val, unsigned int word_size);
+int regcache_lookup_reg(struct regmap *map, unsigned int reg);
+int regcache_insert_reg(struct regmap *map, unsigned int reg,
+			unsigned int val);
+
 #endif