regmap: Add the indexed cache support

This is the simplest form of a cache available in regcache.  Any
registers whose default value is 0 are ignored.  If any of those
registers are modified in the future, they will be placed in the
cache on demand.  The cache layout is essentially using the provided
register defaults by the regcache core directly and does not re-map
it to another representation.

Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

1 files changed, 65 insertions, 0 deletions

diff --git a/drivers/base/regmap/regcache-indexed.c b/drivers/base/regmap/regcache-indexed.c
new file mode 100644
index 000000000000..ff8b44ce044b
--- /dev/null
+++ b/drivers/base/regmap/regcache-indexed.c
@@ -0,0 +1,65 @@
+/*
+ * Register cache access API - indexed caching support
+ *
+ * Copyright 2011 Wolfson Microelectronics plc
+ *
+ * Author: Dimitris Papastamos <dp@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 "internal.h"
+
+static int regcache_indexed_read(struct regmap *map, unsigned int reg,
+				 unsigned int *value)
+{
+	int ret;
+
+	ret = regcache_lookup_reg(map, reg);
+	if (ret < 0)
+		*value = 0;
+	else
+		*value = map->reg_defaults[ret].def;
+	return 0;
+}
+
+static int regcache_indexed_write(struct regmap *map, unsigned int reg,
+				  unsigned int value)
+{
+	int ret;
+
+	ret = regcache_lookup_reg(map, reg);
+	if (ret < 0)
+		return regcache_insert_reg(map, reg, value);
+	map->reg_defaults[ret].def = value;
+	return 0;
+}
+
+static int regcache_indexed_sync(struct regmap *map)
+{
+	int i;
+	int ret;
+
+	for (i = 0; i < map->num_reg_defaults; i++) {
+		ret = regmap_write(map, map->reg_defaults[i].reg,
+				   map->reg_defaults[i].def);
+		if (ret < 0)
+			return ret;
+		dev_dbg(map->dev, "Synced register %#x, value %#x\n",
+			map->reg_defaults[i].reg,
+			map->reg_defaults[i].def);
+	}
+	return 0;
+}
+
+struct regcache_ops regcache_indexed_ops = {
+	.type = REGCACHE_INDEXED,
+	.name = "indexed",
+	.read = regcache_indexed_read,
+	.write = regcache_indexed_write,
+	.sync = regcache_indexed_sync
+};