regmap: Supply ranges to the sync operations

In order to allow us to support partial sync operations add minimum and
maximum register arguments to the sync operation and update the rbtree
and lzo caches to use this new information. The LZO implementation is
obviously not good, we could exit the iteration earlier, but there may
be room for more wide reaching optimisation there.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

drivers/base/regmap/internal.h

@@ -87,7 +87,7 @@ struct regcache_ops {
 	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);
+	int (*sync)(struct regmap *map, unsigned int min, unsigned int max);
 };
 
 bool regmap_writeable(struct regmap *map, unsigned int reg);

drivers/base/regmap/regcache-lzo.c

@@ -331,7 +331,8 @@ static int regcache_lzo_write(struct regmap *map,
 	return ret;
 }
 
-static int regcache_lzo_sync(struct regmap *map)
+static int regcache_lzo_sync(struct regmap *map, unsigned int min,
+			     unsigned int max)
 {
 	struct regcache_lzo_ctx **lzo_blocks;
 	unsigned int val;
@@ -339,7 +340,12 @@ static int regcache_lzo_sync(struct regmap *map)
 	int ret;
 
 	lzo_blocks = map->cache;
-	for_each_set_bit(i, lzo_blocks[0]->sync_bmp, lzo_blocks[0]->sync_bmp_nbits) {
+	i = min;
+	for_each_set_bit_from(i, lzo_blocks[0]->sync_bmp,
+			      lzo_blocks[0]->sync_bmp_nbits) {
+		if (i > max)
+			continue;
+
 		ret = regcache_read(map, i, &val);
 		if (ret)
 			return ret;

drivers/base/regmap/regcache-rbtree.c

@@ -357,7 +357,8 @@ static int regcache_rbtree_write(struct regmap *map, unsigned int reg,
 	return 0;
 }
 
-static int regcache_rbtree_sync(struct regmap *map)
+static int regcache_rbtree_sync(struct regmap *map, unsigned int min,
+				unsigned int max)
 {
 	struct regcache_rbtree_ctx *rbtree_ctx;
 	struct rb_node *node;
@@ -365,12 +366,30 @@ static int regcache_rbtree_sync(struct regmap *map)
 	unsigned int regtmp;
 	unsigned int val;
 	int ret;
-	int i;
+	int i, base, end;
 
 	rbtree_ctx = map->cache;
 	for (node = rb_first(&rbtree_ctx->root); node; node = rb_next(node)) {
 		rbnode = rb_entry(node, struct regcache_rbtree_node, node);
-		for (i = 0; i < rbnode->blklen; i++) {
+
+		if (rbnode->base_reg < min)
+			continue;
+		if (rbnode->base_reg > max)
+			break;
+		if (rbnode->base_reg + rbnode->blklen < min)
+			continue;
+
+		if (min < rbnode->base_reg + rbnode->blklen)
+			base = min - rbnode->base_reg;
+		else
+			base = 0;
+
+		if (max < rbnode->base_reg + rbnode->blklen)
+			end = rbnode->base_reg + rbnode->blklen - max;
+		else
+			end = rbnode->blklen;
+
+		for (i = base; i < end; i++) {
 			regtmp = rbnode->base_reg + i;
 			val = regcache_rbtree_get_register(rbnode, i,
 							   map->cache_word_size);

drivers/base/regmap/regcache.c

@@ -283,7 +283,7 @@ int regcache_sync(struct regmap *map)
 	}
 	map->cache_bypass = 0;
 
-	ret = map->cache_ops->sync(map);
+	ret = map->cache_ops->sync(map, 0, map->max_register);
 
 	if (ret == 0)
 		map->cache_dirty = false;