[PATCH] regmap: Skip hardware defaults for LZO caches

[Mark Brown]

Saves some I/O when resyncing; we assume that syncs start from the device
reset state.

Signed-off-by: Mark Brown <broonie@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
---
 drivers/base/regmap/regcache-lzo.c |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/drivers/base/regmap/regcache-lzo.c b/drivers/base/regmap/regcache-lzo.c
index 5e964e9..77dc532 100644
--- a/drivers/base/regmap/regcache-lzo.c
+++ b/drivers/base/regmap/regcache-lzo.c
@@ -349,6 +349,12 @@ static int regcache_lzo_sync(struct regmap *map, unsigned int min,
 		ret = regcache_read(map, i, &val);
 		if (ret)
 			return ret;
+
+		/* Is this the hardware default?  If so skip. */
+		ret = regcache_lookup_reg(map, i);
+		if (ret > 0 && val == map->reg_defaults[ret].def)
+			continue;
+
 		map->cache_bypass = 1;
 		ret = _regmap_write(map, i, val);
 		map->cache_bypass = 0;
-- 
1.7.9.1

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