[PATCH 2/2] regmap: cache: Don't attempt to sync non-writeable registers.

[Dylan Reid <dgreid@chromium.org>]

In the regcache_default_sync, if a register isn't writeable, then
_regmap_write will return an error and the rest of the sync will be
aborted.  Avoid this by checking if a register is writeable before
trying to sync it.

Signed-off-by: Dylan Reid <dgreid@chromium.org>
---
 drivers/base/regmap/regcache.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/base/regmap/regcache.c b/drivers/base/regmap/regcache.c
index 44af125..29b4128 100644
--- a/drivers/base/regmap/regcache.c
+++ b/drivers/base/regmap/regcache.c
@@ -253,7 +253,8 @@ static int regcache_default_sync(struct regmap *map, unsigned int min,
 		unsigned int val;
 		int ret;
 
-		if (regmap_volatile(map, reg))
+		if (regmap_volatile(map, reg) ||
+		    !regmap_writeable(map, reg))
 			continue;
 
 		ret = regcache_read(map, reg, &val);
-- 
1.8.1.3.605.g02339dd