regmap: cache: Do not fail silently from regcache_sync calls

Call stack of regcache_sync calls may not emit any error message even if
operation was cancelled due an error in I/O driver. One such a silent error
is for instance if I2C bus driver doesn't receive ACK from the I2C device
and returns -EREMOTEIO.

Since many users of regcache_sync() don't check and print the error there is
no any indication that HW registers are potentially out of sync.

Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 11 insertions, 2 deletions

diff --git a/drivers/base/regmap/regcache.c b/drivers/base/regmap/regcache.c
index 29b4128da0b0..da7b3bfd4d7f 100644
--- a/drivers/base/regmap/regcache.c
+++ b/drivers/base/regmap/regcache.c
@@ -269,8 +269,11 @@ static int regcache_default_sync(struct regmap *map, unsigned int min,
                 map->cache_bypass = 1;
                 ret = _regmap_write(map, reg, val);
                 map->cache_bypass = 0;
-                if (ret)
+                if (ret) {
+                        dev_err(map->dev, "Unable to sync register %#x. %d\n",
+                                reg, ret);
                         return ret;
+                }
                 dev_dbg(map->dev, "Synced register %#x, value %#x\n", reg, val);
         }
 
@@ -615,8 +618,11 @@ static int regcache_sync_block_single(struct regmap *map, void *block,
                 ret = _regmap_write(map, regtmp, val);
 
                 map->cache_bypass = 0;
-                if (ret != 0)
+                if (ret != 0) {
+                        dev_err(map->dev, "Unable to sync register %#x. %d\n",
+                                regtmp, ret);
                         return ret;
+                }
                 dev_dbg(map->dev, "Synced register %#x, value %#x\n",
                         regtmp, val);
         }
@@ -641,6 +647,9 @@ static int regcache_sync_block_raw_flush(struct regmap *map, const void **data,
         map->cache_bypass = 1;
 
         ret = _regmap_raw_write(map, base, *data, count * val_bytes);
+        if (ret)
+                dev_err(map->dev, "Unable to sync registers %#x-%#x. %d\n",
+                        base, cur - map->reg_stride, ret);
 
         map->cache_bypass = 0;