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Subject[PATCH] regmap: cache: Do not fail silently from regcache_sync calls
Date
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>
---
I noticed this silent failure when doing commit f4821e8e8e95
("ASoC: rt5640: Do not allow regmap to use bulk read-write operations") but
forgot to send a patch. I was thinking should the error prints be in lower
level, e.g. _regmap_raw_write, but maybe it's good to have sync errors
printed explicitly?
---
drivers/base/regmap/regcache.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/base/regmap/regcache.c b/drivers/base/regmap/regcache.c
index 5617da6dc898..f1280dc356d0 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;

--
2.1.0


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