Hi Mark, the current regcache_sync() has a problem when there are read-only registers that are cached in regmap: it tries to write all cached registers no matter whether it's writable or not, resulting in kernel errors like "Unable to sync register 0x1234. -5".
A quick fix is the patch like below, but obviously it doesn't cover the all cases but only addresses the signle rw. Also, _regmap_write() itself calls again regmap_writeable(), so it's superfluous. Alternatively, we may check -EIO from _regmap_write() and treat as a special case not to show the error. Or, add a parameter to skip regmap_writeable() call. Takashi -- 8< -- From: Takashi Iwai <[email protected]> Subject: [PATCH] regmap: Skip read-only registers in regcache_sync_block_single() regcache_sync() spews warnings when a value was cached for a read-only register as it tries to write all registers no matter whether they are writable or not. This patch fixes (a part of) the problem by adding regmap_writeable() check in regcache_sync_block_single(). Note that the patch covers only the code path using single rw. When a raw block write is used, the problem may still exist. Signed-off-by: Takashi Iwai <[email protected]> --- drivers/base/regmap/regcache.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/base/regmap/regcache.c b/drivers/base/regmap/regcache.c index f373c35f9e1d..30534864735c 100644 --- a/drivers/base/regmap/regcache.c +++ b/drivers/base/regmap/regcache.c @@ -617,6 +617,8 @@ static int regcache_sync_block_single(struct regmap *map, void *block, ret = regcache_lookup_reg(map, regtmp); if (ret >= 0 && val == map->reg_defaults[ret].def) continue; + if (!regmap_writeable(map, regtmp)) + continue; map->cache_bypass = 1; -- 2.3.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
