regmap: Drop early readability check

We have some drivers that have a use case for cached write only
registers, doing read/modify/writes on read only registers in order to
work more easily with bitfields.  Go back to trying the cache before we
check if we can read from the device.

Fixes: eab5abdeb79f0 ("regmap: Check for register readability before checking cache during read")
Reported-by: Konrad Dybcio <konradybcio@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230615-regmap-drop-early-readability-v1-1-8135094362de@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index fad66b3..89a7f1c 100644 (file)
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -2897,9 +2897,6 @@ static int _regmap_read(struct regmap *map, unsigned int reg,
        int ret;
        void *context = _regmap_map_get_context(map);
 
-       if (!regmap_readable(map, reg))
-               return -EIO;
-
        if (!map->cache_bypass) {
                ret = regcache_read(map, reg, val);
                if (ret == 0)
@@ -2909,6 +2906,9 @@ static int _regmap_read(struct regmap *map, unsigned int reg,
        if (map->cache_only)
                return -EBUSY;
 
+       if (!regmap_readable(map, reg))
+               return -EIO;
+
        ret = map->reg_read(context, reg, val);
        if (ret == 0) {
                if (regmap_should_log(map))