regmap: fix writes to non incrementing registers

When checking if a register block is writable we must ensure that the
block does not start with or contain a non incrementing register.

Fixes: 8b9f9d4dc511 ("regmap: verify if register is writeable before writing operations")
Signed-off-by: Ben Whitten <ben.whitten@gmail.com>
Link: https://lore.kernel.org/r/20200118205625.14532-1-ben.whitten@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index 19f57cc..59f911e 100644 (file)
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -1488,11 +1488,18 @@ static int _regmap_raw_write_impl(struct regmap *map, unsigned int reg,
 
        WARN_ON(!map->bus);
 
-       /* Check for unwritable registers before we start */
-       for (i = 0; i < val_len / map->format.val_bytes; i++)
-               if (!regmap_writeable(map,
-                                    reg + regmap_get_offset(map, i)))
-                       return -EINVAL;
+       /* Check for unwritable or noinc registers in range
+        * before we start
+        */
+       if (!regmap_writeable_noinc(map, reg)) {
+               for (i = 0; i < val_len / map->format.val_bytes; i++) {
+                       unsigned int element =
+                               reg + regmap_get_offset(map, i);
+                       if (!regmap_writeable(map, element) ||
+                               regmap_writeable_noinc(map, element))
+                               return -EINVAL;
+               }
+       }
 
        if (!map->cache_bypass && map->format.parse_val) {
                unsigned int ival;