regmap: debugfs: Suppress cache for partial register files

The cache is based on the full register map so confuses things if used
for a partial map.

Reported-by: Bard Liao <bardliao@realtek.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/base/regmap/regmap-debugfs.c b/drivers/base/regmap/regmap-debugfs.c
index 23b701f5fd2f..686400994868 100644
--- a/drivers/base/regmap/regmap-debugfs.c
+++ b/drivers/base/regmap/regmap-debugfs.c
@@ -84,6 +84,10 @@ static unsigned int regmap_debugfs_get_dump_start(struct regmap *map,
         unsigned int fpos_offset;
         unsigned int reg_offset;
 
+        /* Suppress the cache if we're using a subrange */
+        if (from)
+                return from;
+
         /*
          * If we don't have a cache build one so we don't have to do a
          * linear scan each time.