The regmap_debugfs_get_dump_start() function maps from a file offset to the register that can be found at that position in the file. This is done using a look-up table. Commit d6814a7d ("regmap: debugfs: Suppress cache for partial register files") added a check to bypass the look-up table for partial register files, since the offsets in that table are only correct for the full register file. The check incorrectly uses the file offset instead of the register base address and returns it. This will cause the file offset to be interpreted as a register address which will result in a incorrect output from the registers file for all reads except at position 0.
The issue can easily be reproduced by doing small reads the registers file, e.g. `dd if=registers bs=10 count=5`. Signed-off-by: Lars-Peter Clausen <l...@metafoo.de> --- drivers/base/regmap/regmap-debugfs.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/base/regmap/regmap-debugfs.c b/drivers/base/regmap/regmap-debugfs.c index 5349575..6c2652a 100644 --- a/drivers/base/regmap/regmap-debugfs.c +++ b/drivers/base/regmap/regmap-debugfs.c @@ -85,8 +85,8 @@ static unsigned int regmap_debugfs_get_dump_start(struct regmap *map, unsigned int reg_offset; /* Suppress the cache if we're using a subrange */ - if (from) - return from; + if (base) + return base; /* * If we don't have a cache build one so we don't have to do a -- 1.8.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/