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regmap: Account for register length when chunking 

commit 3981514180 upstream.

Currently, when regmap_raw_write() splits the data, it uses the
max_raw_write value defined for the bus.  For any bus that includes
the target register address in the max_raw_write value, the chunked
transmission will always exceed the maximum transmission length.
To avoid this problem, subtract the length of the register and the
padding from the maximum transmission.

Signed-off-by: Jim Wylder <jwylder@google.com
Link: https://lore.kernel.org/r/20230517152444.3690870-2-jwylder@google.com
Signed-off-by: Mark Brown <broonie@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jim Wylder 2023-05-17 10:20:11 -05:00 committed by Greg Kroah-Hartman
parent cb1cbe430e
commit 608c1f2083
1 changed files with 4 additions and 2 deletions
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6
drivers/base/regmap/regmap.c
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@ -1998,6 +1998,8 @@ int _regmap_raw_write(struct regmap *map, unsigned int reg,
size_t val_count = val_len / val_bytes;
size_t chunk_count, chunk_bytes;
size_t chunk_regs = val_count;
size_t max_data = map->max_raw_write - map->format.reg_bytes -
map->format.pad_bytes;
int ret, i;
if (!val_count)
@ -2005,8 +2007,8 @@ int _regmap_raw_write(struct regmap *map, unsigned int reg,
if (map->use_single_write)
chunk_regs = 1;
else if (map->max_raw_write && val_len > map->max_raw_write)
chunk_regs = map->max_raw_write / val_bytes;
else if (map->max_raw_write && val_len > max_data)
chunk_regs = max_data / val_bytes;
chunk_count = val_count / chunk_regs;
chunk_bytes = chunk_regs * val_bytes;