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Commit afd5550c authored by Jim Wylder's avatar Jim Wylder Committed by Greg Kroah-Hartman
Browse files

regmap: Account for register length when chunking 



commit 3981514180c987a79ea98f0ae06a7cbf58a9ac0f 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: default avatarJim Wylder <jwylder@google.com>
Link: https://lore.kernel.org/r/20230517152444.3690870-2-jwylder@google.com


Signed-off-by: default avatarMark Brown <broonie@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 0f747181

drivers/base/regmap/regmap.c

+4 −2
Original line number Diff line number Diff line
@@ -1825,6 +1825,8 @@ 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)
@@ -1832,8 +1834,8 @@ 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;