regmap: Account for register length when chunking - Linux-stable-mirror

2 Jun 2023


      Requesting that this regmap fix be cherry picked into the active
stable releases 5.15 and later (5.15 being the earliest I was able
to test).
Commit 3981514180c987a79ea98f0ae06a7cbf58a9ac0f fixes a error in
_regmap_raw_write() when chunking a transmission larger than the
maximum write size for the bus and when bus writes the address
and any padding along with the data.
Jim
The original commit message is:
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commit 3981514180c987a79ea98f0ae06a7cbf58a9ac0f
Author: Jim Wylder jwylder@google.com
Date:   Wed May 17 10:20:11 2023 -0500
regmap: Account for register length when chunking
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
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