3f3576e25b
[ Upstream commit 8d655e65237643c48ada2c131b83679bf1105373 ]
When probing the ucd90320 access to some of the registers randomly fails.
Sometimes it NACKs a transfer, sometimes it returns just random data and
the PEC check fails.
Experimentation shows that this seems to be triggered by a register access
directly back to back with a previous register write. Experimentation also
shows that inserting a small delay after register writes makes the issue go
away.
Use a similar solution to what the max15301 driver does to solve the same
problem. Create a custom set of bus read and write functions that make sure
that the delay is added.
Fixes: a470f11c5ba2 ("hwmon: (pmbus/ucd9000) Add support for UCD90320 Power Sequencer")
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Link: https://lore.kernel.org/r/20230312160312.2227405-1-lars@metafoo.de
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel
============
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