max17040_get_vcell() and max17040_get_soc() ignore errors returned by
regmap_read(). When an I2C transfer fails, the uninitialized register
value is converted and reported to userspace as a valid voltage or state
of charge. The polling worker can also replace the cached state of charge
with the bogus value and emit a spurious change event.
Propagate read errors through the power supply get_property callback and
keep the last valid cached state of charge when polling fails.
Fixes: c6f4a42de6 ("Add MAX17040 Fuel Gauge driver")
Cc: stable@vger.kernel.org
Signed-off-by: Jianing Li <m13940358460@163.com>
Link: https://patch.msgid.link/20260727064825.948-1-m13940358460@163.com
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>