hwmon: (aquacomputer_d5next) Avoid truncating scaled sensor readings

High Flow Next power is reported in watts. Multiplying the 16-bit value
by one million can overflow both the signed intermediate and the u32
cache. Store power in long, perform the conversion in u64, and clamp to
LONG_MAX. The other existing power conversions fit in a signed 32-bit
value. Return -ENODATA for unavailable power instead of exposing the
stored error as a reading.

The power cache is updated by HID reports without the hwmon read mutex.
Read it once with READ_ONCE() and use that snapshot for both the
availability check and the returned value. Mark the corresponding
updates with WRITE_ONCE() so that the shared accesses are explicit.

Widen the shared current cache to u32. The Aquastream XT conversion to
milliamperes can exceed 65535 mA; clamp its negative conversion results
to zero before assigning to the unsigned cache. This also permits devices
with scaled aggregate currents to store milliamperes directly.

Fixes: aed80bb91de8 ("hwmon: (aquacomputer_d5next) Add support for Aquacomputer High Flow Next")
Cc: stable@vger.kernel.org
Signed-off-by: Vas Zayarskiy <contact@vasily.cc>
Link: https://patch.msgid.link/20260927191316.4137752-2-contact@vasily.cc
[groeck: Dropped obsolete 'Assisted-by: tag]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

0 files changed, 0 insertions, 0 deletions