tree 701d2bd8e4b8124d96f27c4da6ccbb1f50574669
parent a69a6ebd036a6c7edf89db09ca358927c158dbe4
author Guenter Roeck <linux@roeck-us.net> 1480904125 -0800
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1484217566 +0100

hwmon: (nct7802) Fix overflows seen when writing into limit attributes

commit c0d04e9112ad59d73f23f3b0f6726c5e798dfcbf upstream.

Fix overflows seen when writing voltage and temperature limit attributes.

The value passed to DIV_ROUND_CLOSEST() needs to be clamped, and the
value parameter passed to nct7802_write_fan_min() is an unsigned long.

Also, writing values larger than 2700000 into a fan limit attribute results
in writing 0 into the chip's limit registers. The exact behavior when
writing this value is unspecified. For consistency, report a limit of
1350000 if the chip register reads 0. This may be wrong, and the chip
behavior should be verified with the actual chip, but it is better than
reporting a value of 0 (which, when written, results in writing a value
of 0x1fff into the chip register).

Fixes: 3434f3783580 ("hwmon: Driver for Nuvoton NCT7802Y")
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>