hwmon: (pwm-fan) Ensure that calculation doesn't discard big period values
With MAX_PWM being defined to 255 the code
unsigned long period;
...
period = ctx->pwm->args.period;
state.duty_cycle = DIV_ROUND_UP(pwm * (period - 1), MAX_PWM);
calculates a too small value for duty_cycle if the configured period is
big (either by discarding the 64 bit value ctx->pwm->args.period or by
overflowing the multiplication). As this results in a too slow fan and
so maybe an overheating machine better be safe than sorry and error out
in .probe.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20201215092031.152243-1-u.kleine-koenig@pengutronix.de
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
1 file changed
