@@ -285,6 +295,9 @@ static int max31790_write_fan(struct device
*dev, u32 attr, int channel,
MAX31790_REG_FAN_CONFIG(channel),
data->fan_config[channel]);
break;
+ case hwmon_fan_pulses:
+ data->pulses[channel] = val;
+ break;
This needs input validation, otherwise it's possible to write 0 in there
and you get a division-by-zero in the kernel context:
[102109.999968] Division by zero in kernel.
[102110.003917] CPU: 1 PID: 27590 Comm: cat Not tainted 5.9.3-cla-cfb #42
[102110.010462] Hardware name: Marvell Armada 380/385 (Device Tree)
[102110.016497] [<c010f16c>] (unwind_backtrace) from [<c010ae40>]
(show_stack+0x10/0x14)
[102110.024355] [<c010ae40>] (show_stack) from [<c083ba30>]
(dump_stack+0x94/0xa8)
[102110.031689] [<c083ba30>] (dump_stack) from [<c083a3fc>]
(Ldiv0+0x8/0x2c)
[102110.038499] [<c083a3fc>] (Ldiv0) from [<c064c1ac>]
(max31790_read+0x174/0x204)
[102110.045836] [<c064c1ac>] (max31790_read) from [<c0646fdc>]
(hwmon_attr_show+0x44/0x138)
...
A similar error can also happen when setting the fan speed to 0 RPM.
That's, however, not an error caused by this patch series AFAIK. I *think*
that RPM_TO_REG should be changed to check if `rpm` is 0, and if so, set
the register directly to the maximal value of 0x7ff (in another patch).
With kind regards,
Jan
