Re: [PATCH v5 2/5] hwmon: (max31790) Fix and split pwm*_enable

From: Jan Kundrát
Date: Wed May 19 2021 - 05:20:14 EST


As it turns out, even the current code doesn't really work for fans 7..12.
sr = get_tach_period(data->fan_dynamics[channel]);
However, the data->fan_dynamics array has only 6 entries, not 12, so
reading fan[7-12]_input will result in bad/random values.

Hi Guenter, I'm Vaclav's colleague. The chip can indeed reconfigure each PWMOUT pin either as a PWM output or as a TACH input, but that's not something that's correctly implemented in the current code, and we have no use for that either (and we cannot test that on our PCBs easily, we do not have the manufacturer's eval kit).

It looks to me that the original bug is that the current docs mention 12 fan inputs. Would you be OK with a patch series which fixes the docs so that the chip always exports 6 TACH inputs and 6 PWMOUT channels?

Cheers,
Jan