Hi Guenter,
On 6/28/24 5:13 PM, Guenter Roeck wrote:
After setting fan1_target and setting pwm1_enable to 4,
the fan controller tries to achieve the requested fan speed.
There's something in the docs (section `Software-RPM Control Mode (Fan
Speed Regulator`) that rubs me the wrong way though.
"""
When the TACH-MODE bit (bit 1 of
0x02) is cleared ('0'), the duty cycle of PWM-Out is forced to 30% when
the calculated desired value of duty
cycle is less than 30%. Therefore, the TACH setting must be not greater
than the value corresponding to the
RPM for 30% duty cycle.
"""
TACH-MODE is never modified in the driver, so its default value prevails: 0.
I'm wondering if there isn't something we need to do to make sure we're
not under those 30% for TACH-Low-Limit/TACH-High-Limit/TACH-SETTING?
Forbid the user to write (or clamp instead) <30% duty cycle. Forbid the
user to select mode 4 if current values are <30% duty cycle, or update
them to be >=30%?
Otherwise, looking good to me,
Cheers,
Quentin
