Re: [hwmon-next PATCH v4 3/4] hwmon: (adt7470) Expose fan control via PWM framework

[Guenter Roeck]

On 7/29/26 12:05, Luiz Angelo Daros de Luca wrote:
> Hi Guenter, Uwe,
>
> Thank you both for the detailed reviews. I hope I'll address all the
> points discussed in the next version.
>
> > > > No, I won't accept this. It has to be either or. A pwm channel modeled as pwm
> > > > subsystem channel must not be visible via hwmon attributes.
> > >
> > > I didn't look in detail, but maybe my red line is a bit more lax. IMHO
> > > it's not OK to be able to modify a setting that results from pushing
> > > hwmon knobs using PWM operations or vice-versa. Switching between
> > > exclusive use at runtime is IMHO ok.
> > It is my call to make, and my call is either-or to avoid confusion.
>
> Guenter, I agree and followed your strict "either-or" directive. If
> the device is bound via the PWM framework (i.e., #pwm-cells is present
> in the DT), the driver completely hides all legacy hwmon PWM
> attributes.

Yes, that is what I am looking for, assuming it is per channel.
We do not want to unconditionally disable automatic fan control support
by the chip just because a single channel is used as generic PWM controller.

> One implementation detail: currently, the driver hides the hwmon
> attributes only if #pwm-cells is present and IS_REACHABLE(CONFIG_PWM)
> is true. If the DTS has #pwm-cells but the PWM framework is disabled
> in the kernel, it emits a dev_warn and falls back to exposing the
> hwmon attributes. Please let me know if you would prefer to
> unconditionally hide the hwmon attributes merely based on the presence
> of the DT property, regardless of the CONFIG_PWM state.
No, that would be overkill.

Thanks,
Guenter