Re: [v6 1/2] dt-bindings: Add bindings for aspeed pwm-tach.

[Billy Tsai]

Hi Rob,

On 2021/5/20, 4:20 AM,Rob Herringwrote:

    On Tue, May 18, 2021 at 08:55:16AM +0800, Billy Tsai wrote:
    >   > +        };
    >   > +      };
    >   > +
    >   > +      tach: tach {
    >   > +        compatible = "aspeed,ast2600-tach";

    > Are pwm and tach separate h/w blocks? 

Yes, they are the separate h/w blocks.

    >   > +        #address-cells = <1>;
    >   > +        #size-cells = <0>;
    >   > +        pinctrl-names = "default";
    >   > +        pinctrl-0 = <&pinctrl_tach0_default>;
    >   > +        fan@0 {
    >   > +          reg = <0>;

    > How does one configure which PWM is connected to each fan?
    > Existing bindings use 'reg' for PWM channel and another property for 
    > tach channel. Please don't do something different.

The fan node in this place specifically refers tach pin, maybe I need to change the naming to avoid confusion.
We just focus on the fan properties on this tach channel has nothing to do with pwm.

    > +          aspeed,min-rpm = <1000>;
    > +          aspeed,pulse-pr = <2>;
    > +          aspeed,tach-div = <5>;
    > +        };
    > +      };
    > +    };