Re: [v6 2/4] dt-bindings: hwmon: Add ASPEED TACH Control documentation

[Guenter Roeck]

On 6/7/23 23:21, Billy Tsai wrote:
>          > The code says:
>
>          > In Aspeed AST2600 SoC features 16 TACH controllers, with each
>
>          > controller capable of supporting up to 1 input.
>
>          > which is a bit different. I guess there are no examples anymore,
>
>          > but I'd really like to see how this looks like in the devicetree file,
>
>          > and how the driver is supposed to distinguish/select the 16 inputs.
>
> Hi Roeck,
>
> The node in the devicetree file will looks like following:
>
> tach0: tach0@1e610008 {
>
>          compatible = "aspeed,ast2600-tach";
>
>          reg = <0x1e610008 0x8>;
>
>          #address-cells = <1>;
>
>          #size-cells = <0>;
>
>          pinctrl-names = "default";
>
>          pinctrl-0 = <&pinctrl_tach0_default>;
>
>          clocks = <&syscon ASPEED_CLK_AHB>;
>
>          resets = <&syscon ASPEED_RESET_PWM>;
>
>          status = "disabled";
>
> };

Neither reg nor pinctrl is mentioned in the bindings. Maybe that is not needed nowadays,
but I find it confusing.

Either case, it is highly unusual that there would be 16 instances of this device
instead of one. Why is this done ? It doesn't really make sense to me.

Guenter