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