Hi Rob, On 2022/11/3, 3:39 PM, "Billy Tsai" <billy_tsai@xxxxxxxxxxxxxx> wrote: On 2022/11/3, 2:19 AM, "Rob Herring" <robh@xxxxxxxxxx> wrote: On Tue, Nov 1, 2022 at 10:21 PM Billy Tsai <billy_tsai@xxxxxxxxxxxxxx> wrote: > > That all sounds like requirements that you have which you should > > ensure the fan binding can support. > > I've already said to use the PWM binding in the fan binding exactly > > for the purpose of hooking up the PWMs to other things. Whether the > > tach controller is useful for something other than fans, I don't know. > > Seems less likely. The max6639 also has a tach controller. So if other > > uses are possible for you, then it could be possible for any other h/w > > like the max6639. > The linux kernel already have the similar binding: > https://github.com/torvalds/linux/blob/master/Documentation/devicetree/bindings/hwmon/pwm-fan.txt > Therefore, I want to reuse it and the pwm-fan.c instead of creating another similar fan binding and driver. > I am referring to the following files: > https://github.com/torvalds/linux/blob/master/Documentation/devicetree/bindings/mfd/kontron%2Csl28cpld.yaml > https://github.com/torvalds/linux/blob/master/Documentation/devicetree/bindings/pwm/kontron%2Csl28cpld-pwm.yaml > https://github.com/torvalds/linux/blob/master/Documentation/devicetree/bindings/hwmon/kontron%2Csl28cpld-hwmon.yaml > It will also reuse the pwm-fan instead creating it own pwm-fan binding for their hwmon(tach). > https://github.com/torvalds/linux/blob/master/arch/arm64/boot/dts/freescale/fsl-ls1028a-kontron-sl28-var3-ads2.dts#L20 Do you have any sugguest about the binding like the link above? We can just creat the pure PWM provider and use the pwm-fan as the common fan binding instead of creating another fan-common.yaml. Thanks Best Regards, Billy Tsai