[v2 1/3] dt-bindings: Add bindings for aspeed pwm-tach.

Billy Tsai billy_tsai at aspeedtech.com
Mon Nov 14 19:26:49 AEDT 2022

Hi Rob,

On 2022/11/3, 3:39 PM, "Billy Tsai" <billy_tsai at aspeedtech.com> wrote:

    On 2022/11/3, 2:19 AM, "Rob Herring" <robh at kernel.org> wrote:

        On Tue, Nov 1, 2022 at 10:21 PM Billy Tsai <billy_tsai at aspeedtech.com> 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.


Best Regards,
Billy Tsai

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