netdev - Re: [PATCH 1/2] dt-bindings: dp83867: define ti,ledX-active-low properties

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Date:   Fri, 4 Nov 2022 08:17:44 +0100
From:   Rasmus Villemoes <linux@...musvillemoes.dk>
To:     Andrew Lunn <andrew@...n.ch>
Cc:     Heiner Kallweit <hkallweit1@...il.com>,
        Russell King <linux@...linux.org.uk>, netdev@...r.kernel.org,
        devicetree@...r.kernel.org, Rob Herring <robh+dt@...nel.org>
Subject: Re: [PATCH 1/2] dt-bindings: dp83867: define ti,ledX-active-low
 properties

On 03/11/2022 23.17, Andrew Lunn wrote:
> On Thu, Nov 03, 2022 at 03:31:17PM +0100, Rasmus Villemoes wrote:
>> The dp83867 has three LED_X pins that can be used to drive LEDs. They
>> are by default driven active high, but on some boards the reverse is
>> needed. Add bindings to allow a board to specify that they should be
>> active low.
> 
> Somebody really does need to finish the PHY LEDs via /sys/class/leds.
> It looks like this would then be a reasonable standard property:
> active-low, not a vendor property.
> 
> Please help out with the PHY LEDs patches.

So how do you imagine this to work in DT? Should the dp83867 phy node
grow a subnode like this?

  leds {
    #address-cells = <1>;
    #size-cells = <0>;

    led@0 {
      reg = <0>;
      active-low;
    };
    led@2 {
      reg = <2>;
      active-low;
    };
  };

Since the phy drives the leds automatically based on (by default)
link/activity, there's not really any need for a separate LED driver nor
do I see what would be gained by somehow listing the LEDs in
/sys/class/leds. Please expand.

Rasmus