Re: [PATCH 2/3] dt-bindings: leds: Add `excludes` property

On Thu, 14 Oct 2021 12:29:18 +0200
Pavel Machek [off-list ref] wrote:

Hi!

quoted

Some RJ-45 connectors have LEDs wired in the following way:

         LED1
      +--|>|--+
      |       |
  A---+--|<|--+---B
         LED2

With + on A and - on B, LED1 is ON and LED2 is OFF. Inverting the
polarity turns LED1 OFF and LED2 ON.

So these LEDs exclude each other.

Add new `excludes` property to the LED binding. The property is a
phandle-array to all the other LEDs that are excluded by this LED.  

I don't think this belongs to the LED binding.

This is controller limitation, and the driver handling the controller
needs to know about it... so it does not need to learn that from the
LED binding.

It's not necessarily a controller limitation, rather a limitation of
the board (or ethernet connector, in the case of LEDs on an ethernet
connector).

But I guess we could instead document this property in the ethernet PHY
controller binding for a given PHY.

Marek