On Mon, 4 Oct 2021 16:50:09 +0200 Andrew Lunn <andrew@xxxxxxx> wrote: > > Hello Andrew, > > > > I am aware of this, and in fact am working on a proposal for an > > extension of netdev LED extension, to support the different link > > modes. (And also to support for multi-color LEDs.) > > > > But I am not entirely sure whether these different link modes should be > > also definable via device-tree. Are there devices with ethernet LEDs > > dedicated for a specific speed? (i.e. the manufacturer says in the > > documentation of the device, or perhaps on the device's case, that this > > LED shows 100M/1000M link, and that other LED is shows 10M link?) > > If so, that this should be specified in the devicetree, IMO. But are > > such devices common? > > I have a dumb 5 port switch next to me. One port is running at 1G. Its > left green LED is on and blinks with traffic. Another port of the > switch is running at 100Mbps and its right orange LED is on, blinks > for traffic. And there is text on the case saying 10/100 orange, 1G > green. > > I think this is pretty common. You generally do want to know if 10/100 > is being used, it can indicate problems. Same for a 10G port running > at 1G, etc. OK then. I will work no a proposal for device tree bindings for this. > > And what about multi-color LEDs? There are ethernet ports where one LED > > is red-green, and so can generate red, green, and yellow color. Should > > device tree also define which color indicates which mode? > > There are two different ways this can be implemented. There can be two > independent LEDs within the same package. So you can generate three > colours. Or there can be two cross connected LEDs within the > package. Apply +ve you get one colour, apply -ve you get a different > colour. Since you cannot apply both -ve and +ve at the same time, you > cannot get both colours at once. > > If you have two independent LEDs, I would define two LEDs in DT. No, we have multicolor LED API which is meant for exactly this situation: a multicolor LED. (I am talking about something like the KJ2518D-262 from http://www.rego.com.tw/product_detail.php?prdt_id=258 which has Green/Orange on left and Yellow on right side. The left Green/Orange LED has 3 pins, and so it can mix the colors into yellow.) > Things get tricky for the two dependency LEDs. Does the LED core have > support for such LEDs? Unfortunately not yet. The multicolor API supports LEDs where the sub-leds are independent. > This is where we need to strike a balance between too simple and too > complex. Implement most of the common features, but don't support > exotic stuff, like two dependency LEDs? I think the best solution here would be a subclass "enumcolor" (or different name), where you can choose between several pre-defined colors. In sysfs you could then do echo 1 >brightness echo green >color echo yellow >color There already are other people who need to register such LEDs. Marek
