Re: Yet another ethernet PHY LED control proposal

From: Pavel Machek
Date: Mon Sep 14 2020 - 16:30:40 EST


Hi!

> I have been thinking about another way to implement ABI for HW control
> of ethernet PHY connected LEDs.
>
> This proposal is inspired by the fact that for some time there is a
> movement in the kernel to do transparent HW offloading of things (DSA
> is an example of that).

And it is good proposal.

> So currently we have the `netdev` trigger. When this is enabled for a
> LED, new files will appear in that LED's sysfs directory:
> - `device_name` where user is supposed to write interface name
> - `link` if set to 1, the LED will be ON if the interface is linked
> - `rx` if set to 1, the LED will blink on receive event
> - `tx` if set to 1, the LED will blink on transmit event
> - `interval` specifies duration of the LED blink
>
> Now what is interesting is that almost all combinations of link/rx/tx
> settings are offloadable to a Marvell PHY! (Not to all LEDs, though...)
>
> So what if we abandoned the idea of a `hw` trigger, and instead just
> allowed a LED trigger to be offloadable, if that specific LED supports
> it?
>
> For the HW mode for different speed we can just expand the `link` sysfs
> file ABI, so that if user writes a specific speed to this file, instead
> of just "1", the LED will be on if the interface is linked on that
> specific speed. Or maybe another sysfs file could be used for "light on
> N mbps" setting...
>
> Afterwards we can figure out other possible modes.
>
> What do you think?

If this can be implemented (and it probably can) it is the best
solution :-).

Best regards,
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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