linux-kernel - Re: [PATCH RFC net-next] net: phy: always set polarity

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Message-ID: <ZwFggnUO-vAXr2v_@makrotopia.org>
Date: Sat, 5 Oct 2024 16:51:30 +0100
From: Daniel Golle <daniel@...rotopia.org>
To: Andrew Lunn <andrew@...n.ch>
Cc: Heiner Kallweit <hkallweit1@...il.com>,
	Russell King <linux@...linux.org.uk>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
	Christian Marangi <ansuelsmth@...il.com>, netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH RFC net-next] net: phy: always set polarity_modes if op
 is supported

On Sat, Oct 05, 2024 at 04:17:56PM +0200, Andrew Lunn wrote:
> > I'll add "active-high" as an additional property then, as I found out
> > that both, Aquantia and Intel/MaxLinear are technically speaking
> > active-low by default (ie. after reset) and what we need to set is a
> > property setting the LED to be driven active-high (ie. driving VDD
> > rather than GND) instead. I hope it's not too late to make this change
> > also for the Aquantia driver.
> 
> Adding a new property should not affect backwards compatibility, so it
> should be safe to merge at any time.

Ok, I will proceed in that direction then and post a patch shortly.
My intial assumption that absence of 'active-low' would always imply
the LED being driven active-high was due to the commit description of
the introduction of the active-low property:

commit c94d1783136eb66f2a464a6891a32eeb55eaeacc
Author: Christian Marangi <ansuelsmth@...il.com>
Date:   Thu Jan 25 21:36:57 2024 +0100

    dt-bindings: net: phy: Make LED active-low property common

    Move LED active-low property to common.yaml. This property is currently
    defined multiple times by bcm LEDs. This property will now be supported
    in a generic way for PHY LEDs with the use of a generic function.

    With active-low bool property not defined, active-high is always
    assumed.

    Signed-off-by: Christian Marangi <ansuelsmth@...il.com>
    Reviewed-by: Andrew Lunn <andrew@...n.ch>
    Acked-by: Lee Jones <lee@...nel.org>
    Reviewed-by: Rob Herring <robh@...nel.org>
    Link: https://lore.kernel.org/r/20240125203702.4552-2-ansuelsmth@gmail.com
    Signed-off-by: Jakub Kicinski <kuba@...nel.org>


However, that's not what the code did in the end, it would be either
"set active-low" or "don't touch".