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Date: Mon, 6 May 2024 09:59:25 +0100
From: Daniel Golle <daniel@makrotopia.org>
To: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Cc: Frank Wunderlich <linux@fw-web.de>, Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Michael Turquette <mturquette@baylibre.com>,
	Stephen Boyd <sboyd@kernel.org>, Pavel Machek <pavel@ucw.cz>,
	Lee Jones <lee@kernel.org>, "David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Matthias Brugger <matthias.bgg@gmail.com>,
	AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>,
	devicetree@vger.kernel.org, Tianling Shen <cnsztl@immortalwrt.org>,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-mediatek@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org,
	Eric Woudstra <ericwouds@gmail.com>, linux-clk@vger.kernel.org,
	linux-leds@vger.kernel.org
Subject: Re: [RFC v1 1/5] dt-bindings: leds: add led trigger netdev
Message-ID: <Zjib7STAHIikWnLp@makrotopia.org>
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 <20240505164549.65644-2-linux@fw-web.de>
 <8e9fd4c9-f537-4413-b8c8-988b001b64c0@linaro.org>
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In-Reply-To: <8e9fd4c9-f537-4413-b8c8-988b001b64c0@linaro.org>

On Mon, May 06, 2024 at 10:18:09AM +0200, Krzysztof Kozlowski wrote:
> On 05/05/2024 18:45, Frank Wunderlich wrote:
> > From: Frank Wunderlich <frank-w@public-files.de>
> > 
> > Add led trigger implemented with config-symbol LEDS_TRIGGER_NETDEV to
> > binding.
> > 
> > Signed-off-by: Frank Wunderlich <frank-w@public-files.de>
> > ---
> >  Documentation/devicetree/bindings/leds/common.yaml | 2 ++
> >  1 file changed, 2 insertions(+)
> > 
> > diff --git a/Documentation/devicetree/bindings/leds/common.yaml b/Documentation/devicetree/bindings/leds/common.yaml
> > index 8a3c2398b10c..bf9a101e4d42 100644
> > --- a/Documentation/devicetree/bindings/leds/common.yaml
> > +++ b/Documentation/devicetree/bindings/leds/common.yaml
> > @@ -113,6 +113,8 @@ properties:
> >              # LED indicates NAND memory activity (deprecated),
> >              # in new implementations use "mtd"
> >            - nand-disk
> > +            # LED indicates network activity
> > +          - netdev
> 
> "dev" is redundant (there is no flash-dev or usb-host-dev). Two network
> interfaces are already provided, so your commit msg must provide
> rationale why this is not enough and why this is useful/needed.

Also note that using 'netdev' assigned via DT via linux,default-trigger
currently doesn't work well. This is because the assignment of the trigger
from DT happens when the PHY is being attached initially, and that's
**before** the network device is registered with Linux.
As a result, LED event offloading is never used if done in this way.

I know that bindings and implementation are two different independent
things, but yet I believe that adding bindings for a feature which doesn't
really work would be misleading.