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From: Luiz Angelo Daros de Luca <luizluca@gmail.com>
Date: Thu, 21 Mar 2024 09:03:34 -0300
Message-ID: <CAJq09z5wXQQQtHJ5TdSz6J+Ov0Hifde25psoWm8EiHxV8c-TYw@mail.gmail.com>
Subject: Re: [PATCH net-next 1/4] dt-bindings: net: dsa: realtek: describe LED usage
To: Andrew Lunn <andrew@lunn.ch>
Cc: Linus Walleij <linus.walleij@linaro.org>, =?UTF-8?Q?Alvin_=C5=A0ipraga?= <alsi@bang-olufsen.dk>, 
	Florian Fainelli <f.fainelli@gmail.com>, Vladimir Oltean <olteanv@gmail.com>, 
	"David S. Miller" <davem@davemloft.net>, Eric Dumazet <edumazet@google.com>, 
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>, netdev@vger.kernel.org, 
	linux-kernel@vger.kernel.org, devicetree@vger.kernel.org
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Hi Andrew,

Em dom., 10 de mar. de 2024 =C3=A0s 15:02, Andrew Lunn <andrew@lunn.ch> esc=
reveu:
>> On Sun, Mar 10, 2024 at 01:51:58AM -0300, Luiz Angelo Daros de Luca wrot=
e:
> > Each port can have up to 4 LEDs (3 for current rtl8365mb devices). The
> > LED reg property will indicate its LED group.
> > +                properties:
> > +                  reg:
> > +                    description:
> > +                      "reg indicates the LED group for this LED"
> > +                    enum: [0, 1, 2, 3]
>
> If this identifies the group, what identifies the actual LED? There
> are four of them. How do i say LEDs 0 and 1 are unused, 2 and 3 are
> wired to LEDs?

Do we need to mention a specific HW is not present? I guess we just
omit it, like the led@1 and led@2 in the example.

> It would be much more usual for reg to be the LED number for the
> port. And there then be a group property indicating what group the LED
> belongs to. However, i'm wondering, is group fixed? Do we actually
> need it in DT, or can there just be a table in the driver which maps
> port:led to group?

The LED groups are a fixed HW feature. The chip has dedicated pins for
each LED in each group. Those pins might have an alternative usage (as
an GPIO) but you cannot change a LED from a group to another in SW.
That's why I thought it was a thing to be described in the DT.

>          Andrew

Regards,

Luiz