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Message-ID: <CAL_JsqLOvCJ_aHk4jSp64u1LbGyoeTjY_vRgVkvvVNCOp=3NmA@mail.gmail.com>
Date: Wed, 21 Dec 2022 09:29:15 -0600
From: Rob Herring <robh@...nel.org>
To: Christian Marangi <ansuelsmth@...il.com>,
Jacek Anaszewski <jacek.anaszewski@...il.com>
Cc: Andrew Lunn <andrew@...n.ch>,
Florian Fainelli <f.fainelli@...il.com>,
Vladimir Oltean <olteanv@...il.com>,
"David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
Jonathan Corbet <corbet@....net>, Pavel Machek <pavel@....cz>,
"Russell King (Oracle)" <rmk+kernel@...linux.org.uk>,
John Crispin <john@...ozen.org>, netdev@...r.kernel.org,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-doc@...r.kernel.org, linux-leds@...r.kernel.org,
Tim Harvey <tharvey@...eworks.com>,
Alexander Stein <alexander.stein@...tq-group.com>,
Rasmus Villemoes <rasmus.villemoes@...vas.dk>
Subject: Re: [PATCH v7 11/11] dt-bindings: net: dsa: qca8k: add LEDs
definition example
On Wed, Dec 21, 2022 at 6:55 AM Christian Marangi <ansuelsmth@...il.com> wrote:
>
> On Wed, Dec 21, 2022 at 02:41:50AM +0100, Andrew Lunn wrote:
> > > > > + };
> > > > > +
> > > > > + led@1 {
> > > > > + reg = <1>;
> > > > > + color = <LED_COLOR_ID_AMBER>;
> > > > > + function = LED_FUNCTION_LAN;
> > > > > + function-enumerator = <1>;
> > > >
> > > > Typo? These are supposed to be unique. Can't you use 'reg' in your case?
> > >
> > > reg in this context is the address of the PHY on the MDIO bus. This is
> > > an Ethernet switch, so has many PHYs, each with its own address.
> >
> > Actually, i'm wrong about that. reg in this context is the LED number
> > of the PHY. Typically there are 2 or 3 LEDs per PHY.
> >
> > There is no reason the properties need to be unique. Often the LEDs
> > have 8 or 16 functions, identical for each LED, but with different
> > reset defaults so they show different things.
> >
>
> Are we taking about reg or function-enumerator?
>
> For reg it's really specific to the driver... My idea was that since a
> single phy can have multiple leds attached, reg will represent the led
> number.
>
> This is an example of the dt implemented on a real device.
>
> mdio {
> #address-cells = <1>;
> #size-cells = <0>;
>
> phy_port1: phy@0 {
> reg = <0>;
>
> leds {
> #address-cells = <1>;
> #size-cells = <0>;
>
> lan1_led@0 {
> reg = <0>;
> color = <LED_COLOR_ID_WHITE>;
> function = LED_FUNCTION_LAN;
> function-enumerator = <1>;
> linux,default-trigger = "netdev";
> };
>
> lan1_led@1 {
> reg = <1>;
> color = <LED_COLOR_ID_AMBER>;
> function = LED_FUNCTION_LAN;
> function-enumerator = <1>;
> linux,default-trigger = "netdev";
> };
> };
> };
>
> phy_port2: phy@1 {
> reg = <1>;
>
> leds {
> #address-cells = <1>;
> #size-cells = <0>;
>
>
> lan2_led@0 {
> reg = <0>;
> color = <LED_COLOR_ID_WHITE>;
> function = LED_FUNCTION_LAN;
> function-enumerator = <2>;
> linux,default-trigger = "netdev";
> };
>
> lan2_led@1 {
> reg = <1>;
> color = <LED_COLOR_ID_AMBER>;
> function = LED_FUNCTION_LAN;
> function-enumerator = <2>;
> linux,default-trigger = "netdev";
> };
> };
> };
>
> phy_port3: phy@2 {
> reg = <2>;
>
> leds {
> #address-cells = <1>;
> #size-cells = <0>;
>
> lan3_led@0 {
> reg = <0>;
> color = <LED_COLOR_ID_WHITE>;
> function = LED_FUNCTION_LAN;
> function-enumerator = <3>;
> linux,default-trigger = "netdev";
> };
>
> lan3_led@1 {
> reg = <1>;
> color = <LED_COLOR_ID_AMBER>;
> function = LED_FUNCTION_LAN;
> function-enumerator = <3>;
> linux,default-trigger = "netdev";
> };
> };
> };
>
> In the following implementation. Each port have 2 leds attached (out of
> 3) one white and one amber. The driver parse the reg and calculate the
> offset to set the correct option with the regs by also checking the phy
> number.
Okay, the full example makes more sense. But I still thought
'function-enumerator' values should be globally unique within a value
of 'function'. Maybe Jacek has an opinion on this?
You are using it to distinguish phys/ports, but there's already enough
information in the DT to do that. You have the parent nodes and I
assume you have port numbers under 'ethernet-ports'. For each port,
get the phy node and then get the LEDs.
> An alternative way would be set the reg to be the global led number in
> the switch and deatch the phy from the calculation.
>
> Something like
> port 0 led 0 = reg 0
> port 0 led 1 = reg 1
> port 1 led 0 = reg 2
> port 1 led 1 = reg 3
> ...
No.
Rob
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