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Message-ID: <9398f15b-6c50-b7ef-1886-c3c78f075e72@redhat.com>
Date: Thu, 9 Mar 2023 10:32:12 +0100
From: Hans de Goede <hdegoede@...hat.com>
To: Linus Walleij <linus.walleij@...aro.org>,
Christian Marangi <ansuelsmth@...il.com>
Cc: Pavel Machek <pavel@....cz>, Lee Jones <lee@...nel.org>,
Rob Herring <robh+dt@...nel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
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>,
Heiner Kallweit <hkallweit1@...il.com>,
Russell King <linux@...linux.org.uk>,
Jonathan Corbet <corbet@....net>,
"Russell King (Oracle)" <rmk+kernel@...linux.org.uk>,
Jacek Anaszewski <jacek.anaszewski@...il.com>,
John Crispin <john@...ozen.org>, linux-leds@...r.kernel.org,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
netdev@...r.kernel.org, linux-doc@...r.kernel.org,
Tim Harvey <tharvey@...eworks.com>,
Alexander Stein <alexander.stein@...tq-group.com>,
Rasmus Villemoes <rasmus.villemoes@...vas.dk>,
Bagas Sanjaya <bagasdotme@...il.com>,
Arun.Ramadoss@...rochip.com
Subject: Re: [PATCH v8 00/13] Adds support for PHY LEDs with offload triggers
Hi,
On 3/9/23 10:09, Linus Walleij wrote:
> Hi Christian,
>
> thanks for your patch!
>
> On Thu, Feb 16, 2023 at 2:36 AM Christian Marangi <ansuelsmth@...il.com> wrote:
>
>> The current idea is:
>> - LED driver implement 3 API (hw_control_status/start/stop).
>> They are used to put the LED in hardware mode and to configure the
>> various trigger.
>> - We have hardware triggers that are used to expose to userspace the
>> supported hardware mode and set the hardware mode on trigger
>> activation.
>> - We can also have triggers that both support hardware and software mode.
>> - The LED driver will declare each supported hardware blink mode and
>> communicate with the trigger all the supported blink modes that will
>> be available by sysfs.
>> - A trigger will use blink_set to configure the blink mode to active
>> in hardware mode.
>> - On hardware trigger activation, only the hardware mode is enabled but
>> the blink modes are not configured. The LED driver should reset any
>> link mode active by default.
>
> The series looks good as a start.
> There are some drivers and HW definitions etc for switch-controlled
> LEDs, which is great.
>
> I am a bit reluctant on the ambition to rely on configuration from sysfs
> for the triggers, and I am also puzzled to how a certain trigger on a
> certain LED is going to associate itself with, say, a certain port.
>
> I want to draw your attention to this recently merged patch series
> from Hans de Goede:
> https://lore.kernel.org/linux-leds/20230120114524.408368-1-hdegoede@redhat.com/
>
> This adds the devm_led_get() API which works similar to getting
> regulators, clocks, GPIOs or any other resources.
>
> It is not yet (I think) hooked into the device tree framework, but it
> supports software nodes so adding DT handling should be sort of
> trivial.
That series contains this (unmerged) patch to hookup DT handling:
https://lore.kernel.org/linux-leds/20230120114524.408368-6-hdegoede@redhat.com/
this was not merged because there are no current users, but adding
support is as easy as picking up that patch :)
Note there also already is a devicetree *only*:
struct led_classdev *of_led_get(struct device_node *np, int index);
Since I was working on a x86/ACPI platform I needed something more
generic though and ideally new code would use the generic approach.
Regards,
Hans
>
> I think the ambition should be something like this (conjured example)
> for a DSA switch:
>
> platform {
> switch {
> compatible = "foo";
>
> leds {
> #address-cells = <1>;
> #size-cells = <0>;
> led0: led@0 {
> reg = <0>;
> color =...
> function = ...
> function-enumerator = ...
> default-state = ...
> };
> led1: led@1 {
> reg = <1>;
> color =...
> function = ...
> function-enumerator = ...
> default-state = ...
> };
> };
>
> ports {
> #address-cells = <1>;
> #size-cells = <0>;
> port@0 {
> reg = <0>;
> label = "lan0";
> phy-handle = <&phy0>;
> leds = <&led0>;
> };
> port@1 {
> reg = <1>;
> label = "lan1";
> phy-handle = <&phy1>;
> leds = <&led0>;
> };
> };
>
> mdio {
> compatible = "foo-mdio";
> #address-cells = <1>;
> #size-cells = <0>;
>
> phy0: ethernet-phy@0 {
> reg = <0>;
> };
> phy1: ethernet-phy@1 {
> reg = <1>;
> };
> };
> };
> };
>
> I am not the man to tell whether the leds = <&led0>; phandle should be on
> the port or actually on the phy, it may even vary. You guys know the answer
> to this.
>
> But certainly something like this resource phandle will be necessary to
> assign the right LED to the right port or phy, I hope you were not going
> to rely on strings and naming conventions?
>
> Yours,
> Linus Walleij
>
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