activity-led usage

[Heiko Schocher]

Hello Yegor,

On 02.10.25 13:28, Yegor Yefremov wrote:
> Hi Heiko,
> 
> On Thu, Oct 2, 2025 at 10:26 AM Heiko Schocher <hs at nabladev.com> wrote:
>>
>> Hello Yegor,
>>
>> On 02.10.25 10:22, Yegor Yefremov wrote:
>>> Hi Simon and Marek,
>>>
>>> On Wed, Oct 1, 2025 at 1:09 AM Simon Glass <sjg at chromium.org> wrote:
>>>>
>>>> Hi Yegor,
>>>>
>>>> On Tue, 30 Sept 2025 at 08:48, Yegor Yefremov
>>>> <yegorslists at googlemail.com> wrote:
>>>>>
>>>>> Hi Simon,
>>>>>
>>>>> On Tue, Sep 30, 2025 at 4:13 PM Simon Glass <sjg at chromium.org> wrote:
>>>>>>
>>>>>> Hi Yegor,
>>>>>>
>>>>>> On Tue, 30 Sept 2025 at 06:35, Yegor Yefremov
>>>>>> <yegorslists at googlemail.com> wrote:
>>>>>>>
>>>>>>> On Tue, Sep 30, 2025 at 12:29 PM Yegor Yefremov
>>>>>>> <yegorslists at googlemail.com> wrote:
>>>>>>>>
>>>>>>>> Hi all,
>>>>>>>>
>>>>>>>> I added the following LED definition to the am335x-baltos.dts:
>>>>>>>>
>>>>>>>>           leds {
>>>>>>>>                   pinctrl-names = "default";
>>>>>>>>                   pinctrl-0 = <&user_leds>;
>>>>>>>>
>>>>>>>>                   compatible = "gpio-leds";
>>>>>>>>
>>>>>>>>                   led-power {
>>>>>>>>                           label = "led-red";
>>>>>>>>                           gpios = <&gpio3 0 GPIO_ACTIVE_LOW>;
>>>>>>>>                           default-state = "on";
>>>>>>>>                   };
>>>>>>>>           };
>>>>>>>>           user_leds: user-leds-pins {
>>>>>>>>                   pinctrl-single,pins = <
>>>>>>>>                           AM33XX_PADCONF(AM335X_PIN_MII1_COL,
>>>>>>>> PIN_OUTPUT_PULLDOWN, MUX_MODE7)     /* mii1_col.gpio3_0 PWR LED */
>>>>>>>>                   >;
>>>>>>>>           };
>>>>>>>>
>>>>>>>> The gpio-leds driver is working and I can toggle the led-red via the
>>>>>>>> led command.
>>>>>>>>
>>>>>>>> Then, I created an am335x-baltos-u-boot.dtsi file with the following content:
>>>>>>>>
>>>>>>>> / {
>>>>>>>>       config {
>>>>>>>>           u-boot,activity-led = "led-red";
>>>>>>>>       };
>>>>>>>> };
>>>>>>>>
>>>>>>>> I have also tried "led-power" instead of "led-red".
>>>>>>>>
>>>>>>>> In my final DTS files I have the following nodes:
>>>>>>>>
>>>>>>>>           leds {
>>>>>>>>                   pinctrl-names = "default";
>>>>>>>>                   pinctrl-0 = <0x56>;
>>>>>>>>                   compatible = "gpio-leds";
>>>>>>>>
>>>>>>>>                   led-power {
>>>>>>>>                           label = "led-red";
>>>>>>>>                           gpios = <0x57 0x00 0x01>;
>>>>>>>>                           default-state = "on";
>>>>>>>>                   };
>>>>>>>>           };
>>>>>>>>
>>>>>>>>           config {
>>>>>>>>                   u-boot,activity-led = "led-red";
>>>>>>>>           };
>>>>>>>>
>>>>>>>> U-Boot cannot find the activity-led node.
>>>>>>>> ofnode_options_get_by_phandle("activity-led", &led_node); returns -22,
>>>>>>>> because ofnode_path("/options/u-boot") fails.
>>>>>>>>
>>>>>>>> When driver debug is enabled, I also see the following messages:
>>>>>>>>
>>>>>>>> bind node config
>>>>>>>> Device 'config' has no compatible string
>>>>>>>>
>>>>>>>> My am335x-baltos-u-boot.dtsi code is similar to what I could find in
>>>>>>>> arch/arm/dts for the boot-led usage.
>>>>>>>>
>>>>>>>> Where should I debug further?
>>>>>>
>>>>>> It is a bit confusing as there is still 'legacy' LED stuff in the
>>>>>> tree. For your problem I would suggest checking that the LED device is
>>>>>> configured correctly.
>>>>>>
>>>>>> For sandbox in test.dts you can see:
>>>>>>
>>>>>>       options {
>>>>>>           u-boot {
>>>>>>               compatible = "u-boot,config";
>>>>>>               boot-led = <&sandbox_led_green>;
>>>>>>               activity-led = <&sandbox_led_red>;
>>>>>> ...
>>>>>>           };
>>>>>>       };
>>>>>>
>>>>>> Check that led_init() is being called in the LED uclass.
>>>>>
>>>>> It is working now using your suggestion. Thanks.
>>>>>
>>>>>>>
>>>>>>> Should activity-led be also mentioned in doc/device-tree-bindings/config.txt?
>>>>>>
>>>>>> We should be using /options/u-boot for this[1]
>>>>>
>>>>> This means, everything that can be found via the following command
>>>>> won't work and should be removed?
>>>>>
>>>>> grep -r --include='*.dts[i]' boot-led arch/arm/dts
>>>>
>>>> Yes. I did a series to remove the legacy LED stuff last year but it
>>>> wasn't applied because people wanted me to do more, probably what you
>>>> are looking at doing now :-)
>>>
>>> This would be great if this patch series could be merged. Marek has a
>>> board (arch/arm/dts/stm32mp157a-dhcor-avenger96-u-boot.dtsi) that can
>>> be reworked too.
>>>
>>> AFAIK, led_activity_blink() is used very seldom. For example, in
>>> cmd/ubi.c it is only used for writing [1]. mmc is omitted completely.
>>> Is this intentional or is this functionality just missing?
>>>
>>> [1] https://github.com/u-boot/u-boot/blob/master/cmd/ubi.c#L494
>>
>> The commit which introduced this says:
>> """
>> commit 990f726ce797c040adda6d1e1bc6a21bd2b28657
>> Author: Christian Marangi <ansuelsmth at gmail.com>
>> Date:   Tue Oct 1 14:24:41 2024 +0200
>>
>>       ubi: implement support for LED activity
>>
>>       Implement support for LED activity. If the feature is enabled,
>>       make the defined ACTIVITY LED to signal ubi write operation.
>>
>>       Signed-off-by: Christian Marangi <ansuelsmth at gmail.com>
>>       Reviewed-by: Simon Glass <sjg at chromium.org>
>> """
>>
>> So, at that time it was intentional ... yes ... but I ask me, why
>> we do not use this LED also on read operations...
> 
> So, in other words, patches are welcome :-)

 From my side: Full Ack.

May we should ask "Christian Marangi <ansuelsmth at gmail.com>"
if there are some special reasons for only adding it to the write
command.

Thanks!

bye,
Heiko
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