activity-led usage

[Yegor Yefremov]

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 :-)

Regards,
Yegor